Title
Author(s)
Citation
Issue Date
URL
Paper VII Radiochemical Analysis of the Bikini Ashes (The
Radioactive Dust from the Nuclear Detonation)
Ishibashi, M.; Shigematsu, T.; Ishida, T.; Okada, S.; Nishi, T.;
Takahashi, H.; Matsumoto, C.; Shimizu, S.; Hyodo, T.;
Hirayama, F.; Okamoto, S.
Bulletin of the Institute for Chemical Research, Kyoto
University (1954), 32(s): 39-59
1954-11
http://hdl.handle.net/2433/75484
Right
Type
Textversion
Departmental Bulletin Paper
publisher
Kyoto University
PAPER VII
Radiochemical
Analysis
of the
Bikini
Ashes
M. ISHIBASHI,T. SHIGEMATSU,T. ISHIDA
(Ishibashi Laborary, Institute for ChemicalResearch, Kyoto University)
S. OKADA, T. Nisxt, H. TAKAHASHI,C. MATSUMOTO
(ElectrochemicalLaboratory, EngineeringResearch Institute, Kyoto University)
and
S. SHIMIZU, T. HYODO, F. HIRAYAMA,S. OKAMOTO.
(Nuclear Research Laboratory, Institute for Chemical Research, Kyoto University)
I. INTRODUCTION
Radioactive ashes produced by the hydrogen bomb test at Bikini Atoll on
March 1, 1954 happened to fall on a Japanese fishing boat, t1to No. 5 Fukuryu
Maru, which was then approximately 90 miles from Bikini.* Twenty-three crew
members on board suffered from radiation sickness by this accident, which was
brought to light after the boat returned to her home port of Yaizu on March 14,
1954. The present work was undertaken because it was then urgently necessitated
to disclose the nature of the radioactive ashes in order to obtain some knowledges
which might be valuable for the medical treatment for the afflicted fishermen.**
Two methods were employed to separate and assign the elements in the ashes.
The one is the combined method of the usual analysis employing carriers and separation with the ion exchanger. The other is the method using only the ion exchanger. After the chemical separation the assignment of nuclides was carried out by
observing the radioactive properties of the species by means of the end-window G-M
counters and the scintillation counter.
A brief account of the study on radioactivities in the rain at Kyoto on May 16 is also given in the fourth chapter of this paper.
II. PHYSICAL MEASUREMENTS
1. Apparatuses
The physical assignment of the nuclides separated chemically was made by the
determination of 13- and y-ray energies from the samples by the absorption method
using end-window G-M counters and a scintillation counter. The end-w indow G-M
counter used in this work had the cathode with an inside diameter of 20 mm and a
* This position was outside the demarcationof the "danger zone" from which the United
States had long since warned all shippings.
** On this occasion the authors wish to express their deep appreciation to Prof. T. Shiokawa of Shizuoka University, Prof. K. Kimura of Tokyo University, I )r. T. Maekawa,
Chief of Sanitation Division of Shizuoka Prefecture, and staffs of Yai ;u Municipal Office for their kind aids in collecting the radioactiveashes from the No.5 Fukuryu Marg.
( 39 )
,
M.ISHIBASHI,
S. OKADA,S. SHIMIZUet al.
mica window of 3 mg /cm' or 1.5 mg/cm' in thickness-fr. The scintillation counter**
used for r-ray absorption had terphenyl in xylene solution as a phosphor . Pulses
from the counters were measured with a scale-of-100 scaler with a mechanical recorder .
Some precautions were taken to keep the standard error in the counting rate for each
measurement below about 3 per cent.
The G-M tube and shelf assembly and the arrangement of y-ray absorption
with the scintillation counter are shown in Figs. 1 and 2, respectively.
/H:T.
P.MPLI
FIER
PIDOUTPUT
/1[4 G.M.
COUNTER
_../
//ENVELDPE
MICA
WlN•Ow-------------'
/
AI
A850RBERand1
1"-g-//--,
~'~3rd
SAMPLE
MOUNTED4th
ON
THIN
MICASthIli)
%,
1st SHELF
N
6th
~~
0PHOSPHOR------------------a o_ 00
-
Pb ABSORBER
O34
Fig. 1
6SAMPLE
CM
.
, r Ayi iri ,./I (4
G-M •counter and shelf assembly'""Fig.
for f3-ray absorption.by
* Manufactured
2
Arrangement of 7-ray absorption
the scintillation counter.
by Kobe Kogyo' Co. L'td., Kobe , Japan : GM-131 (3 mg/cm2) and GM-132
(1.5 mg/cm2).
** Manufactured by EKCO Electronics
Ltd ., Southend-on-Sea,
( 40
Essex, England: Type N502
RadiochemicaI Analysis of the bikini Ashes
2.
