Calibration of shadow shield whole body radioactivity monitors with a single radionuclide source

Whole body counting of occupational workers at the nuclear facilities is a recommended monitoring procedure for assessment of internal depositions of gamma emitting radionuclides. Thirteen shadow shield whole body radioactivity monitors, designed, developed, supplied and commissioned by BARC are presently operating at various nuclear installations in India, to serve this purpose. For calibration of these monitors a standardised phantom made up of ten water filled plastic containers and a set of ten sources of a radionuclide, each of strength proportional to the weight of a particular phantom block, are used to simulate a uniform distribution in human body. Concepts, calibration procedure and results for this single source method are discussed