The Pennsylvania State University
The Graduate School
Department of Mechanical and Nuclear Engineering
CHARACTERIZATION OF ITALIAN TILE SAMPLES USING COMPARATIVE
NEUTRON ACTIVATION ANALYSIS IN THE PENN STATE BREAZEALE NUCLEAR
REACTOR
A Thesis in
Nuclear Engineering
by
Chad B. Durrant
 2014 Chad B. Durrant
Submitted in Partial Fulfillment
of the Requirements
for the Degree of
Master of Science
May 2014
ii
The thesis of Chad B. Durrant was reviewed and approved* by the following:
Kenan Ünlü
Professor of Nuclear Engineering
Director of Radiation Science and Engineering Center
Thesis Advisor
Amanda M. Johnsen
Research Associate, Radiation Science and Engineering Center
Special Signatory
Karen A. Thole
Professor of Mechanical Engineering
Department Head of Mechanical and Nuclear Engineering
*Signatures are on file in the Graduate School
iii
ABSTRACT
Comparative neutron activation analysis (CNAA) is a powerful method that is used to
determine trace element compositions of unknown samples by comparing them with known
samples. This is accomplished by the activation of the samples with thermal neutrons and then
subsequently measuring the corresponding delayed gamma rays. There are three principal goals
achieved from this research: developing an irradiation fixture with suitable neutron fluences and
large sample number capacity, characterizing the thermal neutron flux of the irradiation fixture,
and determining the trace element composition of 15 Italian tiles. The Italian tiles come from two
archeological sites, Tarquinia and Veii in Italy. By determining the trace element composition of
the samples, the tiles can be separated into groups based on their composition. Archeologists
then use the composition data to determine where material used to make these tiles and other
similar artefacts originated from. Once the origins of these samples are determined other
conclusions such as trade and technology transfer in the region can be drawn. In order to use
CNAA at the Radiation Science and Engineering Center to determine the trace element
composition of 15 Italian tile samples, an irradiation fixture and sample holder were designed and
built for the Penn State Breazeale Reactor (PSBR). This sample holder allows up to 28 samples
to be irradiated simultaneously at relatively similar thermal neutron fluences. A short irradiation
with a total neutron fluence of ~ 6.1 x 1014 neutrons/cm2 and a long irradiation with total neutron
fluence of ~ 5.8 x 1017 neutrons/cm2 were performed. The irradiation fixture is also durable and
made mostly with high purity aluminum, thereby minimizing the impurities that can increase the
activity of the sample holder across multiple irradiations. An encapsulation method for the
samples was developed using high purity quartz ampoules to minimize the interferences in the
gamma spectra as well as minimize the activity produced. The thermal and epithermal neutron
flux profile of the sample holder was characterized using bare gold-aluminum wires and cadmium
iv
covered gold-aluminum wires. The total variation from highest to lowest thermal neutron flux
was ~30%. Lastly, the trace element compositions of the 15 Italian tile samples were determined
by CNAA. Between 13 and 16 trace elements were determined for each sample including:
sodium, potassium, manganese, strontium, europium, scandium, titanium, chromium, iron, zinc,
rubidium, antimony, barium, hafnium, calcium, and zirconium. The concentrations of the trace
elements determined ranged from hundreds of part per billion (ppb) for antimony to tens of
milligrams per gram for potassium, titanium, and iron. All other trace elements had
concentrations within that range. After the trace element compositions for each sample were
determined, the samples were analyzed and clustered into two groups of similar composition.
Group 1 is composed of samples 139B-148B and Group 2 is composed of samples 149B-153B.
Based upon comparisons with previous work Group 1 samples likely originate from Tarquinia
and Group 2 samples likely originate from Veii. The elements primarily responsible for these
groupings are europium, chromium, hafnium, scandium, rubidium and zirconium. Scatter plots
with europium and chromium as one of the trace elements concentrations give the most distinct
separation between the groupings. One exception is the zirconium plot of sample 145B, which
appears to suggest that sample 145B is part of neither group. This research also corroborates the
findings of previous studies and demonstrates the efficacy of CNAA as an analytical technique
for determining the trace element composition of Italian tile samples.
v
TABLE OF CONTENTS
List of Figures ......................................................................................................................... vi
List of Tables ........................................................................................................................... viii
Acknowledgements .................................................................................................................. x
Chapter 1 Introduction and Objectives .................................................................................... 1
Chapter 2 Neutron Activation Analysis Methods .................................................................... 4
2.1 Neutron Interactions ................................................................................................... 4
2.2 NAA Methods ............................................................................................................ 7
2.2.1 Instrumental NAA ................................................................................................... 7
2.2.2 Comparative NAA .................................................................................................. 8
2.2.3 Single Comparator NAA ......................................................................................... 9
Chapter 3 Application of NAA to Provenance Studies............................................................ 12
Chapter 4 Radiation Science and Engineering Center NAA Facility ...................................... 15
4.1 The Penn State Breazeale Nuclear Reactor (PSBR) .................................................. 15
4.2 RSEC Radionuclear Applications Laboratory ........................................................... 17
4.3 The PSBR 2” x 6” Irradiation Fixture ........................................................................ 20
4.4 The Sample Holder for the 2” x 6” Irradiation Fixture .............................................. 22
4.5 Neutron Flux Characterization of the 2” x 6” Irradiation Fixture .............................. 25
4.6 Irradiation Preparation and Procedures ...................................................................... 30
4.7 Error Propagation ....................................................................................................... 39
Chapter 5 Experimental Results............................................................................................... 40
5.1 Italian Tiles Data Summary ....................................................................................... 40
5.2 Quality Control Data .................................................................................................. 45
Chapter 6 Analysis of CNAA Results...................................................................................... 47
Chapter 7 Conclusions and Future Work ................................................................................. 53
References ................................................................................................................................ 57
Appendix A
Appendix B
Appendix C
Appendix D
Physical Specifications ............................................................................... 63
NIST Certificates ........................................................................................ 65
Procedures .................................................................................................. 69
Comprehensive Sample Data...................................................................... 93
vi
LIST OF FIGURES
Figure 4.1. A map of the PSBR core loading number 54. ....................................................... 16
Figure 4.2. A map of the PSBR core loading number 55. ....................................................... 16
Figure 4.3. The Automatic Sample Handling System (ASHS) used for counting samples. .... 18
Figure 4.4. The rotating sample holder, which can hold up to 90 samples at a time. .............. 18
Figure 4.5. On the left is the HPGe detector, lead shielding, and pneumatic arm (red) that
receives the sample from the ASHS arm and lowers the samples into the shielding.
On the right is the computer and DSA 2000 used to collect and analyze the data. .......... 19
Figure 4.6. A schematic diagram of the 2 x 6 tube and the accompanying shield plug [17]. .. 21
Figure 4.7. The sample holder with the hinges opened. .......................................................... 23
Figure 4.8. The sample holder with the hinges closed. The first number represents the
position number (1-28) in the sample holder. The second number is the sample
(139B-153B), the plastic clay standard (S1-S5) or brick clay quality control (B1B5). The sample holder faces the reactor core from this position................................... 24
Figure 4.9. The normalized thermal neutron flux in the sample holder. .................................. 28
Figure 4.10. The certified elements and concentrations of the plastic clay SRM 98b. ............ 31
Figure 4.11. Uncertified elements and concentrations in the plastic clay SRM 679. .............. 31
Figure 4.12. A picture of the 15 Italian tile samples after being sealed in quartz ampoules. .. 35
Figure 5.1. An example gamma spectra that was obtained from counting sample 147B. ....... 44
Figure 6.1. A scatter plot that shows the sodium and potassium trace element
compositions of the tile samples. No distinct groups are found...................................... 49
Figure 6.2. A scatter plot of the europium and chromium trace element compositions for
the tile samples. Two distinct groups appear. ................................................................. 50
Figure 6.3. A scatter plot of the rubidium and zirconium trace element compositions for
the tile samples. The outlier is from sample 145B. ......................................................... 50
Figure A.1. HPGe detector dimensions provided by the manufacturer. .................................. 63
Figure A.2. A diagram of the PSBR core and 2 x 6 tube fixture coupling to the core [17]. .... 64
Figure D.1. A scatter plot of europium and rubidium trace element concentrations in the
Italian tiles. ....................................................................................................................... 106
vii
Figure D.2. A scatter plot of europium and scandium trace element concentrations in the
Italian tiles. ....................................................................................................................... 106
Figure D.3. A scatter plot of europium and hafnium trace element concentrations in the
Italian tiles. ....................................................................................................................... 107
Figure D.4. A scatter plot of europium and zirconium trace element concentrations in the
Italian tiles. ....................................................................................................................... 107
Figure D.5. A scatter plot of hafnium and chromium trace element concentrations in the
Italian tiles. ....................................................................................................................... 108
Figure D.6. A scatter plot of hafnium and rubidium trace element concentrations in the
Italian tiles. ....................................................................................................................... 108
Figure D.7. A scatter plot of hafnium and scandium trace element concentrations in the
Italian tiles. ....................................................................................................................... 109
Figure D.8. A scatter plot of hafnium and zirconium trace element concentrations in the
Italian tiles. ....................................................................................................................... 109
Figure D.9. A scatter plot of chromium and scandium trace element concentrations in the
Italian tiles. ....................................................................................................................... 110
Figure D.10. A scatter plot of chromium and rubidium trace element concentrations in the
Italian tiles. ....................................................................................................................... 110
Figure D.11. A scatter plot of chromium and zirconium trace element concentrations in
the Italian tiles. ................................................................................................................. 111
Figure D.12. A scatter plot of scandium and rubidium trace element concentrations in the
Italian tiles. ....................................................................................................................... 111
Figure D.13. A scatter plot of scandium and zirconium trace element concentrations in
the Italian tiles. ................................................................................................................. 112
viii
LIST OF TABLES
Table 4.1. Analysis Sequence Steps. ....................................................................................... 19
Table 4.2. The Thermal Neutron Flux Profile of the Sample Holder at the Core Face. .......... 27
Table 4.3. Heraeus Suprasil 310 Quartz Manufacturer Reported Impurities [26]. .................. 33
Table 5.1. Sample 147B Trace Element Composition. ............................................................ 41
Table 5.2. Trace Element Concentrations. ............................................................................... 43
Table 5.3. A Summary of Quality Control Sample #4............................................................. 46
Table 6.1. MCD Grouping Data for the Pottery Samples. ....................................................... 48
Table 6.2. SMED Group Variance Data for the Pottery Samples. ........................................... 51
Table 6.3. Group 1 Statistics. ................................................................................................... 52
Table 6.4. Group 2 Statistics. ................................................................................................... 52
Table D.1. Experimentally determined composition of Sample 139B using the plastic
clay comparator standard. ................................................................................................ 93
Table D.2. Experimentally determined composition of Sample 140B using the plastic
clay comparator standard. ................................................................................................ 93
Table D.3. Experimentally determined composition of Sample 141B using the plastic
clay comparator standard. ................................................................................................ 94
Table D.4. Experimentally determined composition of Sample 142B using the plastic
clay comparator standard. ................................................................................................ 94
Table D.5. Experimentally determined composition of Sample 143B using the plastic
clay comparator standard. ................................................................................................ 94
Table D.6. Experimentally determined composition of Sample 144B using the plastic
clay comparator standard. ................................................................................................ 95
Table D.7. Experimentally determined composition of Sample 145B using the plastic
clay comparator standard. ................................................................................................ 95
Table D.8. Experimentally determined composition of Sample 146B using the plastic
clay comparator standard. ................................................................................................ 96
Table D.9. Experimentally determined composition of Sample 147B using the plastic
clay comparator standard. ................................................................................................ 96
ix
Table D.10. Experimentally determined composition of Sample 148B using the plastic
clay comparator standard. ................................................................................................ 97
Table D.11. Experimentally determined composition of Sample 149B using the plastic
clay comparator standard. ................................................................................................ 97
Table D.12. Experimentally determined composition of Sample 150B using the plastic
clay comparator standard. ................................................................................................ 97
Table D.13. Experimentally determined composition of Sample 151B using the plastic
clay comparator standard. ................................................................................................ 98
Table D.14. Experimentally determined composition of Sample 152B using the plastic
clay comparator standard. ................................................................................................ 98
Table D.15. Experimentally determined composition of Sample 153B using the plastic
clay comparator standard. ................................................................................................ 98
Table D.16. Experimentally determined composition of standard B1 using the plastic clay
comparator standard. ........................................................................................................ 99
Table D.17. Experimentally determined composition of standard B2 using the plastic clay
comparator standard. ........................................................................................................ 100
Table D.18. Experimentally determined composition of standard B3 using the plastic clay
comparator standard. ........................................................................................................ 101
Table D.19. Experimentally determined composition of standard B4 using the plastic clay
comparator standard. ........................................................................................................ 102
Table D.20. Experimentally determined composition of standard B5 using the plastic clay
comparator standard. ........................................................................................................ 103
Table D.21. Tabulated Mean Character Difference (MCD) Values for Italian Tile
Samples. ........................................................................................................................... 104
Table D.22. Tabulated Squared Mean Euclidian Distance (SMED) Values for the Italian
Tiles.................................................................................................................................. 105
x
ACKNOWLEDGEMENTS
I would like to thank my advisor Dr. Kenan Ünlü for his direction as I carried out my
research and for his assistance as I achieve my academic and professional goals. I would also like
to thank the staff of the Radiation Science and Engineering Center, especially Dr. Brenden
Heidrich and Thierry Daubenspeck for their ideas and insights in developing equipment apparatus
and Ron Aiken for machining and building said equipment and for allowing me to use his shop
for many hours while learning how to make quartz ampoules. Many thanks also to Dr. Amanda
Johnsen for her meticulous instruction in the laboratory and for the countless hours she spent
proofreading this manuscript. I would like to thank Eric Boeldt and Dave Bertocchi from
Environmental Health and Safety for their assistance in developing safe handling procedures and
releasing numerous samples to me. I would like to also thank my fellow graduate students Sarah
Bender, Kassia Kelley, and Dağistan Şahin for their help in gamma spectroscopy and many other
academic questions. Most importantly I would thank my family. My parents for support and
encouragement and especially my wife Sojin and daughter Eleanor for their love, patience, and
support while I spent many long days and weekends both in the laboratory and writing. Their
happy smiles made many long and difficult days manageable.
I would like to acknowledge my fellowship and source of funding as this research was
performed under the Nuclear Forensics Graduate Fellowship Program, which is sponsored by the
U.S. Department of Homeland Security, Domestic Nuclear Detection Office and the U.S.
Department of Defense, Defense Threat Reduction Agency. This material is based upon work
supported by the U.S. Department of Homeland Security under Grant Award Number, 2012-DN130-NF0001-02. The views and conclusions contained in this document are those of the author
and should not be interpreted as necessarily representing the official policies, either expressed or
implied, of the U.S. Department of Homeland Security.
1
Chapter 1
Introduction and Objectives
Archaeology is a multi-disciplinary approach to the study of the development of human
civilizations and societies. Artifacts from these ancient civilizations such as tools, pottery,
jewelry, etc. are studied by archaeologists using chemical, physical, biological, and many other
means in order to draw conclusions about how these societies operated and evolved. Among the
multitude of civilizations studied, ancient Rome is one the most common and fascinating due to
the complex and unique technological advancement of the society as a whole. One aspect of
ancient Rome that is of particular interest to archeologists is the study of technology transfer of
tile fabrication throughout Italy during the period from approximately 650 B.C. to 500 B.C.
Some of the questions that these archaeologists seek to answer include: if tile fabrication
technology originated in Rome or if it was obtained elsewhere, how or if that technology was
transferred throughout Italy, where were the tiles fabricated, and were there multiple fabrication
sites in use during this tile-making period [1, 2].
In order to answer the questions related to tile fabrication, archaeologists have analyzed
numerous tile samples from excavation sites and compared them to soil samples from cores
drilled at many of the same sites as well as some know clay deposits. Traditionally, the analysis
of these tiles used more rudimentary means such as a classification of types based upon the
iconography and style of the tiles. More recently technical methods such as petrography and
neutron activation analysis (NAA) have been applied to the analysis of these tiles. Petrography
takes thin slices of the tiles and uses transmitted light microscopy in order to specify
characteristics within the tile or clay sample including: the arrangement, size, shape, frequency
2
and composition of the sample components [1]. NAA is a non-destructive analysis technique that
gives detailed information about the chemical composition of the sample, including trace
elements. NAA is one of the focal points of this thesis and the methodology is discussed in depth
in Chapter 2. Other analysis methods of the soil samples also included size fractionation analysis
to determine size and percentage of particles that constitute a particular sample, allowing for the
classification of the samples as clays, silts, or sands, with clays having the smallest particle size
and sands having largest. Clay samples can be analyzed further by firing them in a kiln and
performing thermogravimetric analysis (TGA) and differential thermal analysis (DTA) with
results used to determine whether a clay was of sufficient quality to be used in the production of
tiles [1].
Thus far these methods have enabled archaeologists to conclude that a significant clay
source used in making many of the tiles within Rome and throughout Italy is located in Rome at a
site called the Velabrum. Three different tile compositions have been identified with two of them
being far more common than the third. Also, distinct patterns have arisen in the primary uses of
the different tile types largely due to the ability to identify the chemical fingerprint of both the
tiles and clay using NAA and supplemental information obtained through the other
characterization methods. In order to attain more conclusive results regarding the source(s) and
the transfer of tile-making technology many more samples will need to be analyzed [1, 2].
Using NAA to determine the trace element composition of these tile and clay samples is a
critical component in the evaluation of their provenance. The Penn State Breazeale Nuclear
Reactor (PSBR) is an excellent source for the thermal neutrons that are needed to perform INAA
on a set of 15 of these ancient Italian tile samples and thereby determine the trace element
composition of those samples. The PSBR also has extensive experience using INAA for
numerous dendrochronology experiments, as well as the necessary equipment including two dry
tubes in the reactor core that produce high thermal neutron fluxes. However, there are various
3
methods for INAA and the method used in this research necessitated the development of a new
irradiation fixture. There are specific advantages that can be gained from manufacturing a new
irradiation fixture and creating new procedures as opposed to using the existing dry tubes. These
advantages include being able to irradiate all of the samples together, having more uniform
irradiation conditions across all of the samples, and decreasing the error associated with
determining the trace element compositions of the tile samples.
There are three primary goals to accomplish from this research project. The first goal is to
develop an irradiation fixture for the PSBR that would achieve suitable neutron fluxes for use in
NAA analyses. The irradiation fixture should also be able incorporate a large number of samples
at one time in order minimize the number of irradiations and shorten the irradiation time required
in the PSBR. The second goal is to characterize the thermal neutron flux in the new irradiation
fixture. This will determine how long the samples must be irradiated and the variance of the
thermal neutron flux vertically and axially across the irradiation fixture. Lastly the trace element
composition of the 15 ancient Italian tiles will be determined, and a correlation analysis
performed to determine the provenance of the samples.
4
Chapter 2
Neutron Activation Analysis Methods
Neutron activation analysis (NAA) is a non-destructive analysis technique used to
determine the elemental composition of materials. NAA is especially useful in determining trace
elements whose concentration may be in the parts per million (ppm) or even the parts per billion
(ppb) range, or may otherwise be difficult to obtain via standard chemical methods. The
methodology behind NAA develops from the interactions of neutrons with the atoms present in a
given material. There are three different processes by which neutrons can interact with atoms:
elastic scattering, inelastic scattering, and neutron capture or absorption. The neutron capture
interaction is especially important for NAA. There are also a number of different methods in
which NAA is applied. The absolute method of NAA involves determining the absolute
composition of a material and requires the accurate knowledge of several parameters. The single
comparator method of NAA entails using knowledge about one specific element, oftentimes gold,
and how it compares to many other elements in order to ascertain elemental composition in an
unknown material. Finally there is the relative or comparative method of NAA. This method uses
a material that is well characterized and similar to the unknown material and uses comparison
techniques to establish the composition of the unknown material.
2.1 Neutron Interactions
Neutrons are produced in a reactor or an accelerator and interact with matter in a number
of ways. These neutrons have neither positive nor electrical charge and therefore interact directly
with nucleus of an atom. Elastic scattering is a process whereby a neutron collides with the
nucleus of an atom and transfers an amount of energy the nucleus. The neutron recoils in a
5
different direction and with a different speed and the nucleus also recoils with direction and
speed. Kinetic energy is conserved in elastic scattering collisions. While recoiling with a small
fraction of energy from the neutron, the intrinsic composition of the nucleus, or number or
protons and neutrons, remains unchanged. The notation commonly used to describe these
reactions is (n, n), showing that the neutron interacts with the nucleus without effecting a
fundamental change to the nucleus.
Inelastic scattering is similar to elastic scattering in that a neutron collides with a nucleus
and transfers some of its energy. However, this energy is absorbed by the nucleus and the kinetic
energy of this physical system is not conserved. The nucleus still retains the same number of
protons and neutrons, but some of the energy absorbed from the neutron collision is converted to
internal energy and the nucleus reaches an excited state. Eventually the nucleus will release this
extra energy in the form of gamma rays and return to its natural or ground state. Inelastic
scattering reactions are denoted by (n, n’), where the neutron enters the system with a specific
energy state, but leaves the system under different energy conditions.
There are also neutron capture, or neutron absorption, reactions. Sometimes when a
neutron collides with a nucleus, the nucleus can capture, or absorb, the neutron. The likelihood of
this event happening is described as the neutron capture cross-section. The capture cross-section
for a given nucleus is dependent on factors such as the size and stability of the nucleus, and the
energy of the incident neutron. As the capture cross-section increases, the probability that the
neutron will be absorbed increases. After absorbing the neutron, the nucleus attains a highly
energized transition state from which energy must be released. For this particular work, gamma
rays emitted from the excited nucleus are of particular importance and will be discussed further.
Other methods by which the nucleus can release energy are described in detail elsewhere [3].
Radiative capture reactions are designated as (n, γ) indicating that a neutron entered the system
and a gamma ray exited the system.
