by a sample after irradiation is both
supplied by Sai
Bragg’s law, namely:
a powerful qualitative and quantitacan be found in
2d sin θ = n λ
tive analytical technique. It is based
page), along wi
where integer n refers to the
on the following phenomenon: an
finish, within o
diffraction order.
atom relaxes after excitation by
the best intens
emitting X-ray radiations at specific
promise. The o
wavelengths, which reveal the
each specific ca
TIAP
crystal
Theidentity
spectral of
analysis
of X-rays
emitted by a sample
after
irradiation is both a powerful qualitative
the emitting
species.
reflects the nat
Crystals for X-Ray Spectrometry
and quantitative analytical technique. It is based on the following phenomenon: an atom relaxes
after
excitation
by emitting
X-ray
radiations at specific wavelengths, which reveal the identity of
For
this spectral
analysis
Saintthe Gobain
emittingCrystals
species.supplies two key
components:
For this spectral analysis Saint-Gobain Crystals supplies two key components:
- The
monochromating
crystals
• The
monochromating
crystals
- The
scintillation
detectors
• The
scintillation
detectors
Monochromating crystals
An X-ray spectrometer basically
A monochromating
consists of: crystal behaves in X-ray spectrometry
as does a diffraction grating in optics. When rotated with
• An excitation source which may be
respect to the incident polychromatic beam (see figure), it
- Either
a primary
X radiation,
indirection to
will diffract
the spectral
component
along with
satisfy Bragg’s
law,
namely:
2d
sin
θ
=
n
λ
where
which case one refers to X-ray integer n
refers to the diffraction order.
fluorescence spectrometry.
Hence,- Or
thean most
important
characteristic
electron
beam, inducing
a of a
monochromating crystal is the double atomic spacing 2d,
so-called
direct
emission,
used in
which gives
the largest
wavelength
to be diffracted.
microprobes and scanning
The range of monochromators supplied by Saint-Gobain
electron microscopes.
Crystals can be found in the table (next page), along with
the usual surface finish, within our control means, to the best
•A monochromating
which
is on
intensity-resolution
compromise.crystal
The optimum
depends
each specific
case
and
strongly
reflects
the
nature
used to disperse the various spectral of the
set-up.
components of the incident beam.
An X-ray spectrometer basically consists of:
•A detector in order to measure the
An excitation
source
which
may be
either lines
a primary X
intensity
of the
various
spectral
radiation, in which case one refers to X-ray fluorescence
as singled out by the monochromator.
spectrometry. Or an electron beam, inducing a so-called
direct emission, used in microprobes and scanning electron
microscopes.
The detector offered by Saint-Gobain
Crystals is a Xcrystal
Scintibloc®
A monochromating
which is which
used to disperse the
various
spectral
components
of the incident beam.
combines a Nal(TI) scintillator
directly
coupled
to a photomultiplier
A detector
in order
to measure
the intensity of the various
spectral
lines
as singled
out by the
monochromator.
with
a low
absorbing
MIB
or beryllium entrance
window
(seeCrystals
brochure
The detector
offered by
Saint-Gobain
combines a
Nal(TI)
or BrilLanCe™detectors”).
380 scintillator directly coupled to
“Scintillation
a photomultiplier with a low absorbing MIB or beryllium
entrance window (see brochure “Scintillation detectors”).
Sample
Single
crystalline plate
X-ray generator
Monochromati
suppled in the
- Flat
- Curved onto
Flat plates can
mounted or mo
suitable for ind
cence spectrom
holders may als
request. The st
accuracy provid
special request
accuracy can be
Products available
Monochromating crystals can be suppled in the two
following shapes: Flat or Curved onto a holder
The curved plat
as
Flat plates can be supplied unmounted orinstruments
mounted
into holders suitable for industrial X-ray fluorescence
scanning electr
spectrometers. Other types of holders may also be supplied
always issupplied
on request. The standard orientation accuracy provided
10 minutes. On special request a one-minute accuracy
can
holders.
Natural quartz
be ensured.
Two main type
The curved plates used in such instruments as microprobes
rationsonmay be
and
PETscanning
crystal electron microscopes are always supplied
tailor-made holders.
