with a
Total r-radiation in Seaw iter Measured
er
count
cintillation
* Masaharu OKANO
s A scintillation counter was used to monitor radio-
vecontamination of sea water by 7 emitting nuclides.
l.
Ablock diagram of the counter is shown in Pig,
A
sodium iodide crystal, 15" in diameter and 1s" long, was
The construction of the
| used. as the phosphor element.
scintillation probe is the same as the type used in the
radiological survey performed by the "Shunkotsu Maru"
| during 1956
However,
the circuitry of the electronic
equipment used during this survey trip, was completely
transis torized.
th a The length of the scintillation probe cable was
300m enabling measurements at a depth of 20Um.
The
| true depth was made by the readings on the bathythermo graphs,
| The + counting rates at each station are shown in Table l.
In;;these values, the discrimination level of the measuring
0
Oror
| 1°08.8'N 165°09.0'W
1°55. O'S 165° OO.
18
GW2RO Aug 62
Ham
16
|
19 Aug 62
29k
133
233
0
148
device was set at approximately 70 keV of the electron
energy walue in the phosphor clement. At some stations
ray spectrum was measured with the scintillation
combined with an RCL 128 channel pulse height
rt
oR
titute of Physical and Chemical Research
0
<
Scintillation Counter Block Diagram
6
a
E
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2{tO
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7
(RCA 6199)
Pre-amplifier
[Counting
#Amplifier|Scaler
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1
cd
d
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