6
The process by which a nucleus, excited from absorption of a neutron, emits a gamma
ray(s) and returns to a stable energy state is called radioactive decay. The rate at which a nucleus
undergoes decay is known as the half-life, the time for which it takes half of all excited nuclei to
return to a stable energy state, and the equation used to quantify this process is shown in Equation
2.1:
⁄
2.1
Where λ is the decay constant for the nucleus. The decay constant for each excited nucleus, or
radionuclide, is unique to that specific radionuclide. Just as there is a unique decay constant for
each radionuclide, the energies of the gamma rays that are emitted are unique to that specific
radionuclide. When the nucleus absorbs a neutron, there is an almost instantaneous release of
some of the absorbed energy in the form of a prompt gamma ray. The immediacy of prompt
gamma rays makes them difficult to record and is frequently less useful in identifying or
quantifying a radionuclide. After the emission of the prompt gamma ray the nucleus will still
retain some of the energy absorbed from the incident neutron. This energy will be subsequently
released as a delayed gamma ray or a series of delayed gamma rays. These delayed gamma rays
are emitted anywhere from seconds later to days or even months later. Using a high purity
germanium (HPGe) detector, the energies of these delayed gamma rays can be recorded and
finely resolved in order to identify the individual radionuclide. In this way, NAA is effective
because it uses these delayed gamma ray signatures to identify the elements in a material,
including multiple isotopes of the same element [4, 5]
7
2.2 NAA Methods
Using neutron activation analysis to determine the composition of a material has inherent
advantages, including: the ability to identify multiple elements simultaneously, the ability to
measure concentrations in the ppm and ppb ranges, and NAA is a non-destructive technique.
NAA relies on the ability of neutrons to be absorbed by the material and then recording and
analyzing the characteristic delayed gamma rays emitted therefrom. There are several variations
of NAA and three of the most common will be briefly discussed. All of the NAA methods use
the induced activity of a neutron-irradiated sample to determine the composition of a material. In
general, the activity of a neutron-irradiated sample is determined as shown in Equation 2.2. The
measured activity is then correlated to the sample concentration.
2.2
Where A is the induced activity, σabs is the absorption cross section of the target isotope, ϕth is the
thermal neutron flux, N is the number of atoms of a specific isotope in the material, λ is the decay
constant of the daughter isotope, and t is the decay time. The thermal neutron flux is the number
of neutrons crossing a specified cross-sectional area and is discussed further in chapter 4.5.
2.2.1 Instrumental NAA
Instrumental neutron activation analysis (INAA) is also known as the absolute method
and is very sensitive to an accurate knowledge of a number of experimental parameters. INAA
gives the absolute concentration of an element or isotope in a material but there are also some
intrinsic limitations with this method. A very accurate knowledge of the thermal neutron flux
received by the material is necessary in order to determine how many atoms were activated.
Effects such as self-shielding within the materials must also be accounted for. Another limitation
8
arises from significant variation in the measured activity relative to small changes in the
efficiency of the HPGe detector used to measure the sample activity. The efficiency and
calibration of the detector is affected by slight variation in parameters such as sample size, sample
orientation, etc. When trying to analyze more than a few samples, maintaining the efficiency and
calibration of the detector as well as determining accurate neutron flux values for each sample
becomes important. This is much easier to accomplish when there are few samples that are very
uniform in size and the sample is composed of relatively few elements.
2.2.2 Comparative NAA
Comparative NAA (CNAA), also known as the relative method, is another approach to
determining the concentration of an element or isotope in a material. This relative method
compares an unknown sample with a known standard and uses a relationship between the activity
of the unknown sample and the activity and known composition of the standard to determine the
composition of the unknown sample. This method is useful for situations in which a suitable
standard can be found that has a similar geometry, background matrix, and trace element
composition as the unknown sample. By irradiating the standard and samples together, exact
knowledge of the neutron flux no longer becomes necessary, assuming the two materials are
exposed to the same relative neutron flux. Determining the composition of an unknown sample
with CNAA does not require accurate knowledge of the thermal neutron flux and efficiency and
calibration of the HPGe detector system as is required by INAA and thus trace element
composition is ascertained more simply with CNAA than INAA. The concentration of an
element in an unknown sample using CNAA is found by:
2.3
9
Where the subscript s refers to the standard used in the comparison, w is the concentration of the
target element (in either wt%, ppm, or ppb, as long as units are consistent), m is the mass of the
sample, A is the decay rate of the product nuclide in Becquerels (Bq), D is the decay correction
factor, C is the measurement counting factor, and ϕ is the relative flux correction based on the
position of the sample in the sample holder [6, 7].
While CNAA has many advantages, there are some general disadvantages as well. When
using the relative method of CNAA, comparing the sample with a standard that is similar in
shape, weight, composition, matrix, etc. is imperative. Thus, if a suitable standard is not available
the error when using this method will increase, possibly to an extent where CNAA is not an
appropriate approach. Also, using the relative method of CNAA increases the number of samples
that must be irradiated, thereby possibly increasing the number of irradiations that must be
performed, introducing the possibility of variations in the neutron flux over multiple irradiations.
The neutron flux profile itself can vary across the multiple samples within the same irradiation.
Another disadvantage is that quantitative analysis of unexpected elements present in the sample
cannot be performed because there is no standard with which to compare.
2.2.3 Single Comparator NAA
In some situations where a satisfactory standard is unavailable, prohibitively expensive,
or time-consuming to produce, the single comparator NAA method is alternative approach. The
single comparator NAA method makes a multi-element analysis similar to CNAA, while
irradiating and measuring only a single element, most commonly gold, as the standard. This
method was first evaluated by Girardi et al [8]. The single comparator method uses
experimentally-determined k factors, which are a comparison of the specific activities of the
10
comparator and the samples, to analyze the composition of the samples. Equations 2.4 and 2.5
show how these k factors are calculated [9].
2.4
with
2.5
where * represents properties of the single comparator or monitor,
Asp is the specific count rate
M is the atomic weight of the irradiated element,
Θ is the isotopic abundance of the target nuclide,
γ is the absolute abundance of the measured γ-ray,
ϵp is the full-energy peak efficiency of the detector for the measured γ-ray energy,
Φ is the conventional reactor neutron flux in neutron∙cm-2∙sec-1,
σ is the effective reactor neutron cross-section in barns,
S = 1-exp(-λtirr), is the activity saturation factor dependent on the decay constant
(λ), and the irradiation time, (tirr),
D = exp(-λtd), is the decay factor and td is the decay time period,
C = [1-exp(-λtm)]/ λtm, which is a measurement correction factor for decay during
the measurement time period tm,
Ap = is the measured average intensity of the full-energy peak (counts/sec),
w is the weight of the element in grams.
Usually the comparator is a small, thin foil or piece of wire that is placed directly beside
the sample ensuring that the flux ratio between the comparator and the sample is effectively unity.
11
This method initially necessitates the use of many standards in order to determine the k factors.
The concentrations of the sample are dependent on the experimentally determined k factors, and
thus the error present in the calculation of the elemental composition of the sample is directly
related to the accuracy of those k factors. The k0 method is a refinement of the single comparator
method is discussed in greater depth elsewhere [9-11].
The comparative method (CNAA) was chosen for this work for several reasons. First, it
was determined that suitable standards were available to use for comparison to the tile samples
and that using the standards would not increase the number of irradiations needed to complete the
analysis. The single comparator method or k0 method becomes significantly less accurate for
some of the trace elements that are analyzed, including europium, whereas assuming the trace
element concentrations of the standard were known accurately for those elements and should not
change dramatically. The CNAA also allowed for rather simple analysis by removing the
sensitivity of many of the measurement parameters that are present in INAA.
12
Chapter 3
Application of NAA to Provenance Studies
Determining the provenance of various pottery and tile sherds is one of the primary goals
for archaeological studies. Application of NAA techniques to these provenance studies began in
the late 1950s and, through a great deal of refinement, has become a mature process for
identifying the composition of the pottery, tile, and rock samples. A discussion of the
development and refinement of these NAA techniques is followed by a brief description of the
tile samples used in this project.
The use of neutron-induced radioactivity to make inferences regarding the chemical
composition of a material, thus proving the concept of NAA, began in the mid-1930s [27].
However, an established NAA technique that could accurately quantify trace element chemical
compositions was not developed until the late 1950s when Sayre and Dodson [28] and Emeleus
[29] first used the technique on pottery and coins, respectively. However, the germanium
detectors used at the time had poor energy resolution, thus very few elements could be
determined precisely, due to overlapping energy peaks [28-30]. From these initial studies 24Na,
42
K, 56Mn, and 46Sc were the primary isotopes found with certainty using absolute NAA.
Throughout the 1960s lithium drifted germanium detectors were developed, which significantly
improved their energy resolution, thereby greatly improving the capability of NAA to more
accurately quantify trace element concentrations of additional elements [31].
The improvement in detector energy resolution coincided with the development of the
comparative method of NAA and led to the seminal paper on pottery analysis using NAA by
Perlman and Asaro in 1969 [32]. Perlman and Asaro explained in rigorous detail the procedure
for making their comparator standard as well as their methods using multiple irradiations and
counting periods. This procedure became the foundation by which most NAA work is carried out
13
in laboratories throughout the world today. Their work also established the ability of NAA to
identify more than 30 different trace elements useful for archaeological provenance studies.
Among the trace constituents used to determine provenance, some of the most common elements
are barium, chromium, cesium, europium, hafnium, rubidium, scandium, strontium, thorium, and
uranium [33-37]. By the 1980s, NAA, particularly comparative NAA, was the method of choice
to determine trace element composition and provenance of archaeological samples. However,
duplicating the efforts of Perlman and Asaro to make a pottery standard was difficult and tedious
for other NAA labs; instead, various NIST standards were used as the well-characterized
comparator for NAA analyses.
The trace element compositions of various pottery samples are used to determine
provenance according the ‘provenance postulate’ elucidated by Weigand and colleagues in 1977
[31, 38]. The provenance postulate states that there exist sufficient differences in the chemical
makeup of raw materials that exceed allowable variation within a given source. Thus, the
variations in the trace element composition of samples within Group A and within Group B
should be less than the variation between the trace element compositions between Group A and
Group B. Analyzing the variability of the trace element composition of a single sample and
comparing that to the variability of similar trace element compositions of a grouping is crucial to
the ability to determine inclusion of the single sample in the group and thereby the provenance of
the sample. This led to the application of multivariate grouping techniques to the analysis of NAA
trace element composition data [39]. More recently, these grouping techniques have been refined
and more sophisticated techniques, such as cluster analysis methods that build upon the
fundamental theories of multivariate grouping, are used in order to analyze tens or hundreds of
samples at once [40-42].
While CNAA may be the standard for archaeological provenance studies, it is not
exclusive and more recently other methods have been examined and compared to the
14
effectiveness of CNAA. In 1995 a group from the Pacific Northwest Laboratory and the
University of Florida performed a comparison on the accuracy of the absolute, comparative, and
k0 standardization methods of NAA. Their findings concluded that the absolute method was only
as good as the nuclear data, which is difficult to obtain accurately for a large number of samples,
and the k0 standardization method had the most accurate results [43]. The k0 standardization
method also is capable of evaluating many samples in a single irradiation, however, CNAA
continues as the primary method of analysis for archaeological samples due likely to its
familiarity and ability to irradiate and evaluate numerous samples in parallel. More recently
studies have compared NAA results to those obtained from X-ray fluorescence analysis (XRF),
portable X-ray fluorescence analysis (pXRF), inductively coupled plasma optical emission
spectrometry (ICP-OES), and inductively coupled plasma mass spectrometry (ICP-MS). Each of
these methods produced initial results within ± 10 % of the NAA results, depending on the lab
and the technique used. ICP-MS generally compared favorably to NAA [36, 38] with most of the
ICP-MS results yielding slightly (a few percent) more accurate trace element composition results.
Even with promising initial results ICP-MS remains a secondary technique to NAA for most
provenance studies likely do to the familiarity and abundance of NAA laboratories as well as time
and labor intensive sample preparation that is needed in order to perform ICP-MS.
15
Chapter 4
Radiation Science and Engineering Center NAA Facility
The Radiation Science and Engineering Center (RSEC) houses the Penn State Breazeale
Nuclear Reactor (PSBR) which provides an excellent source of neutrons necessary for NAA. The
development and characterization of an additional irradiation fixture and apparatus, fuel
encapsulation procedures, and the selection of standard comparison materials is described in this
chapter. The RSEC also houses a Radionuclear Applications Laboratory that is essential for
NAA operations. The methods and procedures to use these facilities are discussed and this
chapter concludes with the sample preparation procedures.
4.1 The Penn State Breazeale Nuclear Reactor (PSBR)
The PSBR is the oldest continuously operating university research reactor in the United
States. While originally designed to use highly enriched material test reactor (MTR) plate type
fuel, the PSBR is now a TRIGA Mark III core that uses pin type fuel. The PSBR is power rated
for up to 1 MW at steady state operation and can be pulsed up to 2000 MW for approximately 10
milliseconds [12]. The reactor core is attached to a bridge that spans the open-water pool
containing 71,000 gallons of de-ionized water [13]. Moving the reactor bridge on rails also
allows the core to move to various locations throughout the pool, depending on the requirements
of a specific experiment or operation. The TRIGA fuel pins are made of a uranium zirconium
hydride matrix. The uranium content of the fuel pins is either 8.5 wt% or 12 wt% [14] and is
enriched in 235U to just under 20 %. The PSBR core loading, number 54, was used for
determining the flux profile and determining the initial trace element concentrations is shown in
16
Figure 4.1. The current PSBR core loading, number 55, was used for the quality control
irradiations and is shown in Figure 4.2
Figure 4.1. A map of the PSBR core loading number 54.
Figure 4.2. A map of the PSBR core loading number 55.
17
These maps of the PSBR core show the locations of the fuel rods, control rods, dry tubes,
and 2” x 6” irradiation fixture on the core face. In Figure 4.1 the dry tubes (E-4 and E-13), the
central thimble (H-9), and the 2 x 6 tube on the core face (B9-B11) are all positions where NAA
samples can be irradiated in the PSBR. The dry tubes are air filled positions that are similar in
size and shape to the fuel pins. The dry tubes are useful for many NAA applications and are
described further elsewhere [5, 15]. The irradiations carried out in this work used the 2 x 6
irradiation fixture, the physical features and characterization of which are discussed in section
4.3.
4.2 RSEC Radionuclear Applications Laboratory
The RSEC also houses a gamma ray counting laboratory essential for NAA
measurements, including several HPGe dectectors and Automatic Sample Handling Systems
(ASHS). After irradiation and before counting, each sample to be counted with a ASHS is placed
in a polyethylene vial and then into the rotating sample holder of the ASHS (Figures 4.3 and 4.4.
The ASHS can hold up to 90 samples and is used to transfer the samples one at time to the
detector for counting. The ability to count samples continuously increases the consistency of the
measurements and decreases the error in counting statistics by preventing extra periods of decay
time. The samples are counted with the following radiation detection and measurement
instrumentation: a Digital Spectrum Analyzer (DSA2000) and a CanberraTM model GC1518 High
Purity Germanium (HPGe) detector with a 76005L cryostat dewar. Manufacturer specifications
for the HPGe detector are included in Appendix A. The HPGe detector is enclosed with lead
shielding to eliminate most of the background radiation and a copper and tin liner inside the lead
to eliminate any X-rays resulting from gamma ray interactions with the lead shielding [16]. The
sample changer and detector equipment is shown in Figures 4.3-4.5.
18
Figure 4.3. The Automatic Sample Handling System (ASHS) used for counting samples.
Figure 4.4. The rotating sample holder, which can hold up to 90 samples at a time.
19
Figure 4.5. On the left is the HPGe detector, lead shielding, and pneumatic arm (red) that receives
the sample from the ASHS arm and lowers the samples into the shielding. On the right is the
computer and DSA 2000 used to collect and analyze the data.
Genie 2000 (v. 3.2) software (Canberra) is used to create an analysis sequence that is
used to process and analyze the spectrum obtained for each sample. The analysis sequence used
in this research is as follows:
Table 4.1. Analysis Sequence Steps.
Step 1: Peak Locate
Step 2: Peak Area
Step 3: Area Correction
Step 4: Efficiency Correction
Step 5: Nuclide Identification
Step 6: Parent Daughter Correction
Step 7: Detection Limits
Unidentified 2nd diff. (using a tolerance of 3.00 keV)
Sum/ Non-Linear LSQ Fit
Std. Bkg. Subtract (use current quartz background file)
Standard
NID w/ Interf. Corr. (with cascade correction)
PDC
Currie MDA
Step 1 identifies the tolerance used by algorithms for identifying peaks during the
program’s search of the gamma spectra. A tolerance of 3.00 keV means the algorithm will
20
identify peaks if they are within 3.00 keV of the value listed for that peak in the software peak
library. Step 2 is an algorithm that sums the area under the peak using a non-linear least squares
fit. Step 3 corrects the area under the identified peak by subtracting counts from a standard
background file. Step 4 is a preset algorithm that corrects for the efficiency of the detector. Step
5 identifies the nuclides using an algorithm that corrects for interferences from nearby peaks as
well as cascade peaks. Step 6 is a correction algorithm for a single iteration of a parent-daughter
decay chain. Finally, Step 7 calculates the radionuclide activities and gives minimum detectable
activity for other isotopes that may be present. After the spectrum has been processed a report
file detailing all of the analysis is created and saved as a Portable Document Format (PDF) file
and the edited spectrum file is saved under a new name so as to preserve the raw data file.
4.3 The PSBR 2” x 6” Irradiation Fixture
There are two important conditions that are considered for the irradiation of samples in
this project. The first condition is finding a position in the reactor that can maximize the thermal
neutron flux while minimizing the fast neutron flux seen by each of the samples, thereby
optimizing the (n,γ) thermal neutron activation reaction for a reasonable irradiation time of 10
hours or less. The second factor is finding a location in the reactor where a large number of
samples (>20) can be irradiated simultaneously without experiencing a significant flux gradient
across the samples.
There are a number of irradiation locations within the reactor core, including two dry
tubes and a wet central thimble, both of which have a 1” diameter. However, due to the
geometries of the dry tubes, central thimble, and quartz encapsulation of the samples, the number
of samples irradiated at one time would be limited to approximately five or six samples. This
would increase the number of irradiations and irradiation time in the reactor fourfold. The 2” x
21
6” irradiation fixture is an alternative location capable of irradiating many samples at a time. The
2 x 6 tube is 24’ 6” in vertical height with a 2” by 6” rectangular cross section. The tube attaches
to the PSBR core face, as shown in Figure 4.1, via extra placeholders in the bottom grid plate of
the reactor core. Diagrams of the fixture coupling to the reactor and the 2 x 6 tube with the lifting
cradle are included in Appendix A.
Figure 4.6. A schematic diagram of the 2 x 6 tube and the accompanying shield plug [17].
22
A schematic of the 2 x 6 tube is shown in Figure 4.6 The tube is made out of aluminum
and at 70.25” from the bottom, a 1.25” diagonal section is included. This diagonal section
decreases the radiation intensity exiting through the top of the tube during irradiation. A shield
plug, also seen in Figure 4.6, made of lead, cadmium, and borated polyethylene is put in place to
further attenuate most of the remaining radiation that escapes the tube during sample irradiation
[17]. The shield plug does not completely attenuate the beam of gamma rays, particularly around
the edges of the 2 x 6 tube. This necessitated a modification in the irradiation procedure to ensure
safety and will be discussed in section 4.6 along with the other irradiation procedures. In order to
make use of this irradiation position a new sample holder was designed and the neutron flux of
that position was characterized.
4.4 The Sample Holder for the 2” x 6” Irradiation Fixture
Now that an irradiation position was determined, a sample holder for that location was
constructed with the help of the PSBR machinist, Ron Eaken. When designing the sample holder
the following features were considered: the sample holder should be able to hold more than
twenty samples, the samples should be as close together vertically and horizontally as possible to
minimize the neutron flux variation between samples, the size of each individual sample position
was constricted by the size of the sample’s quartz encapsulation (0.6 mm outer diameter and
approximately 4.5 cm in length), and finally the samples should be relatively easy to extricate
after irradiation to minimize worker exposure.
The finished sample holder is shown in Figures 4.7 and 4.8. The outer frame of the
sample holder came from previous experiments conducted in the 2 x 6 tube and was constructed
using aluminum 1100 (high purity aluminum). Aluminum 6061 (less pure, but available in the
correct dimensions) was used for all of the modifications including the addition of individual
23
tubes, hinges, and welds. Aluminum activation products have the advantage of decaying rather
quickly, however, 24Na and many of the impurities do not, and this sample holder was irradiated
multiple times within several weeks. Thus the highest possible aluminum purity was used in order
keep the personnel dose as low as possible and prevent as much of the continued buildup of
radioactive products within the holder as possible.
Figure 4.7. The sample holder with the hinges opened.
24
Figure 4.8. The sample holder with the hinges closed. The first number represents the position
number (1-28) in the sample holder. The second number is the sample (139B-153B), the plastic
clay standard (S1-S5) or brick clay quality control (B1-B5). The sample holder faces the reactor
core from this position.
The sample holder has two rows of 14 tubes which can each hold one sample. Each row
is also built with a hinge (Figure 4.7), to facilitate extracting the samples efficiently and more
importantly to decrease the vertical distance between samples in the two rows, allowing for a
25
more consistent neutron fluence between the samples in each row. This holder also eliminated
flux variations perpendicular to the core face (see Figure 4.1), as all samples were the same
distance from the core face. A pin is inserted from the top of the holder to ensure that the hinges
stay locked in place during irradiations. The sample holder is approximately 160 g of Al 1100
and approximately 100 g of Al 6061. The total height of the sample holder is 19.9 cm with a
distance of 6.6 cm from the bottom of the top row of samples to the bottom of the lower row of
samples. The sample holder is 14.2 cm across with a width of 3.8 cm.
