CHARGE COLLECTION AND CHARGE-COLLECTION TIME IN SEMICONDUCTOR PARTICLE DETECTORS

摘要

Charge collection in semiconductor junction and lithium-drifted, charged-particle detectors was investigated. Analytical solutions were obtained for the charge collected as a function of time and for the charge-collection times in terms of a parameter |30 = x0/D, the reduced range of the incident ionizing particle. It is assumed that the stopping power, dE/dx, of the detector is constant, that there is no loss of carriers by trapping or recombination, and that the motilities of the carriers are constant, independent of the field strength. The implications of these simplifying assumptions are discussed. Figures are presented to illustrate the dependence of the pulse shape on the parameter β0, and optimum operating conditions for the detectors are established. The effect on the collection time of the high fields in the ionization column is estimated.