Film badges
In September 1959,
film badges sealed against moisture were q
exposed at Rongelap and Kabelle islets to measure gamma doses in
different areas.
.
The badges were provided and set out by Radi-
ation Safety personnel at the Pacific Proving Ground.
of detection was an accumulated dose of 10 mr.
placed at each location,
The limit
Three badges were 4
one suspended by strings three feet
above the ground and away from tree trunks,
the ground attached to a tree,
one three feet above 4
ty
and one on the ground.
Gamma dose 4
ag
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
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
of measurement,
absolute values depend on calibration with
6
a
1