Film badges In September 1959, film badges sealed against moisture were 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. 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 and one on the ground. feet above 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 of measurement, absolute values depend on calibration with 6 /o