Determination
The
thickness
of 19-ray energies.
determination
of g-ray
for aluminum
cation of the Feather
ween half-thickness
energies
was carried
and by estimating
method
the total range in aluminum
of analysis.
and energy,
out by observing
The empirical
used in the present
the half-
by the appli-
curve for the relation
work,
was obtained
bet-
in such a
geometry that the samples were placed on the 2nd shelf and the absorbers on the 1st
shelf, by using C14, P32, Co", Sr" and P31 which were available in our laboratory.
This
geometry
method
of measurement
is applicable
samples we applied the Feather
the
was
for the samples
analysis,
3rd shelf while the absorbers
necessary
for this method
a reference
species,
the ion exchange
this purpose.
which
low intensities.
The
by observing
analyzer
absorption
from the fission products
spectrum
as possible,
the
1
1
1
0_•FEATHER
-•Y,'
2---43
1
due to the
sample
and purified by
generally
used for
backscattering
of g-
I
I
I
ANALYZER
STRIP ------42
FEATHER
RANGE
740MG/CM>''
— 44
—----as
w
t —
cc z—
zz
Z
------ 46
Z
-----R7
US
— 0$
10
5R ------49
0
I1IH
100
strip
of V1 as
was placed on a thin mica
J3
z10—
on
in Fig. 3 and Table 1.
of the g-ray
I
For some
were placed
Feather
the g-ray
since we were not able to use RaE,
holder
'04
on the 1st shelf.
prepared
This is illustrated
sample
by the reason that the half-thickness
in such cases the samples
was separated
technique,
To avoid the variation
rays . from the
was
decided
with comparatively
200
300
11111
400
500
600
700
000
700
Al ABSORBER
, MG/CM'
Fig. 3 Alminum absorption curve of the g radiations of Y91• O,
values in the column A ; o, values in the column B in
Table 1. Strip on right side represents the Feather analyzer
for the standard counting arrangement. Source is on the 3rd
shelf with absorbers on the 1st shelf.
( 41 )
M.ISHIBASHI, S. OKADA, S. SHIMIZU et at.
Table 1. Relative counting rates through absorbers for the Feather
analysis of standard absorption curve of Y91.
mg/cm2A
Bmg/cm2AB
010000
13.48889
25.048423
46.77091
70.26186
95.25115
129.64065
9996164.73192
8885199.82409
8419259.21326
7087324.0679.5
6182423.9197.4
5111540.037.3
4061610.213.7
3188
2405
1322
674.5
193.4
34.3
9.7
A : counting rate (natural background is subtracted)
B : counting rate (the background of the scattered radiation is subtracted)
sheet less than 5 mg/cm'
in thickness
was dropped on the mica sheet
absorption
and self-scattering
large amount
as shown in Fig. 1.
and
evaporated
into
of organic compounds,
the volume to be measured.
The sample in solution
to a thin
consideration.
layer,
When
it had to be decomposed
taking
the
self-
the sample contained
a
with HC1O_, to reduce
In addition to this, since the absorption
in the counter
window is marked for low energy j3-rays, a G-M counter
with a mica window of 1.5
mg/cm'
However,
was used for the
cautions
the reliable
not be obtained.
chapters
were obtained
0.3 Mev.
for the /3-ray energies
curves shown in the figures
of nuclides
by the determination
when the unknown
was not extreme
higher than those of the main nuclide,
were subtracted
the absorption
in the following
of /3-ray energies
sample to be measured
species. When the contamination
were considerably
in spite of these
below 0.15 Mev could
by these procedures.
assignment
be quite troublesome
tamination
curve
The /3-ray absorption
The physical
radioactive
(3-rays less than
absorption
contains
some other
and its /3-ray energies
the counts due to the con-
from the original curve as the background.
curve of Zr" containing
may
For instance,
the rare earth of about 50 per cent is shown
in Fig. 15, while in Fig. 22 that for the purified
sample is shown,
which
contains
still the rare earths of about 2 per cent.
3.
Determination
of r-ray
energies.
Often we could not ascertain
by the
contained
the
r-ray
The
measurement
the daughter
kind of nuclide
products.
especially
existed in the
in the case that
In such cases it was often
helpful
sample
even
the sample
to measure
energies.
determination
using a scintillation
of r-ray
counter
By this procedure
tion curve for r-rays
energies
with terphenyl
2.5 cm in depth, as a phosphor.
2.
what
of (3-ray absorption,
was performed
by the absorption
in xylene solution,
The arrangement
5 cm in diameter
of the apparatus
daughter
(42
of Bal}0, was obtained
)
and
is shown in Fig.
the curves in Figs. 21, 23 and 25 were obtained.
from Lai",
in lead,
The absorp-
by observing
Ba
Radiochemical Analysis of the Bikini Ashes
sample after the radioactive
4.
Measurement
equilibrium
of both nuclides had been attained.
of decay.
The decay of the Bikini Ashes and several species separated
ashes was measured
by the end-window
purpose was constructed
as shown
G-M counter.
in Fig. 4.
I
1
1
The
chemically from the
The special assembly for this
sample,
placed
on an alumi-
1
i1
I I.'
