Photoelectron collection efficiency at high pressure for a gamma detector envisaging medical imaging

Abstract

Recent developments on gas avalanche detectors based on microstructures operating at high pressure allow fair detection efficiency for hard X- and gamma-rays. A hybrid system combining an assisted scintillation in a highpressure xenon gas medium and two UV photosensors based on microstructures operating face to face, having the xenon medium sandwiched between, is under investigation for imaging purposes. To evaluate the photosensor operation at high pressure, a study of the photoelectron collection efficiency (PCE) is needed. First results show no significant variation on the relative PCE from 1 to 5 bar xenon filling pressure for different applied voltages.