4.5 Neutron Flux Characterization of the 2” x 6” Irradiation Fixture
The neutron flux is composed of fast, epithermal, and thermal neutrons. These neutrons
are classified by their velocity and thermal neutrons are present on the order of several
magnitudes more than either fast or epithermal neutrons. The location of the 2 x 6 tube just off
the core face provides for additional thermalization of fast neutrons that travel through the water
between the core and the tube. Thermal neutrons also provide the vast majority of the neutron
activation reactions that produce the radioactive species to be measured post-irradiation. In order
to use CNAA, the neutron fluence experienced by the sample should be the same as that
experienced by the standard. Since the neutron fluence across the sample holder is similar, but
not exactly the same, a correction factor needs to be applied. In order to apply this correction
factor, the neutron flux profile across the sample holder was determined. The characterized flux
profile was then normalized so that it could be used to adjust element concentrations between
samples and their respective comparator standard that may have received a different neutron
fluence during irradiation. This comparison and adjustment is necessary because the
concentration of a certain radionuclide produced via neutron activation is dependent on the
fluence and therefore differences between the neutron fluence experienced by the sample and
26
comparator standard must be accounted for. The thermal neutron flux across the sample holder
was characterized using gold-aluminum wires that are 0.112% gold by weight. A total of 28
wires were used with one in each tube in the holder. In order to determine the thermal and
epithermal neutron flux and validate the assumption that the epithermal neutron flux is negligible,
half of the wires were covered with cadmium. The wires in the odd-numbered tubes were bare
and the wires in the even-numbered tubes (see Figure 4.8) were cadmium covered. The relative
neutron flux values were therefore determined in pairs; 14 pairs of bare and cadmium covered
wires were irradiated and then analyzed to determine the flux profile in the sample holder. The
epithermal flux is determined by Equation 4.1:
4.1
Where Ccd is net count rate of the cadmium covered wire, λ is the half-life of Au198, tw is the
decay time between the end of irradiation and the start of counting, N0 is the number of gold
atoms in the gold-aluminum wire, ϵ is the detector efficiency, γ is the gamma ray abundance
factor, I0 is the resonance integral of an ideal dilute detector, Gres is the epithermal self-shielding
factor, and ti is the irradiation time. The thermal flux is determined by Equation 4.2:
[
(
)] (
)
4.2
where Gth is the thermal self-shielding factor, Cb is the net count rate of the bare wire, g is the
Westcott factor which accounts for the departures from the ideal 1/v detector cross section in the
thermal energy range, σ0 is the absorption cross section of gold, and f1 is a function, equal to
27
0.468 in this case, describing the epithermal activation of a 1/v detector in a specified energy
range [18-21].
Absolute and normalized thermal neutron flux values are shown in Table 4.2 and a graph
of the normalized thermal neutron flux profile is shown in Figure 4.9.
Table 4.2. The Thermal Neutron Flux Profile of the Sample Holder at the Core Face.
Position
1-2
3-4
5-6
7-8
9-10
11-12
13-14
15-16
17-18
19-20
21-22
23-24
25-26
27-28
Absolute Thermal Flux Normalized Thermal Flux
2.16619E+13
2.11064E+13
2.11847E+13
2.15286E+13
2.08343E+13
2.19083E+13
2.30111E+13
1.81369E+13
1.51649E+13
1.61837E+13
1.72485E+13
1.69789E+13
1.73853E+13
1.84836E+13
0.94136765
0.917224047
0.920626676
0.935571605
0.905401008
0.952075707
1
0.788178008
0.659024565
0.703300293
0.74957116
0.737857027
0.755517241
0.803247901
Positions 1-14 in the sample holder are on the top row going from left to right and positions 15-28
are on the bottom row going from left to right. These positions are oriented such that when
looking at the sample holder in the 2 x 6 tube from the core face, position 1 is on the top right and
position 15 is on the bottom right.
28
Normalized Flux
Thermal Flux Profile of the Sample
Holder
1.2
1
0.8
0.6
Top Row
0.4
Bottow Row
0.2
0
0
5
10
15
Position in Sample Holder
Figure 4.9. The normalized thermal neutron flux in the sample holder.
When using gold as a monitor to determine the neutron flux, gamma ray emissions from 198Au
produced in the 197Au(n,γ)198Au neutron capture reaction are counted and analyzed. However the
capture cross-section of the product isotope, 198Au(n,γ)199Au, is 25100 barns compared to 98.7
barns for the 197Au capture cross-section. Therefore the rate at which 198Au is transmuted to 199Au
should be investigated and the consequent effect of the 198Au burnup on the specific count rate of
198
Au should be evaluated. Following irradiation, the number of atoms for a particular product, or
daughter, nuclide i is found by Equation 4.3,
(
)
4.3
where Ni-1 is the number of parent nuclide atoms, (i.e. 197Au atoms are the parent to 198Au atoms),
σth,i-1, is the thermal neutron capture cross-section of the parent nuclide, ϕth is the thermal neutron
29
flux, tirr is the irradiation time, λi is the decay constant. When the half-life of the daughter nuclide
is much greater than the irradiation time, Equation 4.3 can be approximated as noted in Equation
4.4,
(
)
4.4
Taking two successive reactions, such as the neutron capture reactions for 197Au and 198Au, and
using equation 4.4, an approximate burnup factor for gold is determined from Equation 4.5 [22],
[
]
4.5
The irradiation time of the gold wires was 20 minutes (1200 s) and the thermal neutron flux at
position 1-2 is 2.17 x 1013 neutrons/cm2-s. Using equations 4.4 and 4.5, the burnup factor for the
Au(n,γ)198Au neutron capture reaction is calculated as follows:
197
First the number of 198Au atoms produced are calculated,
(
)
Then the number of 199Au atom produced are calculated,
(
)
Once the total number of 198,199Au atoms produced are calculated the burnup factor is calculated,
30
[
]
As the burnup factor approaches 1 the burnup effect decreases to 0. A burnup factor of 0.9993 is
much less than the errors associated with the thermal neutron flux calculation which indicates that
the burnup of 198Au is insignificant and therefore does not affect the neutron flux analysis.
Considerable burnup factors can only be achieved at exceptionally high neutron fluxes and
irradiation times greater than several hundred hours [22].
4.6 Irradiation Preparation and Procedures
Prior to irradiation of the Italian tile samples, a number of preparation steps and
irradiation procedures were developed and carried out.
Standards
In order to use Comparative Neutron Activation Analysis (the relative method), a
satisfactory reference material must be chosen to compare with the unknown samples. Some of
the contributing factors considered when selecting the standard reference material include: the
presence of desired trace elements in the standard in sufficient concentrations, the certification of
those trace element concentrations by a suitable standardization laboratory, and the similarity of
the standard matrix (i.e. density, composition) to the unknown samples [23]. After searching the
National Institute of Standards and Technology (NIST) Standard Reference Material (SRM)
database, two standards similar in matrix and trace elements to the Italian pottery samples were
selected, brick clay (NIST SRM 679) and plastic clay (NIST SRM 98b). After further
comparison of the two SRMs and based upon the above criteria it was decided that more of the
31
desired trace elements were present in plastic clay and in concentrations more akin to the
expected concentrations of the unknown Italian tile samples, and would be used as the main
comparator standard, while the other would be used for quality control purposes. Below in
Figures 4.10 and 4.11 are tables showing the elements present in the plastic clay SRM and their
respective concentrations.
Figure 4.10. The certified elements and concentrations of the plastic clay SRM 98b.
Figure 4.11. Uncertified elements and concentrations in the plastic clay SRM 679.
32
The difference between certified and uncertified elements is the number of methods used to
determine the concentrations of each element. The certified elements were determined by at least
two different methods whereas the uncertified elements are only determined by one method. The
uncertified elements for plastic clay were determined by neutron activation analysis. Complete
copies of the NIST Certificates of Analysis for these standard reference materials are included in
Appendix B.
Sample Preparation and Encapsulation
Irradiations at the Penn State Breazeale Nuclear Reactor (PSBR) are typically performed
with doubly encapsulated samples for safety purposes. For small samples and brief irradiations,
polyethylene or other plastics are ideal encapsulation materials. However, irradiations lasting
longer than five Mega-Watt (MW) hours produce unacceptable melting and brittleness in plastic
materials that compromise the integrity of the encapsulation material, leading to potential
radioactive contamination and sample cross-contamination.
To ensure sample integrity and personnel safety during and after a long (> 5 hours), full
power (1 MW) irradiation of the Italian pottery samples, a more physically robust and radiation
resistant encapsulation material and method was pursued. In addition to radiation tolerance, any
material used to contain irradiation samples would need to undergo very low levels of neutron
activation, for two reasons: first, to keep personnel dose low during sample handling and second,
many of the Italian tile samples are powders, and therefore it is not reasonable to transfer them
from their irradiation encapsulation before gamma ray counting measurements, necessitating a
low-background containment material. Quartz encapsulation is frequently used for long-term
sample irradiation because it is physically robust and contains few neutron activation
interferences. Heraeus Suprasil 310, a very high purity quartz with impurity concentrations less
33
than 0.01 ppm (Table 4.3) and available in tube form, is an eminently suitable sample
encapsulation material.
Table 4.3. Heraeus Suprasil 310 Quartz Manufacturer Reported Impurities [26].
Impurities
Aluminum
Calcium
Chromium
Copper
Iron
Potassium
Lithium
Magnesium
Sodium
Titanium
Suprasil-family
ppm
≤ 0.010
≤ 0.015
≤ 0.001
≤ 0.003
≤ 0.005
≤ 0.010
≤ 0.001
≤ 0.005
≤ 0.010
≤ 0.005
The expected concentrations of the elements listed in Table 4.3 present in the tile samples are on
the order of 10 ppm or greater. The smallest ratio of an expected elemental concentration in a tile
sample to the corresponding elemental concentration in the Suprasil quartz is 104 or greater
(<0.01%), thus the contribution of the activity from an element in the irradiated quartz to the
overall activity from the same element in the irradiated tile sample is negligible. The quartz also
does not have any impurities that when activated would cause any interference when measuring
γ-rays emitted from other activated elements of interest in the sample. One disadvantage of using
quartz encapsulation for the Italian tile samples is that quartz is composed almost entirely SiO2,
and silicon is a major component of the tile samples. Thus accurate quantification of silicon in
the tile samples is not possible with this encapsulation method.
The quartz ampoules for sample containment were made by sealing one end of a piece of
Heraeus Suprasil 310 quartz tubing, inner diameter 4 mm and outer diameter 6 mm, using a
propane-oxygen torch. The tubing was scored an appropriate length from the sealed end (average
~45 mm) and broken off. The half-sealed ampoule was cleaned with ethanol, air dried overnight
34
and weighed the next day. The sample material, either an Italian tile sample or a standard, was
then placed into the ampoule. Then a Kimwipe wetted with ethanol was used to wipe the dust
residue inside of the ampoule to about 1 cm down from the top. Once the ampoule was loaded
with sample material and the dust residue removed, the open end was then sealed with the torch
(final average length ~43.5mm). The ampoule length was determined such that there would be
sufficient distance between the sample and the sealed end to prevent scorching of the sample.
The sealed ampoule was then washed with ethanol to remove any contamination on the ampoule,
particularly sodium residues, wrapped in aluminum foil also washed with ethanol (extra
encapsulation in case of breakage during irradiation), and labelled for identification.
Italian Tile Samples
A set of 15 tile samples from two archeological sites, Tarquinia and Veii, Italy, were
obtained from Dr. Albert Ammerman and Dr. Rebecca Ammerman at Colgate University. The
samples were labelled 139B through 153B for identification purposes and this labelling was
maintained throughout experimentation. Eleven of the samples (139B-149B) were from the site
at Tarquinia and the remaining four samples (150B-153B) were from the site at Veii. The weight
of each sample varied from 30 mg to a little over 100 mg. The samples varied greatly in color,
shape, and form. Some were fine and powdered while others were hard, brittle, and rock-like.
Some samples were gray or ashen colored, some were brick red and some were much darker and
similar in color to igneous rock (Figure 4.12). The objective specified by the Colgate University
collaborators was to identify the trace element composition of each of the samples, especially
noting the concentrations of seven target trace elements previously identified in other similar
samples by two other research labs: europium, thorium, chromium, hafnium, cesium, scandium,
and rubidium.
35
Figure 4.12. A picture of the 15 Italian tile samples after being sealed in quartz ampoules.
Activity Prediction Program
Before any irradiations were performed, an activity prediction program developed by
RSEC graduate student Dagistan Sahin [24] was used to determine the approximate required total
neutron fluence, the post-irradiation activities of individual radioisotopes, exposure rates from
handling the radioactive material, and approximate expected gamma spectra. The activity
prediction program is Java-based and uses a quasi-Monte Carlo algorithm which provides results
within minutes as opposed to a full Monte Carlo algorithm which could take days. The activity
prediction program is coupled with Geant 4 and Genie 2000 programs to incorporate the
predicted gamma spectrum. The program was modified to include the plastic clay standard and
approximate pottery sample concentrations based on previous reported research on similar pottery
36
samples [23]. The target and product information, such as thermal neutron cross-section, halflife, and gamma ray energy, was taken from the Lund/LBNL nuclear database [25]. User input
for a simulation includes the sample weight, reactor power, irradiation time, and sample
composition. The program then calculates the sample activity, exposure rate at various distances
and times, and an estimated gamma-ray spectrum.
Sample Irradiation
The pottery samples have a complex composition comprised of many elements. The
radioisotopes produced in these elements via neutron irradiation have a very wide range of halflives varying from minutes to several hundred or possibly even thousands of years. This wide
variety of half-lives necessitates two distinct irradiation and counting times. Short-lived
radioisotopes (t1/2 < 15 hours) require a short irradiation time (on the order of minutes) so that
after a short decay period, the activated sample holder has a low enough radiation dose that the
short-lived radioisotopes can be removed from the holder and measured before they decay away.
The medium and long-lived isotopes require a longer irradiation because they need to be activated
enough such that, after decaying for several days to allow short-lived isotopes to decay away, a
sufficient number of the long-lived isotopes still remain that can be counted. Previous work [23]
determined that total neutron fluences of ~ 6.1 x 1014 neutrons/cm2 (1.7 x 1012 neutrons/cm2 * sec
for 6 min) for the short irradiation and ~ 5.8 x 1017 neutrons/cm2 (2 x 1013 neutrons/cm2 * sec for
8 hours) for the long irradiation were needed to provide sufficient activation and counting
statistics during gamma-ray measurement.
Using the information collected from the activity prediction program and from previous
work [23] the following irradiation schedule was developed to identify short, medium, and longlived radioisotopes in the samples. Each sample is wrapped in aluminum foil and placed in the
sample holder in the order shown in Figure 4.7. The sample holder is then placed in the 2 x 6
37
tube on the core face. The first irradiation was for six minutes at a reactor power of 110 kW,
which corresponds to a predicted thermal neutron flux of ~1.7 x 1012 neutrons/cm2 s, for a total
neutron fluence of ~ 6.1 x 1014 neutrons/cm2. After irradiation the sample holder remains in the 2
x 6 tube for two hours so that very short lived isotopes can decay and the exposure rates from the
activation of the aluminum sample holder decrease sufficiently to handle the samples safely. In
order to minimize radiation exposure while extracting the samples from the sample holder a lead
box was built on a cart and the sample holder was placed into it immediately after removing from
the 2 x 6 tube. The cart was then wheeled to a workstation where more lead shielding and
Plexiglas beta shielding was set up. At the workstation the samples were removed one at a time
from the sample holder in the lead cave using tongs approximately 30 cm in length. The hinge
design of the sample holder greatly enhanced the ease with which the samples could be removed
from the holder. The individual samples were then unwrapped at the workstation and the
activated aluminum foil wrapper placed in a waste bag behind lead shielding and the ampoule
placed in another labelled container used to transport the samples to the counting facilities. After
extricating the samples from the sample holder each sample is then counted with a high purity
germanium detector (HPGe) for 15 minutes. After counting all the samples they are again
wrapped in aluminum foil and placed in the sample holder, which is then placed back in the 2 x 6
tube on the core face.
The second irradiation was for eight hours at a reactor power of 900 kW, which
corresponds to a thermal neutron flux of ~2.0 x 1013 neutrons/cm2 s for a total neutron fluence of
~ 5.8 x 1017 neutrons/cm2. After the long irradiation the sample holder remained in the 2 x 6 tube
for seven days to allow many of the short-lived radioisotopes to decay away and for the exposure
rates from the aluminum sample holder to decrease sufficiently to handle the samples safely. The
samples were removed from the sample holder, prepared for counting using the same procedure
described above and counting began eight days after the end of the irradiation. Each sample was
38
counted for 50 minutes with an HPGe detector (see section 4.2). The samples were counted
again, this time 23 days after irradiation. During this third count the samples were counted for
three hours each. The samples were counted for progressively longer periods of time to ensure
that there were sufficient counts in each of the identifying gamma-ray photopeaks so that each
element could be identified with a reliable statistical confidence.
Both irradiations were performed with the PSBR safety control rod at the upper limit. In
Figure 4.1 the safety control rod is at position F-9 on the core map and is the closest control rod
to the 2 x 6 tube irradiation position. This operating condition helps to flatten the neutron flux
profile and give a more even neutron flux distribution to each of the samples. Operating at this
condition will also slightly increase the thermal neutron flux in the 2 x 6 tube because more
neutrons will reach the 2 x 6 tube instead of being absorbed in the safety control rod.
Section 4.3 mentions the intense gamma ray beam escaping around the edges of the
shield plug in the 2 x 6 tube. During irradiation access directly above the 2 x 6 tube on the
reactor bridge was prevented with signage as well as a physical barrier. Also, the reactor bay roof
was made inaccessible. These safety precautions were taken so as to prevent unnecessary
exposures during experimentation.
This section provides a brief overview of the sample preparation and irradiation
procedures and activity predictions. The full sample and irradiation procedures and activity
predictions are included in Appendix C.
39
4.7 Error Propagation
After calculating the final concentrations in each of the samples an error analysis was
performed. The standard error equation is [3]:
(
)
(
)
(
)
4.6
Where σ represents the error or standard deviation, u is the measured property and u = f(x, y, z
…), and (x, y, z, …) are the parameters that contribute to the total error. Using Equation 2.3 to
determine the concentration of a trace element in the unknown sample, the error associated is
calculated via Equation 4.7:
√(
)
( )
(
)
(
)
4.7
Where w is the concentration of the element in the sample, ϕn is the normalized flux, A is the
decay rate, m is the total mass of the sample, and td is the decay time. The error for the
normalized flux, σϕn, was obtained from the flux profile calculation. The error from the counting
activity, σA, was obtained from the GENIE 2000 data processing output. The errors associated
with mass and decay time were taken as constants, 0.02 g and 60 s respectively.
40
Chapter 5
Experimental Results
The trace element compositions for each of the pottery samples were calculated
according to the procedures given in Chapter 4. The results are displayed in graphical and tabular
form in section 5.2. After calculating the trace element composition, the error associated with
each trace element concentration was calculated as shown in section 4.7.
5.1 Italian Tiles Data Summary
Below in Table 5.1 is a representation of the information given for each sample after
completing the data processing described in Chapter 4. The nuclide column in each of the tables
represents the radioisotope that identified the element in the first column of the table. The
columns ‘> 2 hours’, ‘8 days’, and ‘23 days’ contain the total weight percent of the element in
column one after decay times of 2 hours, 8 days, and 22 days respectively. The weight percent
can be converted to ppm according the following equation:
5.1
The ID Confidence (short for Identification Confidence) column is an output from the Genie 2000
software program and represents the statistical confidence that peaks identified while processing
the a gamma-ray spectrum are indeed the characteristic peaks of that particular nuclide.
Occasionally, one element may be identified by multiple isotopes or from more than one decay
41
period. In these instances, one of the isotopes or decay times typically will have a significantly
higher ID Confidence, and statistically will give the more accurate total weight percent of the
element specified. In rare instances the element may be observed in two or more decay times
with similar ID Confidences, and the decay time with the slightly (< 0.01) higher ID Confidence
may have a significantly different resulting concentration. In these rare cases preference was
given to the concentration from the decay time when the element was expected to be most
accurately determined because this is the period with the highest probability of the least
interference from nearby gamma ray photo peaks in the gamma ray spectra. Also, in the element
column some of the elements are demarcated by an asterisk. The asterisk is denoting those
elements whose concentration was not certified by the plastic clay standard. The elements that
are certified in the standard were determined by two or more material characterization methods.
The certified concentration value is a weighted mean of all the characterization techniques used to
determine the certified element. The non-certified elements were determined by only one method
and error bounds were not given for those elements [44].
Table 5.1. Sample 147B Trace Element Composition.
42
A summary of the trace element concentration for all the Italian tile samples is given in Table 5.2.
If a particular element has concentration values determined via multiple decay periods, then only
the concentration with the highest ID Confidence is given in Table 5.2. A complete summary,
such as displayed in Table 5.1, for each element can be found in Appendix D. An example of the
gamma spectra obtained for each of the samples is given in Figure 5.1. Figure 5.1 is the
corresponding gamma ray spectrum associated with Table 5.1. From these gamma ray spectra all
the data processing and analysis were performed that yielded the results shown in Tables 5.1 and
5.2.
43
Table 5.2. Trace Element Concentrations.
