Non-linearity effects in the response of cadmium telluride nuclear radiation detectors

An investigation has been made of the count-rate response of several CdTe detectors, to dose-rates in the range 0.1 Rad/h to 80 Rad/h. The relationship was found to be non-linear and it is suggested that this is due to a reduction in the depletion layer thickness resulting from the trapping of charge carriers. Over a limited range of dose-rates the relationship is of the form C = KDsup(n), with a mean value of n of 0.77 +- 0.03. This value is consistent with the limits of n of 0.67 and 1, predicted by a model proposed for the reduction in depletion layer thickness. Radiation induced polarization was also observed but is thought not to be the cause of the non-linear response. (Auth.)