- The Johann g
Two main types of focusing configurations may be
- The Johansso
considered:
The Johann geometry and The Johansson geometry
3D to
curved
3D curved crystal optics can be provided according
your cryst
special finishing requirements:
provided accord
spherical, toridal, ellipsoidal, conical, others (please
finishing requir
inquire)
- spherical
- toridal
- ellipsoidal
- conical
- others (plea
X-Scintibloc®
θ
Products ava
2θ
CRYSTALS
Natural beryl
Catalogue of Saint-Gobain Crystals monochromators
Lithium fluoride
Crystal
(1)
Chemical
formula
Crystal system
Indium
Antimonide
Quartz
(1)
Silicon
(2)
(1)
Germanium
(2)
(1)
(2)
LiF
SiO2
InSb
Si
Ge
Cubic
Hexagonal (3)
Cubic
Cubic
Cubic
4.027
4.913
6.48
5.431
5.658
Parameters:
a..................Å....
b..................Å....
4.913
c..................Å....
5.405
β.........................
Reflecting
planes
orientations
(200)
(220)
(420)
(1011)
(1010)
(111)
(111)
(220)
(111)
(220)
2d in Å
4.027
2.848
1.801
6.684
8.514
7.480
6.271
3.840
6.532
4.000
Cleaved or
Treated
Treated
Treated
Polished
Polished
Polished
Polished
Polished
Polished
Polished
Reflectivity
Intense
Intense
Average
Good
Good
Intense
Intense
Average
Intense
Intense
Calibration
elements
Mo, Fe, Ti
Mo, Fe
Mo
Cu
Cu
Si
Cu
Cu
Cu
Cu
Common
applications
From K
to heavy
elements
Heavy
elements
Heavy
elements
As
Ge (111)
As
PET
Lines
splitting
Lines
splitting
Quantitative
analysis of
silicon
Usual surface
finish
Pentaerythritol
PET
Ethylene
Diamine
Dextrotartrate
EDDT
Ammonium
Dihydrogen
Phosphate
ADP
Chemical
formula
C(CH2OH)4
C6H14N2O6
Crystal system
Quadratic
Crystal
Extinction of even
order spectral lines
Beryl
Extinction of even
order spectral lines
Acid Phthalates
(2)
Thallium TIAP
Rubidium RbAP
Potassium KAP
NH4H2PO4
3BeO,AI2O3
6SiO2
CO2HC6H4CO2TI
CO2HC6H4CO2Rb
CO2HC6H4CO2K
Monoclinic
Quadratic
Hexagonal
Orthorhombic
Orthorhombic
Orthorhombic
Parameters:
a..................Å....
6.16
8.97
7.530
9.21
6.63
6.55
6.46
b..................Å....
6.16
8.808
7.530
9.21
10.54
10.02
9.61
c..................Å....
8.74
5.959
7.542
9.17
12.95
13.06
13.33
β.........................
105° 33’
Reflecting
planes
orientations
(002)
(020)
(101)
(1010)
(001)
(001)
(001)
2d in Å
8.740
8.808
10.648
15.950
25.900
26.120
26.640
Cleaved or
treated
Polished
Polished or
treated
Polished
Cleaved
Cleaved
Cleaved
Reflectivity
Intense
Average
Average
Average
Intense
Intense
Good
Calibration
elements
Al, Si
Al
Mg
Mg
Na, Mg
Na
Na
Mg
Na and
following
elements
F to Al
Na to Al, up to
F in emission
probes
Na to Al, up to
F in emission
probes
Usual surface
finish
Common
applications
(1) Other cuts can be supplied upon request.
(2) Noteworthy for its high radiation damage threshold (synchrotron).
(3) The quartz unit cell is rhomboedric. The parameters given here correspond to a multiple hexagonal cell, defined as for beryl by
a = b≠c
α= β = 90° y= 120°
May also be supplied on request:
Topaz (303) 2d = 2.712 Å
CsAP (001) 2d = 25.650 Å
applications
s can be supplied
uest.
hy for its high
damage threshold
on).