Sample
Sodium
Potassium
Manganese
Strontium
Europium
Scandium
Titanium
Chromium
Iron
Zinc
Rubidium
Antimony
Barium
Hafnium
Calcium
Zirconium
139B
6.99E-03
3.09E-02
1.14E-03
6.20E-04
1.884E-06
1.29E-05
X
9.31E-05
3.66E-02
1.12E-04
1.11E-04
2.58E-06
9.91E-04
4.74E-06
X
2.67E-04
140B
6.46E-03
2.82E-02
1.19E-03
4.49E-04
1.90E-06
1.36E-05
X
1.08E-04
5.64E-02
1.42E-04
1.57E-04
2.55E-06
4.98E-04
4.38E-06
4.07E-04
2.89E-04
141B
9.71E-03
4.07E-02
1.05E-03
6.65E-04
2.04E-06
3.00E-05
X
8.62E-05
3.72E-02
1.70E-04
1.60E-04
5.72E-06
3.76E-04
5.59E-06
X
2.72E-04
142B
1.34E-02
3.90E-02
1.03E-03
7.14E-04
1.89E-06
1.40E-05
6.74E-03
8.49E-05
4.23E-02
1.24E-04
2.39E-04
3.11E-06
5.24E-04
4.83E-06
1.71E-04
3.11E-04
143B
8.23E-03
1.42E-02
1.04E-03
7.60E-04
2.19E-06
1.20E-05
1.07E-02
8.02E-05
3.88E-02
1.20E-04
2.08E-04
2.71E-06
2.22E-04
5.43E-06
X
3.13E-04
144B
8.36E-03
2.83E-02
9.30E-04
8.30E-04
2.07E-06
1.37E-05
8.87E-03
1.15E-04
4.99E-02
2.12E-04
1.74E-04
3.21E-06
8.50E-04
6.25E-06
5.55E-04
3.21E-04
145B
8.69E-03
2.67E-02
1.10E-03
1.04E-03
1.88E-06
3.36E-05
7.19E-02
1.02E-04
2.26E-02
6.16E-05
1.52E-04
3.01E-07
3.92E-04
4.59E-06
X
3.03E-03
146B
8.06E-03
2.06E-02
1.08E-03
7.30E-04
1.75E-06
1.20E-05
X
1.13E-04
3.59E-02
8.51E-05
1.21E-04
2.78E-06
6.35E-04
5.91E-06
6.90E-04
1.95E-04
147B
5.56E-03
2.59E-02
4.53E-04
5.40E-04
1.65E-06
1.13E-05
X
7.93E-05
3.12E-02
1.46E-04
1.51E-04
3.24E-06
1.50E-03
5.06E-06
1.58E-03
4.69E-04
148B
6.83E-03
3.06E-02
8.51E-04
6.29E-04
1.98E-06
1.04E-05
X
8.43E-05
3.41E-02
1.28E-04
1.76E-04
6.10E-07
2.63E-04
5.38E-06
3.89E-04
4.62E-04
149B
7.30E-03
5.50E-02
1.20E-03
1.07E-03
2.965E-06
3.02E-05
X
5.78E-05
4.84E-02
1.51E-04
3.16E-04
3.26E-07
2.10E-04
7.45E-06
X
5.35E-04
150B
3.84E-03
1.97E-02
1.05E-03
X
3.71E-06
7.28E-06
X
6.87E-05
4.85E-02
1.75E-04
5.47E-04
5.59E-07
2.83E-04
8.04E-06
2.24E-04
6.04E-04
151B
4.38E-03
1.61E-02
1.56E-03
1.04E-03
3.89E-06
4.71E-06
X
6.90E-05
5.21E-02
1.25E-04
4.24E-04
4.84E-07
6.43E-05
9.02E-06
X
7.03E-04
152B
5.87E-03
2.22E-02
3.12E-03
X
4.902E-06
1.14E-05
X
1.18E-04
6.42E-02
2.05E-04
4.82E-04
1.53E-07
2.65E-03
1.04E-05
X
8.50E-04
153B
3.73E-03
2.41E-02
2.03E-03
X
3.997E-06
1.04E-05
X
7.30E-05
6.04E-02
2.00E-04
5.73E-04
8.84E-07
1.96E-04
1.10E-05
X
7.37E-04
44
Figure 5.1. An example gamma spectra that was obtained from counting sample 147B.
45
5.2 Quality Control Data
An important aspect of CNAA is verifying that the standard(s) used as comparators do in
in fact contain the listed trace elements in the amounts specified by the certifying agency. For
this project, verification was achieved by irradiating a second standard and calculating the trace
element composition by comparison with the first standard. The Brick Clay SRM obtained from
NIST [45] was used as the quality control for this research due to its similarity to the plastic clay
standard that was used as the comparator for the pottery samples. Some of the trace elements in
the standards that are used in CNAA are not certified, meaning they have only been determined
by one analytical method. Using a quality control establishes a baseline by which the
comparative results can be compared, especially for the non-certified trace elements. In general
our results showed a wider variation between the non-certified trace element concentrations of the
standard and quality control than between the trace elements that were certified.
In order to eliminate as many variables as possible, the plastic clay SRM was placed next
to the quality control SRM in the sample holder for each irradiation and also counted and
analyzed sequentially to minimize any errors that might arise from varying decay times. The data
for one of the quality control samples is shown in Table 5.3. Table 5.3 includes the element and
nuclide analyzed, the NIST concentration specified in the SRM certificate, the sample trace
element concentration obtained through CNAA, and the percent difference between the
experimental and specified trace element concentrations. In Table 5.3 some of the elements are
demarcated by an asterisk. As previously stated these are trace elements that were not certified.
Also zirconium is listed in the table without a corresponding sample concentration and percent
difference. This is because there is zirconium in the quality control standard but none detected in
the comparator standard for the pottery samples. There are a handful of elements that are present
46
in either the comparator standard or the quality control standard but not the other. A table for each
of the quality control samples is included in Appendix D.
Table 5.3. A Summary of Quality Control Sample #4.
Element
Sodium
Silicon
Potassium
Manganese
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Zirconium*
Nuclide
Na-24
Si-31
K-42
Mn-56
Eu-152m
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Ba-131
Hf-181
Zr-95
NIST Specified
Concentrations
1.30E-03
2.43E-01
2.43E-02
1.73E-03
1.90E-06
2.25E-05
1.10E-04
9.05E-02
1.50E-04
1.90E-04
7.15E-07
4.32E-04
4.60E-06
1.45E-04
Actual Sample
Concentrations
1.43E-03
3.35E-01
2.53E-02
2.10E-03
2.38E-06
2.27E-05
1.11E-04
9.48E-02
1.36E-04
2.09E-04
1.22E-06
5.71E-04
4.50E-06
NA
Percent Difference
-9.51
-37.62
-3.87
-21.27
-25.23
-0.79
-0.99
-4.78
9.31
-10.01
-71.14
-32.06
2.21
NA
Some of these elements have a significant difference between the NIST specified
concentration and the actual sample concentration that was measured. For the most part these are
elements that are not certified (i.e. they were previously only determined by one analysis method)
with exception of silicon. Silicon is the major component of the quartz ampoule that was used to
encapsulate all the samples. Therefore it was expected that silicon concentration would differ
significantly from sample concentrations. Also silicon was not one of the trace elements
identified to be used in determining the provenance of these samples and therefore was not
corrected for. Many of the remaining elements have very small concentrations (ppm range) thus
even small variations can have a significant effect on the percent difference. However, the NIST
specified or certified values and the actual values obtained through experimentation are all of the
same magnitude.
47
Chapter 6
Analysis of CNAA Results
When performing neutron activation analyses for archaeological studies the primary goal
is usually to determine the provenance of the archaeological sample(s). Previously, this type of
analysis consisted of determining whether a couple of elements from a few samples were within a
certain percentage of a standard deviation from one another [29]. Some more modern techniques
include sophisticated statistical programs that use multivariate techniques to analyze hundreds of
samples from several different origins and can plot the information in three dimensions [31].
This research included only 15 samples from two sites within a small geographical area. Analysis
was performed using mean character differences and scatter plots to determine provenance for
these pottery samples.
Calculating the Mean Character Difference (MCD) and Squared Mean Euclidean
Distance (SMED) from the information given in Table 5.2 is used to begin grouping the pottery
samples with similar provenances. The MCD is given in Equation 6.1:
∑|
|
6.1
where n is the number of trace elements, Ai and Bi are the log concentrations of the ith element in
pottery samples A and B respectively. The SMED is given in Equation 6.2:
48
∑
6.2
where the symbols are defined the same as in Equation 6.1. The MCD is used to determine
clusters or groups within a sample set and the SMED is a good indicator of the variance between
samples in that cluster or group [39]. Using equation 6.1 to evaluate the samples and looking at
scatter plots of important trace element compositions it appears that there are two distinct groups:
Group 1 includes samples 139B-148B, Group 2 includes samples 149B-153B. A sample of the
MCD grouping data is displayed in Table 6.1 with the full table found in Appendix D. The
important trace elements used in the scatter plots include europium, chromium, hafnium,
scandium, rubidium, and zirconium. Three scatter plots are given in Figures 6.1-6.3 with a more
comprehensive set given in Appendix D.
Table 6.1. MCD Grouping Data for the Pottery Samples.
Sample
139B
140B
141B
142B
143B
144B
145B
146B
147B
148B
149B
150B
151B
152B
153B
MCD
0.0817
0.0817
0.1397
0.1024
0.1298
0.1043
0.2005
0.0786
0.1209
0.1490
0.2917
0.3047
0.3664
0.3746
0.3320
Group
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
49
Sodium and Potassium
6.0E-02
Potassium [mg/kg]
5.0E-02
4.0E-02
3.0E-02
2.0E-02
1.0E-02
0.0E+00
0.0E+00 2.0E-03 4.0E-03 6.0E-03 8.0E-03 1.0E-02 1.2E-02 1.4E-02 1.6E-02
Sodium [mg/kg]
Figure 6.1. A scatter plot that shows the sodium and potassium trace element compositions of the
tile samples. No distinct groups are found.
Figure 6.1 is a scatter plot of two of the trace elements that were determined in the analysis of the
tile samples. As shown in the plot there is no distinct grouping that is noticeable amongst the tile
samples. These two elements do not contribute significantly to the grouping of the tile samples.
Figure 6.2 is a scatter plot of the europium and chromium trace element compositions of the tile
samples. Two distinct groups can be seen in this plot and the MCD and SMED analysis confirm
these groups. Hafnium and chromium appear to have the primary defining influence in
determining Group 1 while europium and rubidium fulfill the same role for inclusion in Group 2.
50
Europium and Chromium
1.4E-04
Chromium [mg/kg]
1.2E-04
1.0E-04
8.0E-05
6.0E-05
4.0E-05
2.0E-05
0.0E+00
0
0.000001 0.000002 0.000003 0.000004 0.000005 0.000006
Europium [mg/kg]
Figure 6.2. A scatter plot of the europium and chromium trace element compositions for the tile
samples. Two distinct groups appear.
Rubidium and Zirconium
3.5E-03
Zirconium [mg/kg]
3.0E-03
2.5E-03
2.0E-03
1.5E-03
1.0E-03
5.0E-04
0.0E+00
0.0E+00 1.0E-04
2.0E-04
3.0E-04
4.0E-04
5.0E-04
6.0E-04
7.0E-04
Rubidium [mg/kg]
Figure 6.3. A scatter plot of the rubidium and zirconium trace element compositions for the tile
samples. The outlier is from sample 145B.
51
Figure 6.3 shows a very strong outlier in the zirconium concentration of sample 145B. Zirconium
was one of the elements not verified by the quality control and this outlier was strong enough to
move sample 145B into group 2. However, based on many other scatter plots it is apparent that
sample 145B still belongs in group 1. It is possible that this particular sample may have an
extraordinary amount of zirconium, or that the analysis is incorrect. After the samples are
grouped, Equation 6.2 is used to evaluate the variance of the samples within those groups. A
small sampling of the SMED is included in Table 6.2 with the full table available in Appendix D.
Table 6.2. SMED Group Variance Data for the Pottery Samples.
Sample
139B
140B
141B
142B
143B
144B
145B
146B
147B
148B
149B
150B
151B
152B
153B
SMED Group
0.0134
1
0.0134
1
0.0381
1
0.0216
1
0.0459
1
0.0150
1
0.1078
1
0.0094
1
0.0235
1
0.0610
1
0.1407
2
0.1323
2
0.2184
2
0.2304
2
0.1488
2
The SMED is used to evaluate the appropriateness of each group, thus mean and standard
deviation of the SMED were used to evaluate the members of each group.
52
Table 6.3. Group 1 Statistics.
Group 1
Mean
0.03731
σ
0.03142
± 1σ
0.0059 ± 0.0687
± 2σ
0 ± 0.1002
± 3σ
0 ± 0.1316
Table 6.4. Group 2 Statistics.
Mean
σ
± 1σ
± 1.5σ
± 2σ
± 3σ
Group 2
0.1741
0.0465
0.1277 ± 0.2206
0.1044 ± 0.2438
0.0812 ± 0.2670
0.0346 ± 0.3135
Tables 6.3 and 6.4 show the resulting statistical analysis of the groups formed from dividing the
samples. Nearly all of the samples in Group 1 are within two standard deviations from the mean
and none of the samples from Group 2 lie within three standard deviations from the mean of
Group 1. This indicates that there is a 95% probability that the samples included in Group 1 are
indeed part of the same group. Simultaneously, there is less than 1% probability that any of the
Group 2 samples are part of Group 1. Similar results are found from Group 2 with all samples
within 1.5 standard deviations from the mean and no samples from Group 1 lying inside of 1.5
standard deviations from the mean of Group 1. This indicates less than 20% probability of
inclusion in Group 2 for a couple of these samples (145B and 148B) and less than 1% probability
of inclusion in Group 2 for the remaining Group 1 samples [47].
53
Chapter 7
Conclusions and Future Work
This research analyzed the composition of 15 Italian tile samples whose trace element
composition was unknown. Several important procedures and tools were developed in the
process of completing the analysis of these samples. A process was developed for sealing tile
samples and other powdered samples in quartz encapsulation. This encapsulation method is ideal
for many reasons including: the ability to maintain integrity after long irradiation times,
negligible contributions to the overall activity of the sample, a reduction in the likelihood of cross
contamination or of spreading radioactive contamination. A sample holder was made that allows
for irradiation of up to 28 samples with neutron fluxes that are relatively similar. There were two
irradiations performed for this work. The first irradiation was a short irradiation for 6 minutes
with a thermal neutron flux of ~ 1.7 x 1012 neutrons/cm2 s. The second irradiation was much
longer, lasting eight hours with a corresponding thermal neutron flux of ~ 2.0 x 1013
neutrons/cm2s. This sample holder is rugged and can be used for many irradiations and the
irradiation location in the 2 x 6 tube is ideal for the repeatability of future experiments.
The 15 samples were divided into two groups based on the trace element compositions
that were determined through CNAA experiments. Between 13 and 16 trace elements were
determined for each sample with concentrations ranging from parts per million (ppm) to
milligrams per gram including: sodium (1-10 mg/g), potassium (14-55 mg/g), manganese (0.5-3
mg/g), strontium (0.5-1.1 mg/g), europium (1-5 ppm), scandium (4-34 ppm), titanium (6-70
mg/g), chromium (60-120 ppm), iron (23-64 mg/g), zinc (62-212 ppm), rubidium (0.1-0.6 mg/g),
antimony (0.15-5.7 ppm), barium (64 ppm-2.7 mg/g), hafnium (4.3-11 ppm), calcium (0.17-1.6
54
mg/g), and zirconium (0.2-3 mg/g). The individual concentrations for each sample are given in
Table 5.2 and in Appendix D. The first group is composed of samples 139B-148B and the
provenance of that group is likely Tarquinia based on comparison with previous work. The
second group is composed of samples 149B-153B and the provenance of that group is likely Veii
also based on comparison with previous work. These groupings were determined using
multivariate analysis techniques such as Mean Character Difference and Squared Mean Euclidean
Distance and with scatter plots of concentrations of important trace elements found in the
samples. The most useful scatter plots had either europium or chromium as one of the trace
elements. The plots generated with one of these elements generally produced two distinct groups.
However plots including zirconium consistently showed sample 145B belonging to a group that is
neither group 1 or group 2. Zirconium was not one of the elements in the standard verified by the
quality control reference material. Thus assuming that the specified zirconium concentration for
the standard used to compare with sample 145B may not be a valid assumption. However, this is
unlikely because the same standard was used to compare multiple samples. Other explanations
for the anomalous zirconium concentration in sample 145B include possible cross contamination
or an unusually high congregation of zirconium in that sample.
Overall NAA and in particular CNAA is a satisfactory method for determining the trace
element concentrations in these unknown tile samples. Using the comparative method allowed
for simpler, more succinct data analysis as opposed to using the absolute method where every
minute characteristic of the reactor, irradiation and counting sequence would have to be
determined. Another advantage of CNAA in this work is the robustness of the sample holder and
method that would allow many more samples to be irradiated and compared across multiple
irradiations. An alternative to NAA that is occasionally used is ICP-MS. However, prepping
samples for ICP-MS involves labor intensive acid dissolutions with very corrosive acids. ICP-MS
will increase the accuracy of the trace element concentrations determined for the samples, but at
55
the cost of significantly more time and by destruction of the sample itself. NAA may give
slightly less accurate results but is efficient and much more appropriate for determining many
trace element concentrations in large numbers of samples.
Several areas of improvement were identified for future pottery or tile sample NAA
irradiations in the 2 x 6 tube. The neutron flux profile of the sample holder in this irradiation
location was characterized for the reactor operating with the safety control rod at its upper limit.
The thermal neutron flux in this operating mode was higher than expected, but there was also an
unexpected depression in the profile and the magnitude of the neutron flux varied by ~30 %
between the top and bottom rows of the sample holder, although the shape of the profile was
consistent between similar locations in the top and bottom rows. The neutron flux profiles in this
sample holder while operating the reactor without the safety control rod at the upper limit should
be evaluated and compared to determine if the neutron flux profile across the sample is more
uniform in one condition or the other. Another source for refinement in this process is the
selection of a different standard or perhaps developing a specialized standard similar to previous
work. Since there are multiple elements that are not certified, finding a standard with more
certified elements would increase the statistical certainty of the composition of samples being
analyzed. Initially larger emphasis was placed on the background matrix of the standard as
opposed to the verifiability of the trace elements. In choosing a future standard greater emphasis
should be placed on finding a standard with most or all of the elements certified with minor
concerns about the background matrix matching the samples. Alternative solutions include using
multiple standards to provide a quality control for the standard used in the comparison method
with the unknown sample. Another avenue that would be worthwhile to investigate is using the
k0 NAA method, which is another CNAA method that compares all elements to a single
comparator, typically a gold wire. The gold wire is very small and could theoretically be placed
alongside each of the samples in the sample holder. This would increase the number of samples
56
that needed to be counted but it would also eliminate the need to apply a flux correction factor.
This method would have drawbacks with respect to its accuracy in determining certain elements
such as europium and there may be other problems regarding the multiple counting sequences,
but it bears further investigation.
57
References
1. A. J. Ammerman, I. Iliopoulos, F. Bondioli, D. Filippi, J. Hilditch, A. Manfredini,
L. Pennisi, N. A. Winter, “The clay beds in the Velabrum and the earliest tiles in
Rome,” Journal of Roman Archaeology, vol. 21, pp. 7-30, 2008.
2. N. A. Winter, I. Iliopoulos, A. J. Ammerman, “New light on the production of
decorated roof of the 6th c. B.C. at sites in and around Rome,” Journal of Roman
Archaeology, vol.22, pp. 6-28, 2009.
3. J.R. Lamarsh, “Introduction to Nuclear Engineering,”Addison-Wesley Publishing
Company Inc., 1983.
4. M.D. Glascock, “Tables for Neutron Activation Analysis,” The University of
Missouri, 3rd edition, 1991.
5. D. Sahin, “Tracing Footprint of Environmental Events in Tree Ring Chemistry
Using Neutron Activation Analysis,” PhD Dissertation, Department of
Mechanical and Nuclear Engineering, The Pennsylvania State University,
University Park, PA, USA, 2012.
6. T. Bereznai, “Methods, Problems and Trends of Standardization in Multi-element
Reactor Neutron Activation Analysis”, Fresenius Journal of Analytical Chemistry,
302, pp. 353-363, 1980.
7. C.M. Ryan, C.M. Marianno, W.S. Charlton, W.D. James, “Neutron Activation
Analysis of Concrete for Cross-border Nuclear Security,” Journal of
Radioanalytical and Nuclear Chemistry, 291, pp. 267-272, 2012.
58
8. F. Girardi, et al., “Reactor Neutron Activation Analysis by the Single Comparator
Method,” Analytical Chemistry, 37(9), pp. 1085-1092, 1965.
9. A. Simonits, F. De Corte, J. Hoste, “Single-Comparator Methods in Reactor
Neutron Activation Analysis,” 24, pp. 31-46, 1975.
10. F. De Corte, “The Standardization of Standardless NAA,” Journal of
Radioanalytical and Nuclear Chemistry, 248(1), pp. 13-20, 2001.
11. A. Yavar, et al., “Development and Implementation of Høgdahl Convention and
Westcott Formalism for k0-INAA Application at Malaysian Nuclear Agency
Reactor,” Journal of Radioanalytical and Nuclear Chemistry, 291, pp. 521-527,
2012.
12. “The Penn State Breazeale Reactor: A Facility for the Past, Present, and Future of
the Pennsylvania State University,” 1993. [Online] Available:
http://www.rsec.psu.edu/pages/home/history/rsecHISTORY.pdf
13. G.C. Geisler, “Design Manual and Safety Analysis of the Penn State TRIGA
Reactor, Nuclear Reactor Facility,” The Pennsylvania State University, 1965.
14. V. Karriem, “PSBR Core Design Studies of the D2O Tank Design and New LEU
Fuel Utilization,” Thesis for M. Sc., The Pennsylvania State University,
University Park, PA, USA, 2011.
15. K. B. Kelly, “Implementation of the k0—Standardization Method at the Penn
State Breazeale Reactor,” Thesis for M. Sc., The Pennsylvania State University,
University Park, PA, USA, 2013.
59
16. R. M. Keyser, T.R. Twomey, D. Gunter, “Performance of a Low-Background
High Purity Germanium Detector with a Novel EndCap,” 2006. [Online].
Available: http://www.ortec-online.com
17. T. Daubenspeck, “Flux Charactarization Report”, Penn State Breazeale Reactor,
October, 1995.
18. ASTM International, “Standard Practice for Determining Neutron Fluence,
Fluence Rate, and Spectra by Radioactivation Techniques”, Designation E 26103, pg. 1-10, 2003.
