Calibration of a Radiation Detector: Chromosome Dosimetry for Neutrons

Calibrative densities for the unknown neutron dose Df 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 yf observed shortly (< 4 weeks) after exposure in a sample of nf 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 Df and the parameter α are assumed to have gamma priors it is possible to give an analytic solution for the calibrative density f(df|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 Df after consideration of the prior information about Df and α and of the data D.