Calibration of a Radiation Detector: Chromosome Dosimetry for Neutrons

Abstract

Calibrative densities for the unknown neutron dose D_f of an individual accidentally exposed to high doses (>20 rad) of neutrons are derived. These densities incorporate prior dose information (e.g., from a dosimeter reading, or from dose reconstruction efforts), information from an in vitro calibration experiment with neutrons of the same energy, and information from the number of dicentric chromosome aberrations y_f observed shortly (< 4 weeks) after exposure in a sample of n_f lymphocytes from the exposed individual. If Y, the number of dicentric aberrations induced by a known neutron dose d in n lymphocytes is assumed to be Poisson distributed (Y ~ Po(nαd)) and if D_f and the parameter α are assumed to have gamma priors it is possible to give an analytic solution for the calibrative density f(d_f|D). D consists of the calibration data and the observed aberrations in a sample of lymphocytes from the exposed individual. This density characterizes the remaining uncertainty about D_f after consideration of the prior information about D_f and α and of the data D.