IL
i
1
u;
11
1
0,,/
G-U
COUNTER
'c`n.n
sMPLE02.4
6
SAMPLE
HOLDER
I 1 1 1 1 1 1
(ALUMSNLUM
PLATE„CM
Fig. 4
num
plate,
a fixed
1 mm in thickness
position.
all over
the
sensitivity
The
period
of the
counter
error
decay
curves
were
A
and
where
A, is the
maintain
by
samples
activity
we could
The
of two
sion ; the
and 5 cm x7 cm in size,
was
probable
has been
for decay measurement.
measurement.
The
grey,
arrangement
device
decay
was dark
for the
By such
of the
sources.
Counting
calibrated
in each
of the
measured
obtained
derived
rate
Ashes,
are shown
from
activity
in Fig.
the
~0.05
at time
4, i.e.
t after
for the
the
( 43 )
white
the
64th
day
white
dark
2 per cent.
and
after
empirical
interval
the
the
and
other
explo-
expressions
of 81 days
ashes,
grey
of the
U,,OS reference
less than
was
to
constant
variation
one
for the
guide
geometry
Co0O and
5. Following
explosion
in the
day-by-day
was kept
our measurements
—1.17±0.02
~=Aotfor
A,= Aot-1.24
slight
Bikini
May
the counting
employing
counting
since
was inserted
ashes,
Ao is a constant.
:
M.ISHIBASHI,
S. OKADA,
S.SIDMIZU
et al.
2\
HITE
4500 —
4000 —
3500 —
t s Aot`
_,:+so.o5 A
3000 —(0ARKGREYA5HES)
1— 2000 —
1500 —
I000-r
60
I I I I I I III
I',
'70 SO 90 100 120 140 160
OECAYTIME, DAYS
Fig. 5 Decay curves of the BikiniAshes.
It may be interesting to compare our expressions with the similar one given by
other workers for fission products of U235by the irradiation of slow neutrons.1,2)
The decay curves obtained for YJ', Bai-"-La110,and U=37are shown in Figs .13,
26 and 29, respectively. Our half-life of U237is in good agreement with that given
by other workers,3) however, that the half-life of Ba10 from our data in Fig. 26 is
slightly larger than the value given by other workers,0 may be explained by the
presence of some impurities.
III. ' CHEMICAL ANALYSIS
1. Preparation of sample
The sample gathered from the deck of the No. 5 Fukuryu Maru was dark grey
dust which contained wooden pieces and iron rust. The radioactivity resulted from
the fission products attached to small fragments of coral reef of Bikini Island. The
decay of its activities was measured as shown in Fig. 5, and the Q-ray absorption
curve observed is shown in Fig. 6. The sample was moistened with dil. NaOH and
ashed in a porcelain crucible. The ashes were fused with Na2CO3—KOCO3,and the
fused mass was treated with hot water and digested on a water bath for one
hour. After the complete elimination of the phosphates had been ascertained with
ammonium molybdate, the sample was taken up with conc. HC1. Carrier solutions*
* Nitrates of Se, Y, Zr, Nb, Sr, Ag, In, Rh, Sb, Ba, La, Ce, Pr, Nd, Er and Yb.
Chlorides of Pd, Cd and Sn. 1/100m. mole of each element was added.
( 44 )
—
}
S
Radiochemical
Analysis
of the Bikini Ashes
to_---------------------------------------------------------------------I
(
I
I
I
=
s-
31--
S
•-
U 1—
•
} 103
1-•
>
~ s
u•—
••
Q
a•
i0
0
I
300
I
GOO
I
900
I
1200
1500
Al ABSORBER
, MG/CM
Fig. 6 Aluminum absorption curve of the Bikini Ashes.
(Dark grey ashes, March 25, 1954)
were added and evaporated
to dryness on a water bath.
In our analysis the special precaution
was taken to remove the silicates completely
in order to avoid the following difficulties
coarse grained
ion-exchange
would pass through
resin,
the exchanger
: In the separation
the colloidal silica, carrying
so that radionuclides
of elements
radioactive
using the
species,
would be eluted irregularly,
accompanying undesired contaminations.
When the fine grained ion exchange resin
is used, the colloidal silica would be left on the upper part of exchanger bed, adsorbing considerable
2.
The
illustrated
the
portion of radionuclides.
Analysis by the method
group
separation
of the conventional
was carried out by the conventional
in the flow sheet shown in Fig. 7.
ion exchange
technique
was also applied.
a)
group :
The
NH2OH,
dryness.