19. ASTM International, “Standard Test Method for Determining Thermal Neutron
Reaction and Fluence Rates by Radioactivation Techniques”, Designation E 26203, pg. 1-9, 2003.
20. Martinho, E., Goncalves, I. F., Salgado, J., “Universal curve of epithermal
neutron resonance self-shielding factors in foils, wires and spheres”, Applied
Radiation and Isotopes, 56, pg. 371-375, 2003.
21. Martinho, E., Salgado, J., Goncalves, I. F., “Universal curve of the thermal
neutron self-shielding factor in foils, wires, spheres and cylinders”, J.
Radioanalytical and Nuclear Chemistry, Vol 261, No. 3, pg. 637-643, 2004.
22. S. G. Pomme, et al., “Method for the Determination of Neutron Field Monitor
Burnup Effects by Gamma-spectrometry”, Analytical Communications, 34, pg.
133-135, 1997.
23. Perlman, I., Asaro, F., “Pottery Analysis By Neutron Activation”, Archaeometry
11:21-52, 1969.
60
24. D. Sahin, “Activity, Exposure Rate and Gamma Spectrum Prediction For Neutron
Irradiated Materials at Radiation Science and Engineering Center,” M. Sc. thesis
in Mechanical and Nuclear Engineering, Penn State University, 2008.
25. Lawrence Berkeley National Laboratory, “Lund/LBNL Nuclear Data Search,”
Lund/LBNL Nuclear Data Search; Online source,
http://nucleardata.nuclear.lu.se/nucleardata.toi/.
26. http://www.wilmadlabglass.com/uploadedFiles/Main_Site/Pages/Support/Heraeus_Quartz_Properties
.pdf
27. G. Hevesy, H. Levi, “Artificial Radioactivity of Dysprosium and other Rare Earth
Elements,” Nature, Vol. 136, pp. 103, 1935.
28. E.V. Sayre, A.W. Dodson, “Neutron Activation Study of Mediterranean
Potsherds,” American Journal of Archaeology, Vol. 61, No.1, pp. 35-41, 1957.
29. V.M. Emeleus, “The Technique of Neutron Activation Analysis Applied to Trace
Element Determination in Pottery and Coins,” Archaeometry, Vol. 1, pp. 6-15,
1958.
30. V.M. Emeleus, G Simpson, “Neutron Activation Analysis of Ancient Roman
Potsherds,” Nature, Vol. 185, pp. 196, 1960.
31. M.D. Glascock, H. Neff, “Neutron Activation Analysis and Provenance Research
in Archaeology,” Measurement Science & Technology, Vol. 14, No. 9, pp. 15161526, 2003.
61
32. K.J. Vaughn, H. Neff, “Moving Beyond Iconography: Neutron Activation
Analysis of Ceramics from Marcaya, Peru, an Early Nasca Domestic Site,”
Journal of Field Archaeology, Vol. 27, pp. 75-90, 2000.
33. T.L. Bray, et. Al., “A Compositional Analysis of Pottery Vessels Associated With
the Inca Ritual of Capacocha,” Journal of Anthropological Archaeology, Vol. 24,
pp. 82-100, 2005.
34. T.P. Harrison, R.G.V. Hancock, “Geochemical Analysis and Sociocultural
Complexity: A Case Study From Early Iron Age Megiddo (Israel),”
Archaeometry, Vol. 47, No. 4, pp. 705-722, 2005.
35. S.C. Phillips, M. Morgenstein, “A Plains Ceramic Clay Source Characterization
by Comparative Geochemical and Petrographic Analyses: Results from the
Calhan Paint Mines, Colorado, U.S.A.,” Geoarchaeology-An International
Journal, Vol. 17, No. 6, pp. 579-599, 2002.
36. D. Mitchell, et. Al., “Geochemical Characterisation of North Asian Glazed
Stonewares: A Comparative Analysis of NAA, ICP-OES, and Non-destructive
pXRF,” Journal of Archaeological Science, Vol. 39, pp. 2921-2933, 2012.
37. R.W. Jamieson, et. Al., “Neutron Activation Analysis of Inca and Colonial
Ceramics from Central Highland Ecuador,” Archaeometry, Vol. 55, No. 2, pp.
198-213, 2013.
38. A. Hein, et. Al., “Standardisation of Elemental Analytical Techniques Applied to
Provenance Studies of Archaeological Ceramics: An Inter Laboratory Calibration
Study,” The Analyst, Vol. 127, pp. 542-553, 2002.
62
39. A.M. Bieber, et. Al., “Application of Multivariate Techniques to Analytical Data
on Aegean Ceramics,” Archaeometry, Vol. 18, No. 1, pp. 59-74, 1976.
40. J.C. Davis, “Statistics and Data Analysis in Geology,” Wiley, New York, 1986.
41. M.J. Baxter, “Exploratory Multivariate Analysis in Archaeology,” Edinburgh
University Press, Edinburgh, 1994.
42. M.D. Glascock, “Characterization of Archaeological Ceramics at MURR by
Neutron Activation Analysis and Multivariate Statistics Chemical
Characterization of Ceramic Pastes in Archaeology,” ed. H. Neff, Prehistory
Press, Madison, 1992.
43. R.T. Ratner, W.G. Vernetson, “Multielement Comparison of Instrumental
Neutron Activation Analysis Techniques Using Reference Materials,” Journal of
Radioanalytical and Nuclear Chemistry, Articles, Vol. 192, No. 2, pp. 351-359,
1995.
44. Standard Reference Material 98b – Plastic Clay; National Bureau of Standards,
U.S. Department of Commerce, Gaithersburg, MD, 1988.
45. Standard Reference Material 679—Brick Clay, National Bureau of Standards,
U.S. Department of Commerce, Gaithersburg, MD, 1987
46. V.M. Emeleus, “The Technique of Neutron Activation Analysis Applied to Trace
Element Determination in Pottery and Coins,” Archaeometry, Vol. 1, pp. 6-15,
1958.
47. D.C. Montgomery, G.C. Runger, N.F. Hubele, “Engineering Statistics 3rd ed.,”
Wiley, New Jersey, 2006.
63
Appendix A
Physical Specifications
The HPGe detector dimensions provided by the manufacturer are displayed in Figure A.1.
Figure A.1. HPGe detector dimensions provided by the manufacturer.
64
Figure A.2 is a schematic of the 2 x 6 tube and its position in the PSBR.
Figure A.2. A diagram of the PSBR core and 2 x 6 tube fixture coupling to the core [17].
65
Appendix B
NIST Certificates
The following is the NIST certificate for the plastic clay that was used as a reference
standard during the trace element determination.
66
67
The following certificate is the NIST certificate for quality control standard.
68
69
Appendix C
Procedures
Test Instruction:
Gold Wire Flux Calculation Irradiation in 2 x 6 Tube
Date: November 5, 2012
Author: Chad Durrant
Equipment
Gold Wires (28)
Cadmium Foil Wrappers (14)
Quartz Ampoules (28)
2 x 6 tube Sample Holder
Plastic Ampoule Sample Holder(s)
Polyethylene Counting Tubes (28)
Wire Cutter
Pliers
Ethanol
Paper Towels
Aluminum Foil
Sample Preparation
1. Label 28 polyethylene counting tubes and then place into the plastic sample
holder shown in Figure 1.
2. Cut and weigh 28 gold wires.
3. Wrap every other ampoule in Aluminum Foil and label accordingly (1, 3, 5, etc).
4. Place the remaining wires into a Cadmium sleeve, crimp the ends, then wrap in
Aluminum Foil and label accordingly (2, 4, 6, etc).
5. Place each wire-foil combination into a tube of the 2 x 6 tube sample holder
beginning at the top left and moving left to right, top to bottom. The last sample
should therefore be placed in the bottom right corner of the sample holder.
70
Figure 2: The Plastic Sample Holder
Irradiation
1. Inform the SRO at least two days in advance that 2 x 6 tube will be used for an
irradiation and coordinate to restrict access to the roof of the reactor bay and
reactor bridge.
2. Insert the sample holder (see Figures 2 and 3) into the 2 x 6 tube and attach to the
face of the reactor core.
3. Irradiate the sample at 300 kW with the safety control rod at the upper limit in the
2x6 tube for 20 minutes.
4. Since there must be a ramp up, acquire as accurately as possible the power level
and corresponding time during irradiation.
5. Store in the reactor pool for 72 hours before extracting sample holder.
6. See Flux Irradiation Proposal for notes on activity predictions and exposure.
71
Figure 3: The 2 x 6 tube sample holder
opened
Figure 4: The sample holder
Post-Irradiation
1. Before the sample holder is pulled out of the 2 x 6 tube set up a work area off to
the side in the reactor bay. The work area will include appropriate shielding with
lead bricks and necessary tools. Also have the necessary disposal bins available.
2. Wait for EHS approval and then the sample holder is pulled out of the 2 x 6 tube
and placed in a lead cave on a cart and brought to the work area and placed in the
work area.
3. The pin is pulled and the hinge is lowered so that the foil-wrapped ampoules are
accessible.
4. Extract each wire-foil combination one at a time with tweezers, unwrap the
aluminum and un-crimp the cadmium sleeve (if necessary and place in the used
cadmium container) and place each wire in the correspondingly labeled polyvial
in the plastic sample holder.
5. Once all the wires have been extracted to the plastic sample holder, carry down to
room 2A to begin counting.
6. Use the Sample Changer Application software on the computer and start a batch
run.
7. Before counting the samples, document in the sample changer Run Log the date
and time (according to the acquisition computer) or irradiation and the names of
the samples and Radioisotope ID#.
8. Run the sample changer while counting each sample for the specified time (15
minutes).
72
9. To run a batch, select Sample Changer -> Run Batch. Follow the prompts from
the wizard.
10. Enter the user name, date and time.
11. When entering the batch title do not use spaces. As an example, a wire sample
could be named 1-Gold, representing a gold wire in position 1 of the sample
holder. Enter the batch ID. The batch ID is the type of irradiation: bare or
covered (representing if the gold wire was covered with a cadmium foil). For
example if the batch title is 1-Gold and the batch ID is bare, than Genie will save
the spectrum files to C://Genie2000/camfiles/1-G_bare.
12. Enter the counting time in seconds (e.g. 1 hour = 3600 seconds).
13. The cycle will begin when the user hits OK.
14. After measurement is completed
a. Use the Analysis -> Edit Sample Info to update sample weights and
irradiation information.
b. Use Analysis -> Sample Analysis to perform calculation.
c. Print out the analysis results and place them in the pottery lab notebook.
d. Save copies of spectrum files.
Plastic Clay Short Irradiation
Neutron Activation Activity Prediction Authorization
November 16, 2012
Chad Durrant
Objective: The purpose of this test is to irradiate 6 plastic clay standard reference
materials (SRMs) to determine the approximate spectra that will be obtained as well as to
corroborate predictions that this will be a good SRM for comparative neutron activation
analysis. This is a short irradiation that will help determine shorter-lived isotopes, while a
second longer irradiation will determine longer lived isotopes.
Proposal: ~0.6 g total weight of Plastic Clay SRMs are sealed in 6 quartz ampoules and
wrapped in aluminum foils. 0.005 g total weight of AuAl wires are sealed in 2 quartz
ampoules; one of these is wrapped in a cadmium foil (total cadmium weight ~1 g). The
total weight of the quartz ampoules will be approximately 11.25 g. All of the quartz
ampoules will be placed in the 2 x 6 sample holder and irradiated in the 2 x 6 tube located
on the reactor core face. The sample holder is approximately 100 g of Al 6061 (lower
purity Al) and 160 g of Al 1100 (high purity Al). The sample will be irradiated for 6
minutes at about 110 kW with the safety control rod at the upper limit position. This will
give an approximate total thermal fluence of about 1.7 x 1012, total fast fluence of about
4.4 x 1011, and a resonance fluence of about 8.8 x 1010.
Activity Predictions: The following is a table with the prediction for the total amount of
activity for the samples the and 2 x 6 tube sample holder for up to four hours after
irradiation.
73
Time
0 hrs
1 hrs
2 hrs
3 hrs
4 hrs
Gold
wires
1.02E0
1.64E-3
1.27E-3
1.01E-3
8.14E-4
Quartz
7.23E0
3.65E-1
2.80E-1
2.15E-1
1.65E-1
Plastic
Clay SRM
1.78E+01
3.44E-02
2.70E-02
2.24E-02
1.88E-02
Activity (mCi)
Air
Holder
Al 1100
8.96E-3 3.22E4
6.13E-3 1.45E1
4.20E-3 1.10E1
2.88E-3 8.80E0
1.97E-3 7.12E0
Holder
Al 6061
1.96E4
9.29E0
7.04E0
5.67E0
4.61E0
Cd foil
covers
7.94E-1
3.54E-1
2.01E-1
1.37E-1
1.08E-1
Total
5.18E4
2.46E1
1.86E1
1.48E1
1.20E1
The predicted exposure values are calculated respectively for distances 30 cm and 50 cm
away from the irradiated materials. The following two tables show the total exposure
rates for the samples at 30 and 50 cm respectively. It is anticipated that the sample holder
will be pulled from the 2 x 6 tube after 2 hours and transferred to a shielded work area in
the reactor bay. In the work area the quartz ampoules will be taken out of the aluminum
sample holder and placed into a plastic holder that will be used to transfer the samples for
counting.
Time
0 hrs
1 hrs
2 hrs
3 hrs
4 hrs
Gold
wires
3.28E2
2.00E-2
1.07E-2
8.46E-3
6.78E-3
Quartz
Gold
wires
7.19E1
6.07E-3
3.66E-3
2.87E-3
2.28E-3
Quartz
2.27E3
7.62E1
5.85E1
4.49E1
3.44E1
Time
0 hrs
1 hrs
2 hrs
3 hrs
4 hrs
4.98E2
1.65E1
1.26E1
9.69E0
7.44E0
Exposure (mrem/hr) 30 cm
Plastic
Air
Holder Holder
Clay SRM
Al 1100 Al 6061
5.70E3
5.93E-2
1.04E7
6.29E6
3.36E0
3.91E-2
3.54E2
2.30E2
2.64E0
2.68E-2
1.25E2
8.20E1
2.17E0
1.83E-2
1.02E2
6.67E1
1.81E0
1.26E-2
8.58E1
5.59E1
Cd foil
covers
3.39E0
1.05E0
5.13E-1
3.42E-1
2.70E-1
Exposure (mrem/hr) 50 cm
Plastic
Air
Holder Holder
Clay SRM
Al 1100 Al 6061
1.25E3
5.93E-2
3.73E6
2.26E6
7.45E-1
3.91E-2
1.27E2
8.27E2
5.86E-1
2.68E-2
4.51E1
2.95E1
4.83E-1
1.83E-2
3.67E1
2.40E1
4.02E-1
1.26E-2
3.09E1
2.01E1
Cd foil
covers
1.22E0
3.78E-1
1.85E-1
1.23E-1
9.73E-2
Total
1.67E7
6.65E2
2.69E2
2.16E2
1.78E2
Total
5.99E6
9.72E2
8.80E1
7.10E1
5.90E1
The following table shows the activity for just the samples after the 2 x 6 tube sample
holder and cadmium foils have been removed.
Time
0 hrs
1 hrs
2 hrs
3 hrs
4 hrs
Gold
wires
1.02E0
1.64E-3
1.27E-3
1.01E-3
8.14E-4
Quartz
7.23E0
3.65E-1
2.80E-1
2.15E-1
1.65E-1
Activity (mCi)
Plastic
Air
Clay SRM
1.78E+01 8.96E-3
3.44E-02
6.13E-3
2.70E-02
4.20E-3
2.24E-02
2.88E-3
1.88E-02
1.97E-3
Total
2.61E1
4.07E-1
3.12E-1
2.41E-1
1.87E-1
74
The following tables show the exposure rates for just the samples after the 2 x 6 tube
sample holder has been removed.
Time
0 hrs
1 hrs
2 hrs
3 hrs
4 hrs
Gold
wires
3.28E2
2.00E-2
1.07E-2
8.46E-3
6.78E-3
Exposure (mrem/hr) 30 cm
Quartz
Plastic
Air
Clay SRM
2.27E3
5.70E3
5.93E-2
7.62E1
3.36E0
3.91E-2
5.85E1
2.64E0
2.68E-2
4.49E1
2.17E0
1.83E-2
3.44E1
1.81E0
1.26E-2
Gold
wires
7.19E1
6.07E-3
3.66E-3
2.87E-3
2.28E-3
Exposure (mrem/hr) 50 cm
Quartz
Plastic
Air
Clay SRM
4.98E2
1.25E3
5.93E-2
1.65E1
7.45E-1
3.91E-2
1.26E1
5.86E-1
2.68E-2
9.69E0
4.83E-1
1.83E-2
7.44E0
4.02E-1
1.26E-2
Time
0 hrs
1 hrs
2 hrs
3 hrs
4 hrs
Total
8.30E3
7.96E1
6.12E1
4.71E1
3.62E1
Total
1.82E3
1.73E1
1.32E1
1.02E1
7.86E0
The following are graphs of the exposure rate for each of the materials that will be
irradiated.
Gold Wires
Exposure rate at 30 cm
75
Sample Holder Al 1100
Exposure rate at 30 cm
An enlargement of the previous graph
Sample Holder Al 6061
Exposure rate at 30 cm
76
Exposure rate at 50 cm
Pottery Samples
Exposure rate at 30 cm
Plastic Clay SRM
Exposure rate at 30 cm
77
Quartz Ampoules
Exposure rate at 30 cm
Plastic Clay Long Irradiation
Neutron Activation Activity Prediction Authorization
November 7, 2012
Chad Durrant
Objective: The purpose of this test is to confirm that the plastic clay standard reference
material (SRM) will be a sufficient comparative material for future irradiations with
unknown pottery samples. This will also serve as a good practice run for the reactor
operators and for handling and counting the material.
Proposal: ~1 g total weight of plastic clay SRM samples are sealed in 6-10 quartz
ampoules and wrapped in aluminum foils. 0.015 g of AuAl wires are sealed in 6 quartz
ampoules; three of these are wrapped in cadmium foils (total cadmium weight
conservatively ~3 g). There will also be two empty sealed quartz ampoules. The total
weight of the quartz ampoules will be approximately 20 g. All the quartz ampoules will
be placed in the 2 x 6 tube sample holder and irradiated in the 2 x 6 tube located on the
reactor core face. The 2 x 6 tube sample holder is approximately 100 g of Al 6061 (lower
purity Al) and 160 g of Al 1100 (high purity Al). The sample will be irradiated for 8
hours at about 900 kW with the safety control rod at the upper limit position. This will
give an approximate total thermal fluence of about 1.55 x 1013, total fast fluence of about
4.0 x 1012, and a resonance fluence of about 8 x 1011.
Activity Predictions: The following is a table with the prediction for the total amount of
activity for the samples and the holder for up to 8 days after the irradiation.
78
Time
0 day
1 day
2 day
3 day
4 day
5 day
6 day
7 day
8 day
Gold
wires
3.51E1
2.68E-1
1.95E-1
1.48E-1
1.14E-1
8.77E-2
6.78E-2
5.24E-2
4.06E-2
Quartz
3.90E2
4.53E-1
8.53E-4
2.07E-5
6.31E-6
2.24E-6
1.03E-6
6.08E-7
4.48E-7
Plastic
Clay SRM
3.47E2
2.98E0
8.30E-1
2.53E-1
9.13E-2
4.44E-2
3.01E-2
2.53E-2
2.34E-2
Activity (mCi)
Air
Holder
Al 1100
2.09E0
3.54E5
2.35E-4
4.15E2
0
1.12E2
0
3.10E1
0
8.76E0
0
2.64E0
0 9.43E-1
0 4.72E-1
0 3.39E-1
Holder
Al 6061
2.15E5
3.37E2
1.31E2
6.88E1
4.59E1
3.50E1
2.85E1
2.39E1
2.05E1
Cd foil
covers
4.01E2
1.03E2
7.37E1
5.43E1
4.03E1
3.00E1
2.24E1
1.69E1
1.28E1
Total
5.70E5
8.59E2
3.18E2
1.55E2
9.52E1
6.78E1
5.19E1
4.13E1
3.37E1
The predicted exposure rates that would be produced by these same materials are
calculated for distances 30 cm and 50 cm away from the irradiated materials and shown
respectively in the tables below.
Time
0 day
1 day
2 day
3 day
4 day
5 day
6 day
7 day
8 day
Gold
wires
1.06E4
1.43E0
7.06E-1
4.20E-1
2.83E-1
2.06E-1
1.55E-1
1.18E-1
9.08E-2
Quartz
9.59E4
9.44E1
1.77E-1
4.30E-3
1.32E-3
4.34E-4
1.43E-4
4.72E-5
3.07E-7
Exposure (mrem/hr) 30 cm
Plastic
Air
Holder Holder
Clay SRM
Al 1100 Al 6061
1.05E5
1.33E1
1.12E8
6.80E7
2.93E2 1.50E-3
9.39E3
6.02E3
9.66E1
0
3.04E3
2.03E3
3.30E1
0
9.92E2
7.31E2
1.21E1
0
3.25E2
2.95E2
5.14E0
0
1.07E2
1.43E2
2.81E0
0
3.62E1
8.62E1
1.99E0
0
1.29E1
6.18E1
1.68E0
0
5.28E0
4.93E1
Cd foil
covers
1.20E3
2.54E2
1.81E2
1.33E2
9.79E1
7.22E1
5.34E1
3.96E1
2.95E1
Total
1.80E8
1.61E4
5.35E3
1.89E3
7.30E2
3.28E2
1.79E2
1.16E2
8.59E1
The predicted exposure calculated at 50 cm.