z unit cell is
dric. The parameters
e correspond to a
hexagonal cell,
s for beryl by
0° y= 120°
upplied on request:
2d = 2.712 Å
2d = 19.800 Å
2d = 25.650 Å
2d = 52.500 Å
Mg
Wavelength λ
Na and
following
elements
F to AI
Na to AI, up to
F in emission
probes
Na to AI, up to
F in emission
probes
Atomic
Number
(Å)
2
1
H
Element
3 113
240
4
Be
Li
11 9.89
11.91
Na
K
20 3.03
38 0.83
55 0.39
39 0.79
56 0.37
57
23 2.29
40 0.75
Hf
42
73 0.21
43
0.67
Mo
74
26
1.94
0.64
6 31.60
B
44
75
0.20
Re
45
0.61
76
0.56
1.44
47
0.18
0.54
13 7.13
79
0.18
1.26
48
49
0.51
0.49
In
80
1.18
50
0.47
0.17
Tl
33
1.11
51
0.45
82
0.16
17 4.19
Cl
34
83
0.16
Bi
Kr
53
0.43
0.42
I
84
85
0.15
Po
58 0.35
0.36
Rare
Earths
59 0.34
Pr
Ce
90 0.13
0.13
Th
60 0.32
Nd
91 0.13
Pa
ADP(101)
92 0.12
U
61 0.31
Pm
62
93 0.12
Np
InSb(111)
0.12
95
Am
LiF(200)
64
0.29
0.12
65
0.28
Gd
Eu
94
Pu
63
0.30
Sm
Tb
96
Cm
Bk
LiF(220)
98
0.11
67
0.26
99
0.11
Cf
Ge(111)
Es
68
0.25
Ho
Dy
97
0.11
66
0.27
0.25
Er
0.10
100
Fm
TIAP(001)
69
Tm
0.15
At
101
Md
0.24
70
Yb
102
No
PET(002)
54
Xe
86
Rn
89
Ac
36
0.98
Br
Te
18
Ar
35
1.04
52
10
Ne
4.73
Se
Sb
Pb
16
S
As
Sn
81
0.17
Hg
32
9 14.62
F
15 5.37
P
Ge
Ga
8 18.30
O
14 6.16
Si
31
1.34
Cd
Au
Pt
30
Zn
Ag
78
0.19
Ir
29
Cu
Pd
77
0.19
1.54
46
0.59
Rh
Os
28
Ni
7 22.71
N
C
8.34
1.66
Co
Ru
0.20
27
1.79
Fe
Tc
W
Ta
25
2.10
Mn
41 0.71
Nb
72 0.22
0.22
24
Cr
V
Zr
La
88 0.14
Ra
22 2.51
Ti
Y
Ba
87 0.14
Fr
21 2.75
Sc
Sr
Cs
0.15
5 44
67
12.394
E(keV)
Al
Ca
Rb
0.40
λ(Å) =
12
37 0.88
0.93
2d sin θ = nλ
Alternative
Crystal
Mg
19 3.36
3.74
Usual
Crystal
He
0.23
71
Lu
103
Lw
Crystals for X-Ray Spectrometry
The Johann geometry
A thin plate, produced by one of the two following
methods:
• Cleavage for LiF (200)-PET-TIAP-RbAP-KAP
• Machining for other materials, is further cylindrically
curved and glued upon a holder of curvature radius
2R. It is possible to show that a beam emitted by a
source at S is approximately focused at F. The source
and focus are both located on the so-called Rowland
circle whose radius is R
The Johansson geometry
Two different types of Johansson configurations,
theoretically leading to perfect focusing, are considered:
• Single machining Johansson
• Double machining Johansson
The illustrations represent the fabrication steps of
Johansson plates in both techniques.
Saint-Gobain Crystals will choose the most appropriate
technique according to the type of crystal, its dimensions
and the radius of Rowland circle to be achieved.
The orientation accuracy is better than 10 minutes, except
for the Johann cleaved configuration, where it is 1 minute.
Other types of curvature may be investigated on request.
For example, curvatures on holders shaped as logarithmic
spiral, elliptic, parabolic, even spheric designs, interesting
in plasma or synchrotron radiation study and astrophysics.
Manufacturing capabilities will strongly depend upon the
crystal nature and dimensions as well as on the curvature
radii.
Saint-Gobain Crystals
www.crystals.saint-gobain.com
Manufacturer reserves the right to alter specifications.
©2004-2016 Saint-Gobain Ceramics & Plastics, Inc. All rights reserved.
(08-16)