The
first
grouping.
residue
For further
insoluble
H,S
separation
method,')
as
of each group,
in 4N HC1 was taken up to dil.
then NaOC1 solution was added to the filtrate, followed by evaporation to
This sample was identified as
by measuring the ,8-ray absorption
as shown in Fig. 8.
b)
The second group :
the elements
The acidity of the solution was adjusted
of the second group were precipitated
( 45
as sulfides,
to 0, 3N, and
ISIEBASHE, S. OKADA, S. stimuzu
Sample
et al.
fused with alkali carbonate
H- MCI
PrecipitateFiltrate
1st group
<--H2S
PrecipitateFiltrate
2nd group
4-NHIOH
A--(NH,)2S
11
PrecipitateFiltrate
3rd group
(boil)
-NH4OH
NH 1)2CO3
PrecipitateFiltrate
4th group5th
Fig. 7
Flow sheet showing analytical
the radioactive dust.
procedure
1\
group
for group separation
of
10_--------------------------------------------------------------- I
—2—
0 5
2
= 16,5MG/CM
—
( o.6 mEv)
2-
<
10=
lo
—
1 3060
90
Al ABSORBER,
MG/CA42
The
sulfides
aminobenzylidene
solution
were
Fig. 8
Aluminum
absorption
dissolved
in HNO3.
A saturated
rhodanin
at pH 1. O.
The
was
added
precipitate
curve of 1°'.
drop by drop
of Pt-group
alcoholic
under
separated
solution
vigorous
of p-dimethyl
stirring
by this procedure
to
the
had no
activity.
Se and Te were
reduced
to the metallic
I 4
_
state
)
with ferrous
sulfate
and
hydrazine
Radiochemical Analysis of the Bikini Ashes
hydrochloride
solution,
respectively.6>
too weak to measure
its energy.
Te, Te129 was assigned
The
radioactivity
By observing
of Se obtained
the Q-ray absorption
here was
of precipitated
as shown in Fig. 9.
I
I
I
I
I
I
2——
la—
2
2—
^ 2`•
to .
>-
F
•
CONTAMINATION
BACKGROUND. Q •2
——
10—1),i
- = 54MG/CM2(1,6MEV)
2—
I
o
I
SO
I
100
I
150
I
200
I
250
I
300
I
350
Al ABSORBER
, MG/CM'
Fig. 9 Aluminum absorption curve of Tel 9",-Tel"-9.
C, original points. o, contamination background
subtracted.
The organic matter in the filtrate was decomposed by treatment
The
residue was
solution
Cu-group
c)
taken
was saturated
up with
with
HC1 and the acidity was
H,S ; no activity
with conc. HNO3.
adjusted
to 0.3 N.
was found in the precipitate
The
of the
thus obtained.
The third group :
third group was precipitated
Using the filtrate
from the second group elements,
as sulfide. The HC1 solution of the third group at a pH
of 1. 0 was adsorbed on the resin bed (120 cm x1.13 cm') of the
IR-120 (40-.60
After washing
mesh),*
and
the
width
with water, radioactive
solutions successively
the
of the
species
adsorption
were
eluted
H-form
Amberlite
band was about
out using
5 mm.
the following
at a flow rate of 1.0 ml/min/cm2.
* Ion exchange resin beds used in the present work were prepared as follows: Amberlite
IR-120 resin was crushed and shieved to the suitable size for each elution. After the
resin was warmed with 4N HCl on a water bath to convert it into H-form and to
swell, it was packed in a pyrex glass column, bottom of which was closed by glass
wool, as shown in Fig. 10. The resin bed was washed with 1N FIC1,and then with
water to remove the excess HC1 completely.
( 47 )
•
M.ISHIBASHI,
S.OKADA,
S.SHIMIZU
et al.
Orderof elutionElutriant
Elutedspecies
10.2N
HNO3
Radiocolloids
20.5%
Oxalicacid(pH 1.7) Fe and Radiocolloids
359
Amm.-citrate(pH 3.85) Rareearths
The each10ml fractionof effluentwas receivedin cruciblesandevaporatedto drynesswith additionof H"O"and HC1O.,
to decompose
the organiccompound.
The eluateof rare earthsdriedwasagaindissolvedin HC1andpHwasadjusted
to 1. Then,it wasadsorbedon the ionexchangerbed (45cm x 0.50cm') of the
H-formAmberliteIR-120(150-250mesh),as shownin Fig. 10.
t
`.
STORAGE
BOTTLE
aINFLUENT
SOLUTION
PLASTie TUBE
IGLASS
WOOL
•
RESIN EEO
ni GLASSWOOL
I
OCRUCIBLB
Fig. 10 Resin column : the flow rate is adjusted by
varying the height of the storage bottle.
The rare earths were eluted with 5 0o citrate
0.08'0.1m1/min/cm"
of 30 minutes.
solution
(pH
3.2) at a flow rate
of
"). The effluent was collected in porcelain crucibles at an interval
The "cut"
in each crucible was dried and activities were measured.
The elution curve of active rare earths is shown in Fig. 11.
A few "cuts"
respectively,
corresponding
curves were obtained
shows
to each peak in the
and treated with HC1O., and evaporated
for these dried residues
the decay observed for Y".
elution curve were collected
to dryness.
The 13-ray absorption
as shown in Figs. 12 and 14.
