An improved model for ultraviolet- and x-ray-induced electron emission from CsI

A microscopic theoretical model is proposed for calculating the characteris tics of ultraviolet photoemission and x-ray secondary electron emission ind uced from CsI photoconverters. This approach is based on a realistic pictur e of the basic interactions of photons and induced electrons within the mat erial. Both differential and integral emission characteristics, such as ene rgy spectra and quantum efficiencies, are estimated according to the model and are found to agree, in general, with experimental data. The model-calcu lated photoemission enhancement under high external electric fields is also considered and is fairly compatible with measured values. The applicabilit y of the model in the field of radiation detectors incorporating solid phot oconverters is discussed. (C) 1999 American Institute of Physics. [S0021-89 79(99)07422-8].