Time
0 day
1 day
2 day
3 day
4 day
5 day
6 day
7 day
8 day
Gold
wires
2.34E3
4.02E-1
2.17E-1
1.39E-1
9.80E-2
7.27E-2
5.52E-2
4.24E-2
3.26E-2
Quartz
2.09E4
2.04E1
3.84E-2
9.63E-4
2.96E-4
9.75E-5
3.21E-5
1.06E-5
1.10E-7
Exposure (mrem/hr) 50 cm
Plastic
Air
Holder Holder
Clay SRM
Al 1100 Al 6061
2.31E4
4.79E0
2.46E7
1.49E7
6.60E1
5.40E4
2.18E3
1.42E3
2.17E1
0
7.00E2
4.87E2
7.42E0
0
2.28E2
1.83E2
2.71E0
0
7.45E1
7.97E1
1.16E0
0
2.47E1
4.28E1
6.33E-1
0
8.44E0
2.82E1
4.50E-1
0
3.14E0
2.13E1
3.80E-1
0
1.40E0
1.75E1
Cd foil
covers
4.31E2
9.14E1
6.53E1
4.79E1
3.53E1
2.60E1
1.92E1
1.43E1
1.06E1
Total
3.95E7
5.78E4
1.27E3
4.66E2
1.92E2
9.47E1
5.65E1
3.92E1
2.99E1
79
It is anticipated that after irradiation the sample holder will remain in the 2 x 6 tube in the
reactor pool for 136 hours or just over 5 ½ days before extracting it to transfer the
samples. This will allow many of the short lived radioactive byproducts to decay away
thereby significantly decreasing the activity of the material to be handled thus minimizing
the exposure to the individual. The sample holder with samples will be extracted from the
2 x 6 tube after 5 ½ days into a shielded area and then transported to a work area in the
reactor bay. There the individual samples will be taken out one at a time and placed into
a plastic holder that will be used to transfer the samples for counting. The activity and
exposure rate for just the samples after the 2 x 6 tube sample holder and cadmium foil
covers have been removed are shown below in the following two tables.
Time
Gold
wires
Quartz
Activity (mCi)
Plastic
Clay SRM
Air
Total
3.47E2
2.09E0
7.74E2
3.70E0
1.03E0
4.01E-1
2.05E-1
1.32E-1
9.79E-2
7.77E-2
6.40E-2
0 day
3.51E1
3.90E2
1 day
2.68E-1
4.53E-1
2.98E0
2.35E-4
2 day
1.95E-1
8.53E-4
8.30E-1
0
3 day
1.48E-1
2.07E-5
2.53E-1
0
4 day
1.14E-1
6.31E-6
9.13E-2
0
5 day
8.77E-2
2.24E-6
4.44E-2
0
6 day
6.78E-2
1.03E-6
3.01E-2
0
7 day
5.24E-2
6.08E-7
2.53E-2
0
8 day
4.06E-2
4.48E-7
2.34E-2
0
Time
Gold
wires
Exposure (mrem/hr) 30 cm
Quartz
Plastic
Air
Clay SRM
Total
0 day
1.06E4
9.59E4
1.05E5
1.33E1
1 day
1.43E0
9.44E1
2.93E2
1.50E-3
2 day
7.06E-1
1.77E-1
9.66E1
0
3 day
4.20E-1
4.30E-3
3.30E1
0
4 day
2.83E-1
1.32E-3
1.21E1
0
5 day
2.06E-1
4.34E-4
5.14E0
0
6 day
1.55E-1
1.43E-4
2.81E0
0
7 day
1.18E-1
4.72E-5
1.99E0
0
8 day
9.08E-2
3.07E-7
1.68E0
0
2.12E5
3.89E2
9.75E1
3.34E1
1.24E1
5.35E0
2.97E0
2.11E0
1.77E0
80
Below are the expected exposure charts for the different elements/materials that will be
present in the sample holder.
Gold wire predicted exposure rate at 30 cm
Quartz ampoule predicted exposure rate at 30 cm
Plastic Clay SRM predicted exposure at 30 cm
81
Sample Holder Al 1100 predicted exposure rate at 30 cm
Sample Holder Al 6061 predicted exposure rate at 30 cm
Cadmium Foil Covers predicted exposure rate at 30 cm
82
Pottery Short Irradiation
Neutron Activation Activity Prediction Authorization
November 6, 2012
Chad Durrant
Objective: The purpose of this test is to irradiate 15 pottery samples of unknown
composition with some standard reference materials (SRMs) and gold wires. The
standard reference material will be used in comparative neutron activation analysis
method and the gold wires will be used in the flux calculation and k0 method in order to
determine the composition of the unknown pottery samples. This is a short irradiation
that will help determine shorter-lived isotopes, while a second longer irradiation will
determine longer lived isotopes.
Proposal: ~1.5 g total weight of unknown pottery samples are sealed in 15 quartz
ampoules and wrapped in aluminum foils. 0.015 g of AuAl wires are sealed in 6 quartz
ampoules; three of these are wrapped in cadmium foils (total cadmium weight ~3 g).
There will also be two samples of plastic clay SRM sealed in quartz ampoules. The total
weight of the quartz ampoules will be approximately 31.25 g. All of the quartz ampoules
will be placed in the 2 x 6 sample holder and irradiated in the 2 x 6 tube located on the
reactor core face. The sample holder is approximately 100 g of Al 6061 (lower purity Al)
and 160 g of Al 1100 (high purity Al). The sample will be irradiated for 6 minutes at
about 110 kW with the safety control rod at the upper limit position. This will give an
approximate total thermal fluence of about 1.7 x 1012, total fast fluence of about 4.4 x
1011, and a resonance fluence of about 8.8 x 1010.
Activity Predictions: The following is a table with the prediction for the total amount of
activity for the samples the and 2 x 6 tube sample holder for up to four hours after
irradiation.
Time
0 hrs
1 hrs
2 hrs
3 hrs
4 hrs
Gold
wires
3.06E0
4.91E-3
3.82E-3
3.04E-3
2.44E-3
Quartz
2.01E1
1.02E0
7.79E-1
5.98E-1
4.59E-1
Pottery
Samples
5.01E1
9.18E-2
7.10E-2
5.80E-2
4.82E-2
Activity (mCi)
Plastic
Air
Clay SRM
5.95E0
8.96E-3
1.15E-2
6.13E-3
9.01E-3
4.20E-3
7.46E-3
2.88E-3
6.27E-3
1.97E-3
Holder
Al 1100
3.22E4
1.45E1
1.10E1
8.80E0
7.12E0
Holder
Al 6061
1.96E4
9.29E0
7.04E0
5.67E0
4.61E0
Cd foil
covers
2.38E0
1.06E0
6.02E-1
4.12E-1
3.25E-1
Total
5.19E4
2.60E1
1.95E1
1.56E1
1.26E1
The predicted exposure values are calculated respectively for distances 30 cm and 50 cm
away from the irradiated materials. The following two tables show the total exposure
rates for the samples at 30 and 50 cm respectively. It is anticipated that the sample holder
will be pulled from the 2 x 6 tube after 2 hours and transferred to a shielded work area in
the reactor bay. In the work area the quartz ampoules will be taken out of the aluminum
83
sample holder and placed into a plastic holder that will be used to transfer the samples for
counting.
Time
0 hrs
1 hrs
2 hrs
3 hrs
4 hrs
Gold
wires
9.83E2
6.00E-2
3.22E-2
2.54E-2
2.03E-2
Quartz
Gold
wires
3.54E2
2.16E-2
1.16E-2
9.14E-3
7.33E-3
Quartz
6.30E3
2.12E2
1.62E2
1.25E2
9.57E1
Pottery
Samples
1.58E4
1.01E1
8.16E0
6.89E0
5.89E0
Exposure (mrem/hr) 30 cm
Plastic
Air
Holder
Clay SRM
Al 1100
1.90E3
5.93E-2
1.04E7
1.12E0
3.91E-2
3.54E2
8.78E-1
2.68E-2
1.25E2
7.23E-1
1.83E-2
1.02E2
6.02E-1
1.26E-2
8.58E1
Holder
Al 6061
6.29E6
2.30E2
8.20E1
6.67E1
5.59E1
Cd foil
covers
1.02E1
3.15E0
1.54E0
1.03E0
8.11E-1
Pottery
Samples
3.48E3
2.23E0
1.80E0
1.52E0
1.31E0
Exposure (mrem/hr) 50 cm
Plastic
Air
Holder
Clay SRM
Al 1100
4.17E2
5.93E-2
3.73E6
2.48E-1
3.91E-2
1.27E2
1.95E-1
2.68E-2
4.51E1
1.61E-1
1.83E-2
3.67E1
1.34E-1
1.26E-2
3.09E1
Holder
Al 6061
2.26E6
8.27E2
2.95E1
2.40E1
2.01E1
Cd foil
covers
3.66E0
1.13E0
5.54E-1
3.69E-1
2.92E-1
Time
0 hrs
1 hrs
2 hrs
3 hrs
4 hrs
2.27E3
7.62E1
5.85E1
4.49E1
3.44E1
Total
1.67E7
8.10E2
3.80E2
3.02E2
2.45E2
Total
6.00E6
1.03E3
1.36E2
1.08E2
8.72E1
The following tables show the exposure rates for just the samples after the 2 x 6 tube
sample holder has been removed.
Time
0 hrs
1 hrs
2 hrs
3 hrs
4 hrs
Gold
wires
9.83E2
6.00E-2
3.22E-2
2.54E-2
2.03E-2
Quartz
Gold
wires
3.54E2
2.16E-2
1.16E-2
9.14E-3
7.33E-3
Quartz
6.30E3
2.12E2
1.62E2
1.25E2
9.57E1
Time
0 hrs
1 hrs
2 hrs
3 hrs
4 hrs
2.27E3
7.62E1
5.85E1
4.49E1
3.44E1
Exposure (mrem/hr) 30 cm
Pottery
Plastic
Samples Clay SRM
1.58E4
1.90E3
1.01E1
1.12E0
8.16E0
8.78E-1
6.89E0
7.23E-1
5.89E0
6.02E-1
Exposure (mrem/hr) 50 cm
Pottery
Plastic
Samples Clay SRM
3.48E3
4.17E2
2.23E0
2.48E-1
1.80E0
1.95E-1
1.52E0
1.61E-1
1.31E0
1.34E-1
Air
Total
5.93E-2
3.91E-2
2.68E-2
1.83E-2
1.26E-2
2.50E4
2.23E2
1.71E2
1.33E2
1.02E2
Air
Total
5.93E-2
3.91E-2
2.68E-2
1.83E-2
1.26E-2
6.52E3
7.87E1
6.05E1
4.66E1
3.59E1
The following are graphs of the exposure rate for each of the materials that will be
irradiated.
84
Gold Wires
Exposure rate at 30 cm
Sample Holder Al 1100
Exposure rate at 30 cm
An enlargement of the previous graph
85
Sample Holder Al 6061
Exposure rate at 30 cm
An enlargement of the previous graph
Pottery Samples
Exposure rate at 30 cm
86
Plastic Clay SRM
Exposure rate at 30 cm
Quartz Ampoules
Exposure rate at 30 cm
An enlargement of the previous graph
87
Cadmium Foils
Exposure rate at 30 cm
Pottery Long Irradiation
Neutron Activation Activity Prediction Authorization
November 6, 2012
Chad Durrant
Objective: The purpose of this test is to irradiate 15 pottery samples of unknown
composition with some standard reference materials (SRMs) and gold wires. The
standard reference material will be used in comparative neutron activation analysis
method and the gold wires will be used in the flux calculation k0 method in order to
determine the composition of the unknown pottery. This is a long irradiation that will be
performed after the similar short irradiation and will be used to determine longer-lived
isotopes.
Proposal: ~1.5 g total weight of unknown pottery samples are sealed in 15 quartz
ampoules and wrapped in aluminum foils. 0.015 g of AuAl wires are sealed in 6 quartz
ampoules; three of these are wrapped in cadmium foils (total cadmium weight
conservatively ~3 g). There will also be two samples of plastic clay SRM also sealed in
quartz ampoules. The total weight of the quartz ampoules will be approximately 31.25 g.
All the quartz ampoules will be placed in the 2 x 6 tube sample holder and irradiated in
the 2 x 6 tube located on the reactor core face. The 2 x 6 tube sample holder is
approximately 100 g of Al 6061 (lower purity Al) and 160 g of Al 1100 (high purity Al).
The sample will be irradiated for 8 hours at about 900 kW with the safety control rod at
the upper limit position. This will give an approximate total thermal fluence of about
1.55 x 1013, total fast fluence of about 4.0 x 1012, and a resonance fluence of about 8 x
1011.
88
Activity Predictions: The following is a table with the prediction for the total amount of
activity for the samples and the holder for up to 8 days after the irradiation.
Time
0 day
1 day
2 day
3 day
4 day
5 day
6 day
7 day
8 day
Gold
wires
3.51E1
2.68E-1
1.95E-1
1.48E-1
1.14E-1
8.77E-2
6.78E-2
5.24E-2
4.06E-2
Quartz
6.09E2
7.08E-1
1.33E-3
3.23E-5
9.87E-6
3.50E-6
1.60E-6
9.51E-7
6.99E-7
Pottery
Samples
5.81E2
4.67E0
1.48E0
5.40E-1
2.35E-1
1.25E-1
7.98E-2
5.81E-2
4.61E-2
Activity (mCi)
Plastic
Air
Clay SRM
6.95E1
2.09E0
5.96E-1 2.35E-4
1.66E-1
0
5.06E-2
0
1.83E-2
0
8.88E-3
0
6.02E-3
0
5.06E-3
0
4.68E-3
0
Holder
Al 1100
3.54E5
4.15E2
1.12E2
3.10E1
8.76E0
2.64E0
9.43E-1
4.72E-1
3.39E-1
Holder
Al 6061
2.15E5
3.37E2
1.31E2
6.88E1
4.59E1
3.50E1
2.85E1
2.39E1
2.05E1
Cd foil
covers
4.01E2
1.03E2
7.37E1
5.43E1
4.03E1
3.00E1
2.24E1
1.69E1
1.28E1
Total
5.71E5
8.61E2
3.19E2
1.55E2
9.53E1
6.79E1
5.20E1
4.14E1
3.37E1
The predicted exposure rates that would be produced by these same materials are
calculated for distances 30 cm and 50 cm away from the irradiated materials and shown
respectively in the tables below.
Time
0 day
1 day
2 day
3 day
4 day
5 day
6 day
7 day
8 day
Gold
wires
1.06E4
1.43E0
7.06E-1
4.20E-1
2.83E-1
2.06E-1
1.55E-1
1.18E-1
9.08E-2
Quartz
1.50E5
1.48E2
2.77E-1
6.72E-3
2.06E-3
6.79E-4
2.23E-4
7.38E-5
4.79E-7
Pottery
Samples
1.76E5
7.48E2
2.45E2
8.09E1
2.69E1
9.08E0
3.18E0
1.21E0
5.40E-1
Exposure (mrem/hr) 30 cm
Plastic
Air
Holder
Clay SRM
Al 1100
2.10E4
1.33E1
1.12E8
5.86E1 1.50E-3
9.39E3
1.93E1
0
3.04E3
6.60E0
0
9.92E2
2.41E0
0
3.25E2
1.03E0
0
1.07E2
5.62E-1
0
3.62E1
3.99E-1
0
1.29E1
3.36E-1
0
5.28E0
Holder
Al 6061
6.80E7
6.02E3
2.03E3
7.31E2
2.95E2
1.43E2
8.62E1
6.18E1
4.93E1
Cd foil
covers
1.20E3
2.54E2
1.81E2
1.33E2
9.79E1
7.22E1
5.34E1
3.96E1
2.95E1
Holder
Al 6061
1.49E7
1.42E3
4.87E2
1.83E2
7.97E1
4.28E1
2.82E1
2.13E1
1.75E1
Cd foil
covers
4.31E2
9.14E1
6.53E1
4.79E1
3.53E1
2.60E1
1.92E1
1.43E1
1.06E1
Total
1.80E8
1.66E4
5.52E3
1.94E3
7.47E2
3.33E2
1.80E2
1.16E2
8.50E1
The predicted exposure calculated at 50 cm.
Time
0 day
1 day
2 day
3 day
4 day
5 day
6 day
7 day
8 day
Gold
wires
2.34E3
4.02E-1
2.17E-1
1.39E-1
9.80E-2
7.27E-2
5.52E-2
4.24E-2
3.26E-2
Quartz
3.26E4
3.19E1
6.00E-2
1.51E-3
4.63E-4
1.52E-4
5.02E-5
1.66E-5
1.73E-7
Pottery
Samples
3.86E4
1.68E2
5.51E1
1.83E1
6.11E0
2.09E0
7.58E-1
3.08E-1
1.53E-1
Exposure (mrem/hr) 50 cm
Plastic
Air
Holder
Clay SRM
Al 1100
4.61E3
4.79E0
2.46E7
1.32E1
5.40E4
2.18E3
4.35E0
0
7.00E2
1.48E0
0
2.28E2
5.43E-1
0
7.45E1
2.31E-1
0
2.47E1
1.27E-1
0
8.44E0
9.01E-2
0
3.14E0
7.60E-2
0
1.40E0
Total
3.96E7
3.90E3
1.31E3
4.79E2
1.96E2
9.59E1
5.68E1
3.92E1
2.98E1
89
It is anticipated that after irradiation the sample holder will remain in the 2 x 6 tube in the
reactor pool for 192 hours or 8 days before extracting it to transfer the samples. This will
allow many of the short lived radioactive byproducts to decay away thereby significantly
decreasing the activity of the material to be handled thus minimizing the exposure to the
individual. The sample holder with samples will be extracted from the 2 x 6 tube after 8
days into a shielded area and then transported to a work area in the reactor bay. There the
individual samples will be taken out one at a time and placed into a plastic holder that
will be used to transfer the samples for counting. The activity and exposure rate for just
the samples after the 2 x 6 tube sample holder and cadmium foil covers have been
removed are shown below in the following two tables.
Time
0 day
1 day
2 day
3 day
4 day
5 day
6 day
7 day
8 day
Gold
wires
3.51E1
2.68E-1
1.95E-1
1.48E-1
1.14E-1
8.77E-2
6.78E-2
5.24E-2
4.06E-2
Quartz
6.09E2
7.08E-1
1.33E-3
3.23E-5
9.87E-6
3.50E-6
1.60E-6
9.51E-7
6.99E-7
Time
0 day
1 day
2 day
3 day
4 day
5 day
6 day
7 day
8 day
Gold
wires
1.06E4
1.43E0
7.06E-1
4.20E-1
2.83E-1
2.06E-1
1.55E-1
1.18E-1
9.08E-2
Quartz
1.50E5
1.48E2
2.77E-1
6.72E-3
2.06E-3
6.79E-4
2.23E-4
7.38E-5
4.79E-7
Activity (mCi)
Pottery
Plastic
Samples Clay SRM
5.81E2
6.95E1
4.67E0
5.96E-1
1.48E0
1.66E-1
5.40E-1
5.06E-2
2.35E-1
1.83E-2
1.25E-1
8.88E-3
7.98E-2
6.02E-3
5.81E-2
5.06E-3
4.61E-2
4.68E-3
Air
Total
2.09E0
2.35E-4
0
0
0
0
0
0
0
1.30E3
6.24E0
1.84E0
7.39E-1
3.67E-1
2.22E-1
1.54E-1
1.16E-1
9.14E-2
Exposure (mrem/hr) 30 cm
Pottery
Plastic
Air
Samples Clay SRM
1.76E5
2.10E4
1.33E1
7.48E2
5.86E1 1.50E-3
2.45E2
1.93E1
0
8.09E1
6.60E0
0
2.69E1
2.41E0
0
9.08E0
1.03E0
0
3.18E0
5.62E-1
0
1.21E0
3.99E-1
0
5.40E-1
3.36E-1
0
Total
3.58E5
9.56E2
2.65E2
8.79E1
2.96E1
1.03E1
3.90E0
1.73E0
9.67E-1
Below are the expected exposure charts for the different elements/materials that will be
present in the sample holder.
90
Gold wire predicted exposure rate at 30 cm
Quartz ampoule predicted exposure rate at 30 cm
Pottery Sample predicted exposure rate at 30 cm
91
Plastic Clay SRM predicted exposure at 30 cm
Sample Holder Al 1100 predicted exposure rate at 30 cm
Sample Holder Al 6061 predicted exposure rate at 30 cm
92
Cadmium Foil Covers predicted exposure rate at 30 cm
93
Appendix D
Comprehensive Sample Data
The trace element composition for each of the Italian tile samples are given in Tables D.1
through D.15.
Table D.1. Experimentally determined composition of Sample 139B using the plastic clay
comparator standard.
Sample 139B
Element
Sodium
Potassium
Manganese
Strontium
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Weight Percent and respective error
Nuclide
> 2 hours
Error ±
Na-24
6.99E-03
8.54E-04
K-42
3.09E-02
4.07E-03
Mn-56
1.14E-03
1.32E-04
Sr-87m
6.20E-04
1.13E-04
Eu-152m
1.88E-06
2.25E-07
Eu-154
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Hf-181
Ca-47
Zr-95
Id Confidence
0.992
0.987
0.979
0.987
0.998
8 days
1.99E-05
Error ±
2.60E-06
Id Confidence
0.986
2.02E-07
2.42E-08
0.983
1.25E-04
1.56E-05
0.978
6.43E-09
1.43E-09
0.999
23 days
Error ±
Id Confidence
2.61E-06
3.10E-06
1.29E-05
9.31E-05
3.66E-02
1.12E-04
1.11E-04
2.58E-06
3.34E-07
3.86E-07
1.51E-06
1.38E-05
4.24E-03
1.44E-05
1.48E-05
3.24E-07
0.416
0.865
0.98
1
0.976
0.978
0.966
0.991
9.91E-04
4.74E-06
1.20E-04
5.70E-07
0.957
0.988
2.67E-04
4.79E-05
0.996
Table D.2. Experimentally determined composition of Sample 140B using the plastic clay
comparator standard.