By these physical
measurements
Fig. 13
Y91, Pr'}; and
Ce"4 were assigned.
The eluted
radiocolloids
were
treated
( 48 )
with
H,0,-HClO4,
and
the
excess
of
Radiochemical
Analysis of the Bikini Ashes
yqi
CO+4-Pr1++
f- RAYS
U101—
>. F
>
F
U
Id—Y-RAY
CITRATE5%
CITRATE
PH
3.3PH
j0
0
Fig. 11
3.4I
III
50010001500
VOLUMgof ELUATE, ML
Separation of the rare earths in the Bikini Ashes by eluting
through 150- -250 mesh Amberlite 1R-120 ; bed dimension
45 cm x 0.50 cm2 ; flow rate 0.1 ml/min/cm2.
For 7-ray
curve the noise of the scintillation counter is subtracted.
,o+-----------------------------------------------------------------------------------------------------------I
II
II
5—
-•
•
2—/2y=
IL
U
r
H
S0 MG/CM2
( 1,b MEV) r
—
—
—
—
_s
u
s-
120III1I(I
0
100200300400500(50700900400
Al ABSORBER,
Ma/cm2
Fig. 12 Aluminumabsorption curve of Y91.
HC10., was expelled by evaporating with several portions of HCI. Ammonium
hydroxide was added and the precipitate was fused with alkali carbonate for three
C.49 )
•
M.ISHIBASHI,
S. OKADA, S. SHIMIZU et al.
4000 —
3500 —
T~=53ti0d
U 3000
—
I- 2500—
0
U
$ 2000
—
1500
4
I
5
I
r0
I
I
I
I
1
1
IS 20 25 30 35 40
DECAY TIME , DAYS
Fig. 13 Decay curve of Y°1.
I
45
I,
SO
104
•
10'
FEATHER
RANGE
1600MG/CM
3.1MEV)
2x
5
FEATHER
ANALYSIS
I)
5""----------------------11(IIIII_
z S20o
I 2°°
F
-ifoo—
z
2
10
,
20
•
t'"41214IO6la1
0
FRACTION
OF
RANGE
&10
IAO
100
1200
15'00
AI ABSORBER MG/CM'
Aluminum absorption curve and Feather analysis of
CeII4 Pria4 equilibrium mixture. 0, original points.
Fig. 14
y background subtracted.
Feather analysis
S radiations (3.1 Mev) of Pr14 .
hours.
The
fused
natant
was
acidified
was washed
this
sample,
with
mass
was
with
1N NaOH
a little
excess
dil. HC1 several
times
and
dried.
were
too
weak
because
with
leached
its activities
shows
on a water
of HC1 to precipitate
( 50 )
Nb
could
to measure.
bath,
and
hydrated
not
be
the super-
Nb205,
which
identified
However,
in
Zr was
Raciochemical
isolated
,3-ray
from
the
absorption
residue
curve
with
Analysis
tannic
of Zr"
acid according
is shown
I
I
of the Bikini Ashes
in Fig.
to the
Scholler
method.^)
The
15.
I-------------------------------------------------------------------------------------------------------I
I
I
s2
104
U
•
F 3
> 10•
a
sCONTAMINATION
BACKGROUND
2
e0
n
z
1O
0
I
50
I
100
I
150
I
200
I
I
2502300
I----------------------------------------------------------------350
Al ABSORBER
, MG/CM
Fig, 15. Aluminum absorption curve of Zri5, 0, original
points. .., contamination background subtracted.
d)
the
The fourth
fourth group
by coprecipitation
and evaporated
Alkali
were precipitated
were adsorbed
The
and contaminations
of the fourth
of
were removed
group was dissolved in HC1
the residue was taken up with 0.3N NI-140H.
on the
NEL-form"° Amberlite
band being about 5 mm.
separated
Then,
from the third group, the elements
as carbonates
with FeS. The carbonate
to dryness.
earths
containing
group : Using the filtrate
ion exchanger
IR-120 (100--150
bed
mesh),
the
flow rate was 0.1 ml/min/cm'.
(30 cm x 0.28 cm')
width
of adsorption
Alkali earths
were
with the following elutriants.
Order of elution
The elution
ElutriantEluted
1
1.3 N Amm.-acetateCa
2
2 N Amm.-acetateSr
3
ETA 5 ml + 2 N Amm.-acetate
5
ml + Ammonia (1 : 1) 2 ml
curve of alkali earths
is shown in Fig. 16.
weak to assign the nuclide.
( 51 )
Species
Ba
The activity
of Ba was too
M.ISHIBASHI,
S. OKADA,
S. SHIMISU
et al.
Sr
U
y
5
H
CI
Q
0-1
0
/.N/10100A,
i
3NNIMMc(=71
i 1I~
100 200 300400
500 600
VOLUME
of ELUATE,
ML
Fig.16 Separation
of the alkaliearthsin the BikiniAshesby
complex
elution: Amberlite
IR-120(100'-150
mesh); bed
dimension
30 cmx0.28 cm=; flowrate 0.1m1/min/cm"; elutriant,1.3Narnm.-acetate
for Ca,2 Namm.-acetate
for Sr.
