CAPABILITIES OF THE PERSONNEL MONITORING BADGE IN JAERI

For the purpose of personnel monitoring for external radiations in JAERI, where mixed radiation fields of gamma rays, BETA rays, and neutrons are usually encountered, special badge meters have been developed since 1958. A table shows the type of these badges and their constructions. In this report, the capabiiities of the newest badge are shown by measuring the true dose absorbed by the body from experimental data. The photon energy response was neariy constant (within a variation of plus or minus 20%) between 260 kev and 10 Mev. The effects of directional dependence of the gamma radiation were negligible above 206 kev, but became quite large as the energies decreased. The latent image stability of gamma -ray film was less than 10% during 4 months in the air-conditioned room, but that of Kodak P.N.M. filna for fast neutrons deteriorated as much as 90% in one month. The latter was improved to 20% in one month by wrapping the film with Krewrap'' and using an airtight badge. The method of differential measurements of mixed radiation fieids is presented. Especially for gamma rays, the relation between badge response and tissue dose is discussed, considering the effects of directional dependence of the badgemore » and back-scattered radiations from the body. (JAIF)« less