Sample 140B
Element
Sodium
Potassium
Manganese
Strontium
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Ba-135m
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
6.46E-03
7.89E-04
0.991
2.82E-02
3.72E-03
0.986
1.19E-03
1.38E-04
0.976
4.49E-04
9.79E-05
0.985
1.90E-06
2.26E-07
0.997
8 days
8.95E-04
2.13E-02
Error ±
1.09E-04
3.75E-03
Id Confidence
0.988
0.984
23 days
Error ±
Id Confidence
8.25E-07
1.21E-06
1.36E-05
5.79E-05
3.95E-03
4.99E-05
9.61E-05
7.55E-07
1.12E-07
1.95E-07
1.59E-06
8.69E-06
4.87E-04
6.51E-06
1.27E-05
9.32E-08
0.42
0.693
0.989
1
0.986
0.987
0.979
0.924
3.21E-06
3.19E-06
1.21E-05
1.08E-04
5.64E-02
1.42E-04
1.57E-04
2.55E-06
4.09E-07
4.06E-07
1.41E-06
1.60E-05
6.53E-03
1.81E-05
2.03E-05
3.19E-07
0.419
0.768
0.985
1
0.981
0.981
0.972
0.992
4.98E-04
4.16E-04
4.78E-06
4.07E-04
6.02E-05
1.68E-04
5.77E-07
5.30E-05
0.962
0.895
0.988
0.989
9.07E-04
1.10E-04
0.958
4.38E-06
5.27E-07
0.988
2.89E-04
4.98E-05
0.996
94
Table D.3. Experimentally determined composition of Sample 141B using the plastic clay
comparator standard.
Sample 141B
Element
Sodium
Potassium
Manganese
Strontium
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Hf-181
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
9.71E-03
1.17E-03
0.962
4.07E-02
5.28E-03
0.941
1.05E-03
1.20E-04
0.949
6.65E-04
1.51E-04
0.978
2.04E-06
2.42E-07
0.981
8 days
2.44E-04
1.82E-02
Error ±
2.99E-05
5.21E-03
Id Confidence
0.989
0.947
23 days
Error ±
Id Confidence
6.18E-07
8.71E-08
0.423
3.00E-05
8.62E-05
1.45E-02
5.91E-05
1.60E-04
2.15E-07
3.44E-06
1.28E-05
1.65E-03
7.81E-06
2.09E-05
2.79E-08
0.989
1.000
0.986
0.986
0.979
1
9.40E-06
3.56E-06
1.12E-05
7.92E-05
3.72E-02
1.70E-04
2.11E-04
5.72E-06
1.19E-06
4.71E-07
1.28E-06
1.17E-05
4.49E-03
2.15E-05
2.70E-05
7.01E-07
0.417
0.767
0.987
1
0.984
0.983
0.977
0.985
3.76E-04
5.15E-05
0.957
1.02E-03
5.59E-06
2.72E-04
1.23E-04
6.62E-07
5.50E-05
0.959
0.988
0.995
Table D.4. Experimentally determined composition of Sample 142B using the plastic clay
comparator standard.
Sample 142B
Element
Sodium
Potassium
Manganese
Strontium
Europium*
Scandium*
Titanium
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Sc-48
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Ba-135m
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
1.34E-02
1.61E-03
0.972
2.46E-02
3.21E-03
0.963
1.03E-03
1.18E-04
0.954
7.14E-04
1.44E-04
0.977
1.89E-06
2.25E-07
0.991
8 days
6.82E-04
3.90E-02
Error ±
8.19E-05
8.21E-03
Id Confidence
0.989
0.978
23 days
Error ±
Id Confidence
7.37E-07
1.07E-06
8.97E-06
1.07E-07
3.03E-07
1.03E-06
0.421
0.373
0.989
5.27E-05
7.06E-03
7.36E-05
9.69E-05
8.31E-07
7.77E-06
8.60E-04
9.53E-06
1.27E-05
1.01E-07
1
0.986
0.986
0.978
1
3.63E-06
5.35E-06
1.40E-05
6.74E-03
8.49E-05
4.23E-02
1.24E-04
2.39E-04
3.11E-06
4.56E-07
6.50E-07
1.61E-06
1.46E-03
1.25E-05
4.81E-03
1.56E-05
3.01E-05
3.81E-07
0.417
0.873
0.988
0.964
1.000
0.985
0.986
0.978
0.985
5.24E-04
3.88E-04
3.97E-06
1.71E-04
6.37E-05
8.23E-05
4.80E-07
2.33E-05
0.962
0.9
0.895
0.841
9.46E-04
1.15E-04
0.959
4.83E-06
5.71E-07
0.988
3.11E-04
6.73E-05
0.993
Table D.5. Experimentally determined composition of Sample 143B using the plastic clay
comparator standard.
Sample 143B
Element
Sodium
Potassium
Manganese
Strontium
Europium*
Scandium*
Titanium
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Sc-48
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Ba-135m
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
8.23E-03
1.03E-03
0.962
3.34E-02
4.47E-03
0.943
1.04E-03
1.24E-04
0.940
7.60E-04
1.37E-04
0.971
2.19E-06
2.65E-07
0.985
8 days
8.05E-05
1.42E-02
Error ±
1.03E-05
5.63E-03
Id Confidence
0.99
0.981
1.12E-06
1.82E-05
2.34E-07
2.17E-06
0.478
0.989
5.03E-05
1.75E-02
5.20E-05
7.85E-05
2.34E-07
7.96E-06
2.07E-03
7.09E-06
1.05E-05
3.17E-08
1.000
0.986
0.985
0.977
1
2.22E-04
4.48E-04
3.18E-06
3.25E-05
1.97E-04
3.95E-07
0.962
0.902
0.987
23 days
Error ±
Id Confidence
9.37E-06
5.27E-06
1.20E-05
1.07E-02
8.02E-05
3.88E-02
1.20E-04
2.08E-04
2.71E-06
1.21E-06
6.54E-07
1.43E-06
2.38E-03
1.21E-05
4.59E-03
1.56E-05
2.73E-05
3.47E-07
0.411
0.971
0.987
0.953
1
0.983
0.984
0.975
0.987
1.16E-03
1.45E-04
0.958
5.43E-06
6.67E-07
0.988
3.13E-04
6.09E-05
0.995
95
Table D.6. Experimentally determined composition of Sample 144B using the plastic clay
comparator standard.
Sample 144B
Element
Sodium
Potassium
Manganese
Strontium
Europium*
Scandium*
Titanium
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Sc-48
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Ba-135m
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
8.36E-03
1.04E-03
0.961
3.09E-02
4.14E-03
0.944
9.30E-04
1.10E-04
0.937
8.30E-04
1.57E-04
0.968
2.07E-06
2.52E-07
0.984
8 days
1.40E-03
2.83E-02
Error ±
1.74E-04
7.67E-03
Id Confidence
0.991
0.958
9.51E-07
1.27E-06
1.82E-05
1.29E-07
2.68E-07
2.17E-06
0.423
0.636
0.99
8.03E-05
7.26E-03
6.24E-05
1.41E-04
9.34E-07
1.21E-05
9.14E-04
8.33E-06
1.89E-05
1.18E-07
1
0.988
0.988
0.98
1
8.50E-04
1.07E-03
5.14E-06
5.55E-04
1.81E-04
1.05E-04
3.02E-04
6.36E-07
7.43E-05
3.15E-05
0.962
0.896
0.987
0.991
0.994
23 days
Error ±
Id Confidence
3.32E-06
3.83E-06
1.37E-05
8.87E-03
1.15E-04
4.99E-02
2.12E-04
1.74E-04
3.21E-06
4.32E-07
5.14E-07
1.64E-06
2.00E-03
1.73E-05
5.92E-03
2.76E-05
2.32E-05
4.08E-07
0.41
0.77
0.987
0.397
1
0.983
0.984
0.975
0.985
9.02E-04
1.15E-04
0.958
6.25E-06
7.67E-07
0.988
3.21E-04
5.73E-05
0.993
Table D.7. Experimentally determined composition of Sample 145B using the plastic clay
comparator standard.
Sample 145B
Element
Sodium
Potassium
Manganese
Strontium
Europium*
Scandium*
Titanium
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Sc-48
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Ba-135m
Hf-181
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
8.69E-03
1.05E-03
0.951
2.67E-02
3.49E-03
0.939
1.10E-03
1.27E-04
0.923
1.04E-03
2.41E-04
0.957
1.88E-06
2.25E-07
0.98
8 days
2.49E-04
Error ±
3.10E-05
Id Confidence
0.989
23 days
Error ±
Id Confidence
5.44E-07
7.68E-08
0.427
3.36E-05
3.88E-06
0.989
1.02E-04
2.26E-02
6.16E-05
1.52E-04
3.01E-07
1.52E-05
2.59E-03
8.12E-06
1.98E-05
3.91E-08
1
0.987
0.986
0.979
0.999
7.72E-05
4.15E-05
1.36E-04
7.19E-02
1.02E-03
3.91E-01
1.20E-03
1.71E-03
2.73E-05
9.89E-06
5.53E-06
1.57E-05
2.76E-02
1.50E-04
4.47E-02
1.53E-04
2.20E-04
3.43E-06
0.399
0.685
0.98
0.987
1
0.976
0.977
0.963
0.99
3.92E-04
1.21E-03
4.59E-06
5.51E-05
3.29E-04
5.57E-07
0.96
0.907
0.988
8.46E-03
1.05E-03
0.959
5.14E-05
3.03E-03
6.14E-06
5.50E-04
0.988
0.995
96
Table D.8. Experimentally determined composition of Sample 146B using the plastic clay
comparator standard.
Sample 146B
Element
Sodium
Potassium
Manganese
Strontium
Europium*
Scandium*
Calcium
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Ca-47
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Ba-135m
Hf-181
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
8.06E-03
9.73E-04
0.951
2.06E-02
2.70E-03
0.934
1.08E-03
1.24E-04
0.919
7.30E-04
1.97E-04
0.957
1.75E-06
2.10E-07
0.974
8 days
1.57E-03
2.79E-02
Error ±
1.90E-04
1.20E-02
Id Confidence
0.988
0.933
23 days
Error ±
Id Confidence
1.38E-06
1.55E-06
1.96E-05
6.90E-04
8.44E-05
7.99E-03
5.44E-05
0.000121
1.03E-06
1.95E-07
2.91E-07
2.26E-06
8.98E-05
1.26E-05
9.18E-04
7.19E-06
1.58E-05
1.26E-07
0.421
0.551
0.989
0.988
1
0.986
0.984
0.98
1
9.64E-06
3.38E-06
1.20E-05
1.24E-06
4.38E-07
1.39E-06
0.397
0.785
0.982
1.13E-04
3.59E-02
8.51E-05
0.000143
2.78E-06
1.66E-05
4.11E-03
1.09E-05
1.86E-05
3.48E-07
1
0.978
0.976
0.966
0.987
6.35E-04
1.24E-03
5.53E-06
7.86E-05
4.62E-04
6.62E-07
0.961
0.906
0.988
1.09E-03
1.36E-04
0.959
5.91E-06
1.95E-04
7.03E-07
4.31E-05
0.988
0.993
Table D.9. Experimentally determined composition of Sample 147B using the plastic clay
comparator standard.
Sample 147B
Element
Sodium
Silicon
Potassium
Manganese
Strontium
Europium*
Scandium*
Calcium
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Zirconium*
Nuclide
Na-24
Si-31
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Ca-47
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Ba-133m
Hf-181
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
5.56E-03
6.90E-04
0.942
6.77E-01
1.49E-01
0.886
2.59E-02
3.49E-03
0.923
4.53E-04
5.37E-05
0.909
5.40E-04
1.49E-04
0.945
1.65E-06
2.11E-07
0.971
8 days
5.33E-03
Error ±
6.68E-04
Id Confidence
0.987
23 days
Error ±
Id Confidence
3.26E-06
4.43E-06
5.49E-05
1.58E-03
3.62E-04
2.49E-02
1.43E-04
4.37E-04
3.24E-06
4.63E-07
7.36E-07
6.59E-06
2.13E-04
5.49E-05
2.98E-03
2.02E-05
5.90E-05
4.13E-07
0.419
0.651
0.988
0.841
1
0.986
0.982
0.978
1
1.12E-06
3.10E-07
1.13E-05
1.54E-07
4.60E-08
1.35E-06
0.397
0.689
0.985
7.93E-05
3.12E-02
1.46E-04
1.51E-04
1.68E-06
1.21E-05
3.72E-03
1.95E-05
2.08E-05
2.31E-07
1
0.981
0.983
0.973
0.985
1.50E-03
1.89E-04
0.962
7.61E-04
1.10E-04
0.96
1.68E-05
0.000469
2.09E-06
8.92E-05
0.988
0.998
5.06E-06
6.37E-07
0.988
97
Table D.10. Experimentally determined composition of Sample 148B using the plastic clay
comparator standard.
Sample 148B
Element
Sodium
Potassium
Manganese
Strontium
Europium*
Scandium*
Calcium
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Ca-47
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Ba-133m
Hf-181
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
6.83E-03
8.73E-04
0.948
3.06E-02
4.20E-03
0.93
8.51E-04
1.04E-04
0.911
6.29E-04
1.47E-04
0.944
1.98E-06
2.50E-07
0.976
8 days
8.47E-04
Error ±
1.08E-04
Id Confidence
0.985
23 days
Error ±
Id Confidence
8.11E-07
4.00E-07
1.09E-05
3.89E-04
5.43E-05
4.90E-03
5.16E-05
1.03E-04
6.10E-07
1.24E-07
1.54E-07
1.33E-06
5.47E-05
8.43E-06
5.97E-04
7.33E-06
1.44E-05
8.04E-08
0.425
0.369
0.987
0.839
1
0.984
0.984
0.972
1
1.63E-06
1.98E-06
1.04E-05
2.18E-07
2.78E-07
1.27E-06
0.394
0.689
0.987
8.43E-05
3.41E-02
1.28E-04
1.76E-04
2.25E-06
1.29E-05
4.13E-03
1.71E-05
2.39E-05
2.97E-07
1
0.983
0.981
0.976
0.985
2.63E-04
3.64E-05
0.963
9.96E-04
1.27E-04
0.958
3.49E-06
4.50E-07
0.894
5.38E-06
4.62E-04
6.76E-07
8.71E-05
0.988
0.998
Table D.11. Experimentally determined composition of Sample 149B using the plastic clay
comparator standard.
Sample 149B
Element
Sodium
Silicon
Potassium
Manganese
Strontium
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
Si-31
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
7.30E-03
9.14E-04
0.95
5.50E-02
1.20E-03
1.07E-03
2.965E-06
7.35E-03
1.44E-04
2.62E-04
3.63E-07
8 days
1.98E-04
Error ±
2.64E-05
Id Confidence
0.988
23 days
Error ±
Id Confidence
3.02E-05
9.57E-05
2.00E-02
7.13E-05
1.28E-04
3.26E-07
3.58E-06
1.45E-05
2.36E-03
9.73E-06
1.92E-05
4.53E-08
0.987
1
0.983
0.982
0.975
1
5.97E-06
2.58E-06
9.08E-06
5.78E-05
4.84E-02
1.51E-04
3.16E-04
3.14E-06
7.74E-07
3.22E-07
1.08E-06
8.77E-06
5.68E-03
1.96E-05
4.10E-05
3.99E-07
0.384
0.872
0.986
1
0.982
0.983
0.972
0.983
2.10E-04
3.82E-06
3.21E-05
4.74E-07
0.957
0.987
1.69E-03
7.45E-06
2.04E-04
9.07E-07
0.959
0.988
5.35E-04
1.03E-04
0.996
0.929
0.901
0.941
0.976
Table D.12. Experimentally determined composition of Sample 150B using the plastic clay
comparator standard.
Sample 150B
Element
Sodium
Potassium
Manganese
Strontium
Europium*
Scandium*
Calcium
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Ca-47
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Ba-135m
Hf-181
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
3.84E-03
4.76E-04
0.944
1.97E-02
2.65E-03
0.926
1.05E-03
1.25E-04
0.894
3.71E-06
4.44E-07
0.973
8 days
1.01E-03
Error ±
1.26E-04
Id Confidence
0.986
23 days
Error ±
Id Confidence
3.31E-07
3.98E-07
7.28E-06
2.24E-04
5.71E-05
6.25E-03
6.52E-05
8.07E-05
5.59E-07
4.82E-08
8.02E-08
8.66E-07
4.31E-05
8.92E-06
7.39E-04
8.77E-06
1.05E-05
7.09E-08
0.419
0.695
0.987
0.824
1
0.983
0.983
0.977
0.999
2.16E-04
2.51E-09
1.60E-05
2.79E-05
3.20E-10
1.90E-06
0.38
0.869
0.986
6.87E-05
4.85E-02
1.75E-04
5.47E-04
8.95E-06
1.05E-05
5.73E-03
2.28E-05
7.08E-05
1.12E-06
1
0.982
0.983
0.973
0.981
2.83E-04
2.93E-04
4.18E-06
9.33E-05
3.47E-05
1.28E-04
5.12E-07
1.63E-05
0.963
0.922
0.987
0.991
1.51E-03
1.96E-04
0.959
8.04E-06
6.04E-04
9.92E-07
1.07E-04
0.988
0.994
98
Table D.13. Experimentally determined composition of Sample 151B using the plastic clay
comparator standard.
Sample 151B
Element
Sodium
Potassium
Manganese
Strontium
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Ba-135m
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
4.38E-03
5.63E-04
0.952
1.61E-02
2.23E-03
0.933
1.56E-03
1.92E-04
0.896
1.04E-03
2.79E-04
0.936
3.89E-06
4.81E-07
0.977
8 days
2.19E-04
Error ±
2.73E-05
Id Confidence
0.985
23 days
Error ±
Id Confidence
2.48E-07
2.76E-07
4.71E-06
2.79E-05
2.36E-03
3.25E-05
5.17E-05
4.84E-07
3.29E-08
4.63E-08
5.60E-07
4.39E-06
2.80E-04
4.37E-06
6.71E-06
6.09E-08
0.42
0.688
0.987
1
0.984
0.984
0.976
0.997
3.12E-04
6.87E-07
1.58E-05
6.90E-05
5.21E-02
1.25E-04
4.24E-04
5.37E-06
4.00E-05
8.33E-08
1.88E-06
1.05E-05
6.13E-03
1.63E-05
5.49E-05
6.75E-07
0.378
0.969
0.987
1
0.983
0.984
0.977
0.98
6.43E-05
1.28E-04
1.77E-06
8.48E-06
4.21E-05
2.17E-07
0.958
0.895
0.988
3.41E-03
4.11E-04
0.957
9.02E-06
1.10E-06
0.988
4.86E-05
8.64E-06
0.998
7.03E-04
1.18E-04
0.996
Table D.14. Experimentally determined composition of Sample 152B using the plastic clay
comparator standard.
Sample 152B
Element
Sodium
Potassium
Manganese
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Eu-152m
Eu-154
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
5.87E-03
7.76E-04
0.943
2.22E-02
3.18E-03
0.926
3.12E-03
3.96E-04
0.879
4.902E-06
6.29E-07
0.97
8 days
1.39E-04
Error ±
1.95E-05
Id Confidence
0.981
23 days
Error ±
Id Confidence
1.41E-07
2.24E-08
0.42
1.14E-05
7.35E-05
7.85E-03
4.26E-05
3.14E-05
1.53E-07
1.45E-06
1.17E-05
9.92E-04
6.20E-06
4.54E-06
2.28E-08
0.986
1
0.982
0.98
0.974
1
8.37E-04
4.77E-06
1.96E-05
1.18E-04
6.42E-02
2.05E-04
4.82E-04
8.18E-06
1.14E-04
6.45E-07
2.50E-06
1.87E-05
8.12E-03
2.83E-05
6.64E-05
1.1E-06
0.365
0.869
0.985
1
0.981
0.981
0.974
0.98
5.35E-05
1.54E-06
9.49E-06
2.05E-07
0.785
0.987
2.65E-03
1.04E-05
3.51E-04
1.35E-06
0.959
0.988
8.50E-04
1.67E-04
0.995
Table D.15. Experimentally determined composition of Sample 153B using the plastic clay
comparator standard.
Sample 153B
Element
Sodium
Potassium
Manganese
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
K-42
Mn-56
Eu-152m
Eu-154
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Sb-124
Ba-131
Ba-135m
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
> 2 hours
Error ±
Id Confidence
3.73E-03
4.95E-04
0.941
2.41E-02
3.42E-03
0.919
2.03E-03
2.59E-04
0.874
3.997E-06
5.16E-07
0.97
8 days
6.85E-04
Error ±
9.11E-05
Id Confidence
0.981
23 days
Error ±
Id Confidence
8.54E-07
6.19E-07
1.04E-05
7.93E-05
5.39E-03
6.82E-05
7.76E-05
8.84E-07
1.23E-07
1.12E-07
1.32E-06
1.27E-05
6.82E-04
9.65E-06
1.07E-05
1.19E-07
0.418
0.543
0.987
1
0.983
0.987
0.975
0.997
9.72E-04
3.91E-06
1.59E-05
7.30E-05
6.04E-02
2.00E-04
5.73E-04
1.23E-05
1.33E-04
5.22E-07
2.03E-06
1.17E-05
7.63E-03
2.76E-05
7.89E-05
1.65E-06
0.36
0.868
0.986
1
0.981
0.984
0.973
0.981
1.96E-04
4.22E-04
3.60E-06
2.63E-05
8.60E-05
4.81E-07
0.958
0.918
0.988
1.64E-03
2.27E-04
0.959
1.10E-05
1.43E-06
0.988
1.24E-04
2.08E-05
0.996
7.37E-04
1.41E-04
0.996
99
Table D.16. Experimentally determined composition of standard B1 using the plastic clay comparator standard.