The 19-rayabsorptioncurvesof Ca45andSr" are shownin Figs.17and 18,respectively.
_1
i
5—T~=
1
i
i—
sI
5 MG/CM—0
I
5_~;=68
I
I
MG/CM2
F—(0,25MEV)—F—(i.SMEV)
_
>
2>
E-1•-
Z——
s——
0
s——
i0
20
30
40SO
Al ABSORBER
`, MG/CM'Al
separated
was observed in Na and K fractions,
(52)
I
150
I
200
ABSORBER
, MG/Ctvf
from the fourth group, most part of Na
with methyl acetate
0
I
100
Fig. 18 Aluminum absorption curve of Srs5.
The fifth group : Using the filtrate
and K were successively
activity
I
50
60100
Fig. 17 Aluminum absorption curve of Ca;5.
e)
-
and tartrate,
while the residual
respectively.
No
part had so weak
Radiochemical Analysis of the Bikini Ashes
activity
that Rb and Cs could not be identified.
3. Analysis by the method of the ion exchange
The group separation
foot-note
analysis
a)
was carried out by the use of ion exchange
in page 47), since
of radioactive
with H,02-HCIO.2
The residue
this technique
rain-water,
Group separation
was
as mentioned
of radioactive
in the following
to decompose the organic matter,
was taken up with several portions
solution
changer
bed (20 cm x0.28 cm2) of Amberlite
was adjusted
was carried
successively
found to be very
technique
(cf.
effective for the
chapter.
species : The radioactive
chloride
separation
grouping
dust
was
treated
and the solution was evaporated.
of conc. HCI, and the acidity of the
to pH 1, which was then adsorbed
IR-120 (100-150
out by passing the following
elutriants
on the ion ex-
mesh).
The
through
group
the column
with a flow rate of 0.2m1/min/cm'.
Order of elution
ElutriantEluted
1O.
iN HCIAnions
20.5%
Oxalic acidRadiocolloids
35%
4596
Each "cut"
rated to dryness.
Species
Amm.-citrate
(pH 3.85)
Rare earths
Amm.-citrate
(pH 5.90)
Alkali earths
(10 ml) of the effluent was collected in porcelain crucibles and evapoThe 13-ray activity
of each crucible
was measured
and the result
RARE
EARTHS
I04v
RADIOCOLLOIDSSrFig.
19
03Group
separation of the radioactive
elements in the Bikini Ashes by an
)-ion
t-(100,-150
exchanger : Amberlite IR-120
mesh) ; bed dimension 20
cmx0.28 cm2 ; flow rate 0,2 ml/
min/cm2 . ANIONS
"B
F
IoZ
0.11'411C1
lO1(PH
O.E9; 5%5%
OXALIC
ACID
CITRATE CITRATE
3.2.5,PHMO
200400
600800
VOLUME
aF ELLATE, ML
( 53 )
•
M. TSHIBASHI,S. OKADA, S. Su!MIzU et al.
is plotted
b)
in Fig.19.
Assignment
of Ru and Rh : The eluate of the anion group was evaporated
on a mica plate.
From
observation
of the (3-ray and r-ray
sample, Ru103 Rh10sm Ru10f and RhLO°were assigned,
105
I
I
{
I
5FEATHER
I
absorption
for this
as shown in Figs. 20 and 21.
=
ANALYS
IS
25—5
2—
10i0p0
11111
~'1500EW—
1
111
04,2xq4 4i 4fi3O2
FACT/ON
OFRANGE
522
=
~
1oTr=
..—°
5.3 G/CM2
(0.56 MEV)
1.50 CM
FEATHER
RANGE • .
U5
—
2r
Q
9ACKGROUND——
1(,
5—
2—
2—1
I
5
0
100
300
600
600
-
_
IO
15
20
25
30
Pb. ABSORBER
, o/CM2
12001500
Al ABSORBER
MG/CM'
Fig. 20 Aluminum absorption curve of Ru102-Fig.
21 Lead absorption curve of
Rhlos,n Rulos_Rhlosequilibrium mixtureRu103_Rhlo3722
equilibrium
which was separated chemically asmixture.
Curve shows
Ruthenium. Feather analysis shows $7-rays
of Ru1°3.
radiations (3.5 Mev) of Rh106.
c)
Purification
evaporated
of Nb and Zr :
with HCIO.1 to dryness to decompose
residue was moistened
chlorides,
The oxalate
solution of Nb and Zr eluted was
organic materials
and dried several times with
completely.
HC1 to convert
The
Nb and Zr into
and taken up in 10 ml of 6N HCl. From this solution Zr-Nb was extrac-
ted as cupferrate
with cupferron
with CHCl39>, and then returned
and HCI.
than that obtained
As shown
by tannin
to aqueous phase after
washing
in Fig. 22, this sample was less contaminated
method
(cf. Fig. 15).
