The response of xenon X-ray detectors to full-energy absorption and fluorescence-escape events: measurement and modelling

We have observed that the pulse-height distributions of X-ray events that deposit essentially the same amount of energy in a xenon gas detector will vary according to the deexcitation pathways available to the photoionized atoms. A xenon gas proportional scintillation counter was used to compare the pulse-height distributions of events in which fluorescence X-rays from xenon escape detection. Experimental results are presented and the behaviour for different types of events is clarified using Monte Carlo simulation. The results indicate that particular care must be taken when using escape peaks for energy calibration of xenon gas detectors.