i ee
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In September 1959,
film badges sealed against moisture were
exposed at Rongelap and Kabelle islets to measure gamma doses in
The badges were provided and set out by Radi-
tyes
- Gifferent areas.
ation Safety personnel at the Pacific Proving Ground.
A
eoBE ae BeaseRa
Film badges
of detection was an accumulated dose of 10 mr.
The Limit
Three badges were
placed at each location, one suspended by strings three feet
above the ground and away from tree trunks,
the ground attached to a tree,
one three feet above
and one on the ground.
Gamma dose
rates measured with a survey meter at each location indicated
that the accumulated dose in 69 out of 116 film badges would be
in excess of 10 mr, but less than 20 mr.
however, negative for all badges.
The results were,
The discrepancy between the
doses calculated from the survey meter measurements and those
obtained with film badges may be explained by differences in
sensitivity of the two methods to the gamma energies present in
the field.
Calibration was based on a radium standard rather
than on actual fallout material.
This discrepancy does not
invalidate the decline curves in Figs. 2 and 3 since the theoretical curve
(solid line)
is based on measurements with a survey
meter similar to those used for the various measurements made.
_ However, the discrepancy does point out that while relative
levels of activity can be determined accurately by any one type
a
7
1
jakenena
ibration with
depend on cal
Department of Energy
of measurement, absolute values
6
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