Gamma-ray
absorption
curve
materials
in the
for this sample is also given in Fig.23.
d)
Assignment
effluent,
of Ba :
After
Ba was precipitated
as carbonate
From the alkali earth mixture,
at low temperature10).
the
decomposition
accompanying
the
j-
and
( 54 )
with HCI-ether
r-ray
thus Ba11' and Lan0 were assigned.
Ba140-La140 is shown in Fig. 26.
•
other alkali earth elements.
Ba was isolated by treatment
Figs. 24 and 25 show
for this sample, respectively,
of organic
absorption
(1:1)
curves
The decay curve of
>
Radiochemical Analysis of the Bikini Ashes
°
I
I
II----------------------------------------------------------------------------------------------------------------------------I
=104=I
!
I
I
I
I
S
—
5—
—
I—
3 •2——
F5\—
010
——
3
_mI.02CM
1
F
IO=-—o
>I-5--a~(0.78MEVf,--
-
2——
x—
U
r BACKOROUND
10 --
>Noyrao\x=5——
Ti.10MG/CM'
°1c
MEV) 'Q0ok0
x
o
s(0,4
-.--_——
—
2—
2—
I
I
!! 200 250
I 2300
I
TO
100
150
0
Fig.
1
to0
Al ABSORBER
,MG/CMPb300
22 Aluminum
04—
absorption
curve
of Zr95.Fig.
Q, original
subtracted.
points.
x , y background
n, y and contamination
background
subtracted.
II
1I
I
I
I
5I
I
10
I
I
I
1 '
30
IS
25
ABSORBER
, 20G/CM
23
Lead
-
I
absorption
I
curve
I
I
I
IS
I
20
of Zr95-Nb05.
I
I
f —-
I
—
—10
4—
s——
u Ia=
—-O(163MEv)
_/0.=O,SSCM_
—'
—z——
—
F--'1d_.
¢-uu5—•—
d¢—•
-r
y.3SMG/C_—
5(1
MEV)-—
—a
10—
5——
o.
0
I
;00
I
200
I
300
Al
I
40J
I
500009
I
I
ABSORSER, MG/CMz2
I
——
a0_
1005
I
I
i0
I
2530
I
I
3E
Pb ABSORBER
. GAM.'
Fig. 24 Aluminum absorption curve ofFig.
25 Lead absorption curve of Ba1t0-Laln°
Ba=k°measured immediately afterequilibrium
mixture. Curve shows
separation.7-rays
of La130.
( 55 )
—
d
M.ISHIBASHI,
S. OKADA,
S. SHIMIZU
et al.
6
4:
•
o.
••
214,9tA:7$
2
0
1-~.
1-
'3
4
6
0
2
0
10
20
30
40
50
60
DECAYTIME, DAYS
Fig. 26 Decay curve of Bala-Lam.
00
30
4. Separation of U'-?7by paper chromatography
One drop of the concentrated sample solution (cf. 3-a) was spotted on a paper
strip (Toyo Filter Paper, No.50), and developed by HC1-butanol solution (1 : 3) for
16 hours at room temperature. The (3-ray activity of the strip was measured by an
end-window G-M counter through a slit of 5 mm width slotted in a lead sheet of
2 mm thickness. The result is plotted in Fig. 27. An intense peak of activity was
found at the position corresponding to Rf =0.54. The 113-rayabsorption curve and
decay curve of this activity are shown in Figs. 28 and 29, respectively.
It may be interesting to note that from these results the activity of this peak
seems to be attributed to 11237,which emits f3-rays of 0.24 Mev and has the half-life
of 6.63 days3).
IV. ANALYSIS OF RAIN-WATER AT KYOTO CITY ON MAY 16, 1954.
The rain-water at Kyoto City on May 16, 1954 was found to have intense radioactivities of about 1 pC/l. The radioactive elements in the rain-water of about 250
ml* were separated by the similar procedure as described in III, 3-a, using ion exchanger. The result is shown in Fig. 30, and the presence of Sr", Ba'10, Nb"S
and Zr'' was ascertained by 13-rayabsorption curves, as shown in Figs. 31, 32 and 33.
Of these nuclides we were able to determine the absolute activity for only Zr'" to
* The rain-water was collectedby Prof. T. Shidei, Department of AppliedPhysics, Kyoto
University.
( 56 )
Radiochemical
Analysis
of the
Bikini
Ashes
1200
1000
NO
V
.,uv7
>-(gt=0.54)
t=
U
Q
\1\I
400•
200
-
0 2 q. 6Sto
12 14 Iro-------------------------------------------22
4CM
Fig. 27 Elution curve of paper chromatograph.
ro*
I
I
I
I
I_
I
(.
I
2k.
