Pulse response of GaAs and InP photoconductive detectors for the X-ray diagnostics of laser plasmas

Bulk and surface-oriented GaAs and InP photoconductive detectors were fabricated for the detection of X-ray pulses from laser plasmas. Current–voltage curves, pulses from different lasers as well as pulse-height spectra measurements using light pulses are used to compare the detectors. Non-linear dependence of the response on excitation intensity is found and investigated in detail. The results are explained by carrier trapping/detrapping and recombination phenomena. The response to X-ray pulses from a picosecond laser plasma are presented as well. InP detectors were of higher performance.