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Y-793 - CALIBRATION OF A FLOW-TYPE IONIZATION CHAMBER WITH RADIOACTIVE
SULFUR DIOXIDE.
J. W. Thomas and R. L. Quinn, 20 August 1951.
UNCLASSIFIED
_
(Uv)
An ionization chamber equipped with a vibrating-reed
electrometer and recorder was calibrated for continuously measuring
» radioactive sulfur dioxide in a flowing gas stream.
The calibration was
pa ea Ms
made by counting the 539 after conversion of gas samples to BaS390k.
A calibration factor of 0.64 x 10711 amp of ion current/yc/liter of
$370 was established. The detectable limit was calculated to be 1.5 X 10°
:
4
pe/liter.
By using a collecting potential of 2,000 v, activities up to at
least 3 me/liter may be measured.
At high voltages the ion current is
2
proportional to the gas activity, no difference in ion current being noted
™
when gas flowed through the chamber at 32 liter/min and when there was no
gas flow.
ORNL - 1378
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-
GAS MASK CANISTER TESTS AGAINST RADIOACTIVE SULFUR DIOXIDE.
Jess W. Thomas, 2 September 1952.
:
SECRET-RESTRICTED DATA
This report describes the development of an ultrasensitive method
of gas-mask canister testing wherein a radioactive gas, 830s,
rather than a nonradioactive medium.
is used
Use of a radioactive test-medium
makes possible readings of high sensitivity, and also permits the use of
continuous-recording instruments for gas concentration determinations.
5
was selected as the test nuclide because it is a pure beta-emitter, so that
shielding problems are negligible, and because its half-life of 87 days
entails no serious, long-term decontamination problem.
Payee “ Mee
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The test apparatus and procedures are described.
Penetrations
as low as 1073 mmg /liter could be estimated.
The results indicate that
the M11 canister has an efficiency greater than 99.98% against radioactive
REST
70
pat
.
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sulfur dioxide, (1 mc/liter) for the first 20 min of test.
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