1000•
OW
2 is
"u•`
-C,.=5 hiGyt0_oo• U
4Z(0.24
MEV)_2~~/T.=G.63
S—Vso1
t0.IOd•
7 1-Y
FSoo
o5
f6ACKGR0UN0
100
10
20
-
40 SO 60 10 8010DECAY
Al A6S0RSER,
MG/CM0
Fig. 28 Aluminum absorption curve ofFig.
U.
0, original points. za, y
background subtracted.
00
( 57 )
y
• CONTAMINATIONt
.:<
1
29
SO TIME
u.2021
, DAYS
Decay curve of U237.
10
S
M. ISHIBASHI,
S. OKADA,
S. SHIMIZU
et al.
10...'dI
I
I
1
S/T3i=78MG/CM7—
RAEARTMBu2/(I.5
P•1d//J
s
MEV)—
101.}-o=
y.a
1-'A2.10225
Fu
5—
-—
RADID•5
COLLAID5U
1=Sr
u
,r
'010
ea30
Fig. 31
Jof
..58ISCI0.555'5°,
57e
MMALIC
CITRATE
CITRATE
ACIDPH3.50 PII5.40
10-I1II11I
0
100200300400600600100
60
40120
2 150
AI ABSORBER, MG/CM
Aluminum absorption curve
Srss in the rain-water.
VOLUME
OF ELUATE.,ML
Fig. 30
Group separation of the radioactive
elements in the rain-water
(Kyoto
City, May 16, 1954) by an ion exchanger : Amberlite IR-120 (100,—
150 mesh) ; bed dimension 20 cm x
0.28 cm2; flow rate 0.2 m1/min/cm2
I
l
I
1
=
s—
I
I
I
I
II
I1——
1——
02—
E:
=39MG/CM2_
5—/
(1.07MEV)_~,:
-/(0.4
MEV)—
—
}~ 1—~s—Ty2=
f1
—
—
2.5MG/CM2—
_(us'mEv)
sQ
F Ip=—
u 4 _-
2,—
Ics——
5—.—
2——
I
I
I
II
I
10J2040
----------------------------------------------------------------------------------------------------------------------------I
I
I
I10
5Al505 ABSORBER
60>;0
100120
,30MG
CMi 30
Al ABSORBER,
MG/CM'Fig
Fig. 32Aluminum
absorption curve ofZr°5
Bailo in the rain-water.O,
.33 Aluminumabsorptioncurveof
and Nb°> in the rain-water.
Zr". n, Nb95.
( 58 )
Radiochemical Analysis of the Bikini Ashes
be 5.7 x 10
counting
/LC ± . 20% per liter, taking many
factors
concerning
the
absolute
/9
into consideration.
V. SUMMARY
From the Bikini
Ashes following nuclides
were
assigned
by
the radiochemical
procedure ; Ca45 Sr" Ye ZrJS Nb05 Ru'-0' Rh103' Rum', Rh:oh Te"'
I's' Baiao
La'40, Ce1", Pr"' and 1J2:;7. The ion exchange method was very effective for the
analysis
of rain-water,
ascertained,
from
which
the
presence
while the presence of rare earths was
could not be carried
Comparing
of Sr",
Zr95, Nb°J and Ba"°
also found but their
was
assignments
out.
the elution curves
on May 16 (Fig. 30), obtained
for the Bikini Ashes (Fig. 19) and the rain-water
by the similar procedure,
one can find at once that the
peaks in the curves corresponding to each species differ considerably,
especially for
anions and alkali earths. From these results it seems probable that the radioactivities
in the rain-water
have
been
caused by the nuclear
detonation
which
might
take
place a few weeks before. However, this estimation
should be ascertained
by the
absolute measurement of activities for each nuclides, which, to our regret, could not
be carried
absolute
out owing to insufficient
data concerning
several factors necessary
for the
measurement.
VI. ACKNOWLEDGEMENT
The
Education
authors
are very fortunate
for the special research
to express their gratitude
to the Ministry
of
grant.
REFERENCES
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
K. Way and E. P. Z. Wigner, Phys. Rev. 73, 1318 (1948).
H. F. Hunter and N. E. Ballou, Nucleonics, 9, No. 5, C-2 (1951).
L. Melmander and M. Slatis, Phys. Rev. 74, 709 .(1948).
D.W. Engelkemeir et al, Phys. Rev. 72, 967 (1947).
M. Ishibashi, "Laboratory Directions in Quantitative Analysis", Fuzambo, Tokyo (1952):
(In Japanese).
F. P. Treadwell, and W. T. Hall, "Analytical Chemistry," Vol. I, 8th English Ed.,
p.542, p. 545.
B. H. Ketelle and G. E. Boyd, J. Am. Chem. Soc., 69, 2800 (1947).
W. R. Scholler, Analyst, 69, 259 (1944).
C. D. Coryell and N. Sugarman, "Radiochemical Studies; The Fission Products," Book
3, p.1914, McGraw-Hill Book Co. Inc., New York, (1951).
C. D. Coryell and N. Sugarman, ibid., p.1654.
( 59 )