Sample B1
Element
Sodium
Silicon
Potassium
Manganese
Strontium
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
Si-31
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Ba-131
Ba-135m
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
Id
> 2 hours
Error ±
Confidence
8 days
3.23E-04
2.89E-01
6.09E-02
0.962
2.40E-02
3.20E-03
0.976
3.78E-02
1.94E-03
2.26E-04
0.967
2.55E-03
3.04E-04
Error ±
4.00E-05
Id
Confidence
0.991
8.43E-03
0.972
3.65E-07
3.90E-06
1.57E-05
2.41E-04
9.15E-06
2.04E-05
6.97E-08
5.72E-05
2.82E-04
1.15E-06
0.407
0.989
1
0.987
0.986
0.98
1
0.961
0.9
0.988
0.993
8.77E-07
3.34E-05
1.05E-04
2.04E-03
6.93E-05
1.56E-04
5.60E-07
4.41E-04
1.56E-03
9.66E-06
23 days
Error ±
Id
Confidence
NIST
Concentrations
1.30E-03
2.43E-01
2.43E-02
1.73E-03
Sample
Concentrations
3.23E-04
2.89E-01
2.40E-02
1.94E-03
Percent
Difference
75.24
-18.73
1.33
-12.18
5.41E-06
3.12E-06
2.29E-05
1.11E-04
9.46E-02
1.17E-04
2.09E-04
1.11E-06
5.63E-04
7.35E-07
4.77E-07
2.68E-06
1.65E-05
1.10E-02
1.52E-05
2.71E-05
1.67E-07
9.30E-05
0.387
0.378
0.986
1
0.982
0.983
0.976
0.99
0.785
5.41E-06
-184.52
2.29E-05
1.11E-04
9.46E-02
1.17E-04
2.09E-04
5.60E-07
4.41E-04
-1.72
-1.04
-4.49
21.70
-9.80
21.70
-1.93
4.14E-06
5.10E-07
0.988
1.90E-06
1.90E-06
2.25E-05
1.10E-04
9.05E-02
1.50E-04
1.90E-04
7.15E-07
4.32E-04
4.32E-04
4.60E-06
4.14E-06
10.08
1.45E-04
100
Table D.17. Experimentally determined composition of standard B2 using the plastic clay comparator standard.
Sample B2
Element
Sodium
Silicon
Potassium
Manganese
Strontium
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
Si-31
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Ba-131
Ba-135m
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
Id
> 2 hours
Error ±
Confidence
8 days
1.42E-03
1.73E-04
0.957
2.63E-04
3.89E-01
1.09E-01
0.919
2.46E-02
3.24E-03
0.934
5.92E-02
2.02E-03
2.33E-04
0.938
2.07E-06
2.45E-07
0.981
Error ±
3.26E-05
Id
Confidence
0.991
1.39E-02
0.968
5.98E-07
8.82E-08
0.429
5.05E-05
2.23E-04
5.81E-03
1.30E-04
1.87E-04
1.24E-06
8.84E-04
1.79E-03
1.51E-05
5.87E-06
3.32E-05
7.17E-04
1.71E-05
2.44E-05
1.55E-07
1.11E-04
6.02E-04
1.82E-06
0.99
1
0.987
0.984
0.979
1
0.962
0.891
0.989
23 days
Error ±
Id
Confidence
NIST
Concentrations
1.30E-03
2.43E-01
2.43E-02
1.73E-03
Sample
Concentrations
1.42E-03
3.89E-01
2.46E-02
2.02E-03
Percent
Difference
-9.19
-59.69
-0.98
-16.82
2.60E-06
2.32E-06
2.31E-05
1.07E-04
1.07E-01
1.29E-04
2.09E-04
8.17E-07
8.29E-04
3.46E-07
3.43E-07
2.68E-06
1.59E-05
1.23E-02
1.66E-05
2.71E-05
1.32E-07
1.19E-04
0.417
0.377
0.987
1
0.984
0.983
0.977
0.983
0.96
2.07E-06
-8.78
2.31E-05
1.07E-04
1.07E-01
1.29E-04
2.09E-04
1.24E-06
8.84E-04
-2.47
2.05
-18.14
13.93
-9.87
-73.07
-104.48
4.30E-06
5.18E-07
0.988
1.90E-06
1.90E-06
2.25E-05
1.10E-04
9.05E-02
1.50E-04
1.90E-04
7.15E-07
4.32E-04
4.32E-04
4.60E-06
4.30E-06
6.55
1.45E-04
101
Table D.18. Experimentally determined composition of standard B3 using the plastic clay comparator standard.
Sample B3
Element
Sodium
Silicon
Potassium
Manganese
Strontium
Europium*
Scandium*
Titanium
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
Si-31
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Sc-48
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Ba-131
Ba-135m
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
Id
> 2 hours
Error ±
Confidence
8 days
1.42E-03
1.75E-04
0.949
3.81E-04
4.84E-01
1.18E-01
0.931
2.45E-02
3.25E-03
0.934
4.14E-02
2.06E-03
2.40E-04
0.925
2.23E-06
2.67E-07
Error ±
4.76E-05
Id
Confidence
0.989
1.42E-02
0.972
0.98
4.61E-05
5.4E-06
0.99
1.57E-04
3.98E-03
7.13E-05
1.83E-04
1.1E-06
7.82E-04
3.39E-03
1E-05
2.35E-05
4.68E-04
9.46E-06
2.41E-05
1.37E-07
9.70E-05
1.01E-03
1.21E-06
1
0.987
0.982
0.982
1
0.962
0.904
0.988
1.69E-04
3.7E-05
0.999
23 days
Error ±
Id
Confidence
NIST
Concentrations
1.30E-03
2.43E-01
2.43E-02
1.73E-03
Sample
Concentrations
1.42E-03
4.84E-01
2.45E-02
2.06E-03
Percent
Difference
-9.02
-98.88
-0.70
-18.91
2.50E-06
1.88E-06
2.35E-05
1.11E-02
1.10E-04
1.06E-01
1.28E-04
2.02E-04
1.13E-06
5.84E-04
3.31E-07
2.73E-07
2.76E-06
3.20E-03
1.64E-05
1.23E-02
1.68E-05
2.67E-05
1.66E-07
8.90E-05
0.409
0.375
0.983
0.992
1
0.978
0.977
0.97
0.989
0.786
2.23E-06
-17.46
2.35E-05
1.11E-02
1.10E-04
1.06E-01
1.28E-04
2.02E-04
1.10E-06
7.82E-04
-4.54
-93.09
-0.43
-17.19
14.35
-6.30
-53.72
-80.95
4.26E-06
5.24E-07
0.988
1.90E-06
1.90E-06
2.25E-05
5.77E-03
1.10E-04
9.05E-02
1.50E-04
1.90E-04
7.15E-07
4.32E-04
4.32E-04
4.60E-06
4.26E-06
7.33
1.45E-04
1.69E-04
-16.58
102
Table D.19. Experimentally determined composition of standard B4 using the plastic clay comparator standard.
Sample B4
Element
Sodium
Silicon
Potassium
Manganese
Strontium
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
Si-31
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Ba-131
Ba-135m
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
Id
> 2 hours
Error ±
Confidence
8 days
1.43E-03
1.77E-04
0.946
3.99E-04
3.35E-01
1.21E-01
0.862
2.53E-02
3.40E-03
0.923
2.10E-03
2.47E-04
0.901
2.38E-06
2.9E-07
Error ±
5.16E-05
Id
Confidence
0.986
0.974
23 days
Error ±
Id
Confidence
NIST
Concentrations
1.30E-03
2.43E-01
2.43E-02
1.73E-03
Sample
Concentrations
1.43E-03
3.35E-01
2.53E-02
2.10E-03
Percent
Difference
-9.51
-37.62
-3.87
-21.27
1.89E-07
1.39E-07
2.69E-06
1.66E-05
1.11E-02
1.79E-05
2.79E-05
1.31E-07
8.41E-05
0.392
0.375
0.986
1
0.982
0.982
0.972
0.989
0.785
2.38E-06
-25.23
2.27E-05
1.11E-04
9.48E-02
1.36E-04
2.09E-04
1.22E-06
5.71E-04
-0.79
-0.99
-4.78
9.31
-10.01
-71.14
-32.06
5.65E-07
0.988
1.90E-06
1.90E-06
2.25E-05
1.10E-04
9.05E-02
1.50E-04
1.90E-04
7.15E-07
4.32E-04
4.32E-04
4.60E-06
4.50E-06
2.21
5.84E-05
2.22E-04
5.25E-03
1.03E-04
2.83E-04
1.22E-06
5.71E-04
6.91E-06
3.36E-05
6.25E-04
1.41E-05
3.93E-05
1.57E-07
7.33E-05
0.987
1
0.984
0.985
0.979
1
0.961
1.39E-06
8.86E-07
2.27E-05
1.11E-04
9.48E-02
1.36E-04
2.09E-04
7.31E-07
4.71E-04
1.22E-05
1.50E-06
0.988
4.50E-06
1.45E-04
103
Table D.20. Experimentally determined composition of standard B5 using the plastic clay comparator standard.
Sample B5
Element
Sodium
Silicon
Potassium
Manganese
Strontium
Europium*
Scandium*
Chromium
Iron
Zinc*
Rubidium*
Antimony*
Barium*
Hafnium*
Calcium
Zirconium*
Nuclide
Na-24
Si-31
K-42
Mn-56
Sr-87m
Eu-152m
Eu-154
Sc-46
Cr-51
Fe-59
Zn-65
Rb-86
Sb-122
Ba-131
Ba-135m
Hf-181
Ca-47
Zr-95
Weight Percent and respective error
Id
> 2 hours
Error ±
Confidence
8 days
1.34E-03
1.65E-04
0.938
2.21E-04
2.41E-02
2.03E-03
3.23E-03
2.39E-04
0.919
0.88
2.09E-06
2.54E-07
0.973
Error ±
2.94E-05
Id
Confidence
0.983
23 days
Error ±
Id
Confidence
1.51E-05
1.09E-04
1.35E-03
5.28E-05
4.11E-05
4.66E-07
9.71E-05
1.78E-06
1.64E-05
1.60E-04
7.21E-06
5.53E-06
5.99E-08
1.33E-05
0.986
1
0.982
0.979
0.974
1
0.415
2.32E-05
1.04E-04
9.73E-02
1.56E-04
1.86E-04
9.87E-07
6.84E-04
2.75E-06
1.56E-05
1.14E-02
2.04E-05
2.67E-05
1.65E-07
1.46E-04
0.985
1
0.98
0.981
0.969
0.982
0.785
3.53E-06
4.33E-07
0.988
4.43E-06
5.54E-07
0.987
NIST
Concentrations
1.30E-03
2.43E-01
2.43E-02
1.73E-03
Sample
Concentrations
1.34E-03
Percent
Difference
-2.39
2.41E-02
2.03E-03
0.86
-17.20
1.90E-06
1.90E-06
2.25E-05
1.10E-04
9.05E-02
1.50E-04
1.90E-04
7.15E-07
4.32E-04
4.32E-04
4.60E-06
2.09E-06
-9.88
2.32E-05
1.04E-04
9.73E-02
1.56E-04
1.86E-04
4.66E-07
9.71E-05
-3.21
4.93
-7.55
-3.70
1.86
34.83
77.54
4.43E-06
3.75
1.45E-04
104
Table D.21. Tabulated Mean Character Difference (MCD) Values for Italian Tile Samples.
Bi
Ai
MCD
Sample
139B
140B
141B
142B
143B
144B
145B
146B
147B
148B
149B
150B
151B
152B
153B
139B
X
0.08
0.14
0.10
0.13
0.10
0.28
0.08
0.12
0.15
0.29
0.30
0.37
0.37
0.33
140B
0.08
X
0.14
0.12
0.13
0.10
0.27
0.12
0.17
0.14
0.26
0.26
0.34
0.35
0.27
141B
0.14
0.14
X
0.10
0.14
0.13
0.27
0.15
0.20
0.17
0.23
0.31
0.39
0.45
0.34
142B
0.10
0.12
0.10
X
0.11
0.13
0.33
0.15
0.22
0.17
0.24
0.27
0.34
0.40
0.31
143B
0.13
0.13
0.14
0.11
X
0.12
0.32
0.11
0.18
0.13
0.23
0.22
0.26
0.40
0.25
144B
0.10
0.10
0.13
0.13
0.12
X
0.33
0.11
0.16
0.17
0.26
0.28
0.35
0.33
0.29
145B
0.28
0.27
0.27
0.33
0.32
0.33
X
0.27
0.32
0.22
0.23
0.33
0.36
0.40
0.38
146B
0.08
0.12
0.15
0.15
0.11
0.11
0.27
X
0.17
0.18
0.31
0.31
0.36
0.39
0.34
147B
0.12
0.17
0.20
0.22
0.18
0.16
0.32
0.17
X
0.20
0.33
0.34
0.38
0.36
0.33
148B
0.15
0.14
0.17
0.17
0.13
0.17
0.22
0.18
0.20
X
0.18
0.17
0.24
0.34
0.22
149B
0.29
0.25
0.23
0.24
0.23
0.26
0.23
0.31
0.33
0.18
X
0.18
0.22
0.31
0.22
150B
0.30
0.26
0.31
0.27
0.22
0.28
0.33
0.31
0.34
0.17
0.18
X
0.13
0.25
0.10
151B
0.37
0.34
0.39
0.34
0.26
0.35
0.36
0.36
0.38
0.24
0.22
0.13
X
0.30
0.15
152B
0.37
0.35
0.45
0.40
0.40
0.33
0.40
0.39
0.36
0.34
0.31
0.25
0.30
X
0.22
153B
0.33
0.27
0.34
0.31
0.25
0.29
0.38
0.34
0.33
0.22
0.22
0.10
0.15
0.22
X
105
Table D.22. Tabulated Squared Mean Euclidian Distance (SMED) Values for the Italian Tiles.
Bi
Ai
SMED
Sample
139B
140B
141B
142B
143B
144B
145B
146B
147B
148B
149B
150B
151B
152B
153B
139B
X
0.0134
0.0381
0.0216
0.0459
0.0150
0.1796
0.0094
0.0235
0.0610
0.1407
0.1323
0.2184
0.2304
0.1488
140B
0.0134
X
0.0290
0.0254
0.0255
0.0161
0.1791
0.0194
0.0613
0.0422
0.1159
0.0938
0.1663
0.2312
0.1000
141B
0.0381
0.0290
X
0.0201
0.0410
0.0282
0.2187
0.0392
0.0657
0.0926
0.1395
0.1687
0.2323
0.3444
0.1520
142B
0.0216
0.0254
0.0201
X
0.0291
0.0312
0.2349
0.0462
0.1047
0.0599
0.1100
0.1060
0.1803
0.2534
0.1173
143B
0.0459
0.0255
0.0410
0.0291
X
0.0371
0.2069
0.0277
0.0734
0.0429
0.1104
0.0800
0.1068
0.2812
0.0832
144B
0.0150
0.0161
0.0282
0.0312
0.0371
X
0.2363
0.0210
0.0389
0.0643
0.1316
0.1166
0.2011
0.2214
0.1202
145B
0.1796
0.1791
0.2187
0.2349
0.2069
0.2363
X
0.1941
0.1952
0.0909
0.0897
0.1513
0.1850
0.1978
0.1694
146B
0.0094
0.0194
0.0392
0.0462
0.0277
0.0210
0.1941
X
0.0474
0.0609
0.1475
0.1397
0.1946
0.2647
0.1478
147B
0.0235
0.0613
0.0657
0.1047
0.0734
0.0389
0.1952
0.0474
X
0.1052
0.1825
0.1839
0.2582
0.2551
0.1765
148B
0.0610
0.0422
0.0926
0.0599
0.0429
0.0643
0.0909
0.0609
0.1052
X
0.0439
0.0430
0.0781
0.1802
0.0662
149B
0.1407
0.1082
0.1395
0.1100
0.1104
0.1316
0.0897
0.1475
0.1825
0.0439
X
0.0625
0.0969
0.1620
0.0643
150B
0.1323
0.0938
0.1687
0.1060
0.0800
0.1166
0.1513
0.1397
0.1839
0.0430
0.0625
X
0.0412
0.1292
0.0168
151B
0.2184
0.1663
0.2323
0.1803
0.1068
0.2011
0.1850
0.1946
0.2582
0.0781
0.0969
0.0412
X
0.2508
0.0416
152B
0.2304
0.2312
0.3444
0.2534
0.2812
0.2214
0.1978
0.2647
0.2551
0.1802
0.1620
0.1292
0.2508
X
0.1534
153B
0.1488
0.1000
0.1520
0.1173
0.0832
0.1202
0.1694
0.1478
0.1765
0.0662
0.0643
0.0168
0.0416
0.1534
X
106
Figures D.1-D.13 are scatter plots of the important trace element compositions.
Europium and Rubidium
Rubidium [mg/kg]
7.0E-04
6.0E-04
5.0E-04
4.0E-04
3.0E-04
2.0E-04
1.0E-04
0.0E+00
0
0.0000010.0000020.000003 0.0000040.000005 0.000006
Europium [mg/kg]
Figure D.1. A scatter plot of europium and rubidium trace element concentrations in the Italian
tiles.
Scandium [mg/kg]
Europium and Scandium
4.0E-05
3.5E-05
3.0E-05
2.5E-05
2.0E-05
1.5E-05
1.0E-05
5.0E-06
0.0E+00
0
0.000001 0.000002 0.000003 0.000004 0.000005 0.000006
Europium [mg/kg]
Figure D.2. A scatter plot of europium and scandium trace element concentrations in the Italian
tiles.
107
Europium and Hafnium
1.2E-05
Hafnium [mg/kg]
1.0E-05
8.0E-06
6.0E-06
4.0E-06
2.0E-06
0.0E+00
0
0.000001 0.000002 0.000003 0.000004 0.000005 0.000006
Europium [mg/kg]
Figure D.3. A scatter plot of europium and hafnium trace element concentrations in the Italian
tiles.
Europium and Zirconium
Zirconium [mg/kg]
3.5E-03
3.0E-03
2.5E-03
2.0E-03
1.5E-03
1.0E-03
5.0E-04
0.0E+00
0
0.0000010.0000020.0000030.0000040.0000050.000006
Europium [mg/kg]
Figure D.4. A scatter plot of europium and zirconium trace element concentrations in the Italian
tiles.
108
Hafnium and Chromium
1.4E-04
Chromium [mg/kg]
1.2E-04
1.0E-04
8.0E-05
6.0E-05
4.0E-05
2.0E-05
0.0E+00
0.0E+00
2.0E-06
4.0E-06
6.0E-06
8.0E-06
1.0E-05
1.2E-05
Hafnium [mg/kg]
Figure D.5. A scatter plot of hafnium and chromium trace element concentrations in the Italian
tiles.
Hafnium and Rubidium
7.0E-04
Rubidium [mg/kg]
6.0E-04
5.0E-04
4.0E-04
3.0E-04
2.0E-04
1.0E-04
0.0E+00
0.0E+00
2.0E-06
4.0E-06
6.0E-06
8.0E-06
1.0E-05
1.2E-05
Hafnium [mg/kg]
Figure D.6. A scatter plot of hafnium and rubidium trace element concentrations in the Italian
tiles.
109
Hafnium and Scandium
4.0E-05
Scandium [mg/kg]
3.5E-05
3.0E-05
2.5E-05
2.0E-05
1.5E-05
1.0E-05
5.0E-06
0.0E+00
0.0E+00
2.0E-06
4.0E-06
6.0E-06
8.0E-06
1.0E-05
1.2E-05
Hafnium [mg/kg]
Figure D.7. A scatter plot of hafnium and scandium trace element concentrations in the Italian
tiles.
Hafnium and Zirconium
3.5E-03
Zirconium [mg/kg]
3.0E-03
2.5E-03
2.0E-03
1.5E-03
1.0E-03
5.0E-04
0.0E+00
0.0E+00
2.0E-06
4.0E-06
6.0E-06
8.0E-06
1.0E-05
1.2E-05
Hafnium [mg/kg]
Figure D.8. A scatter plot of hafnium and zirconium trace element concentrations in the Italian
tiles.
110
Chromium and Scandium
4.0E-05
Scandium [mg/kg]
3.5E-05
3.0E-05
2.5E-05
2.0E-05
1.5E-05
1.0E-05
5.0E-06
0.0E+00
0.0E+00 2.0E-05
4.0E-05
6.0E-05
8.0E-05
1.0E-04
1.2E-04
1.4E-04
Chromium [mg/kg]
Figure D.9. A scatter plot of chromium and scandium trace element concentrations in the Italian
tiles.
Rubidium [mg/kg]
Chromium and Rubidium
7.0E-04
6.0E-04
5.0E-04
4.0E-04
3.0E-04
2.0E-04
1.0E-04
0.0E+00
0.0E+00 2.0E-05 4.0E-05 6.0E-05 8.0E-05 1.0E-04 1.2E-04 1.4E-04
Chromium [mg/kg]
Figure D.10. A scatter plot of chromium and rubidium trace element concentrations in the Italian
tiles.
111
Chromium and Zirconium
3.5E-03
Zirconium [mg/kg]
3.0E-03
2.5E-03
2.0E-03
1.5E-03
1.0E-03
5.0E-04
0.0E+00
0.0E+00 2.0E-05
4.0E-05
6.0E-05
8.0E-05
1.0E-04
1.2E-04
1.4E-04
Chromium [mg/kg]
Figure D.11. A scatter plot of chromium and zirconium trace element concentrations in the Italian
tiles.
Scandium and Rubidium
7.0E-04
Rubidium [mg/kg]
6.0E-04
5.0E-04
4.0E-04
3.0E-04
2.0E-04
1.0E-04
0.0E+00
0.0E+00 5.0E-06 1.0E-05 1.5E-05 2.0E-05 2.5E-05 3.0E-05 3.5E-05 4.0E-05
Scandium [mg/kg]
Figure D.12. A scatter plot of scandium and rubidium trace element concentrations in the Italian
tiles.
112
Scandium and Zirconium
Zirconium [mg/kg]
3.5E-03
3.0E-03
2.5E-03
2.0E-03
1.5E-03
1.0E-03
5.0E-04
0.0E+00
0.0E+00 5.0E-06 1.0E-05 1.5E-05 2.0E-05 2.5E-05 3.0E-05 3.5E-05 4.0E-05
Scandium [mg/kg]
Figure D.13. A scatter plot of scandium and zirconium trace element concentrations in the Italian
tiles.