High speed photon counting processing for CdTe detector

Abstract

Recently practical X-ray measurement systems are demanded energy distinction function. Photon-counting CdTe semiconductor detectors have a high energy resolution in a low count rate condition at room temperature. However, the energy resolution is decreased by pile-up phenomenon in a high count rate condition. In conventional signal processing, processing time estimated X-ray photon energy from the pulse waveform is about tens of microseconds. This time is depended on the pulse decay time. This paper purposes to maintain the high energy resolution by changing the signalprocessing algorithm which derived the pulse rise height of the output waveform from the CdTe detector in a high count rate condition. As a result, the pulse rise time required to estimate the pulse rise height was short about 100ns at incident X-ray energy 60keV. As the result of energy spectrum by using this data, the FWHM of about 11keV (at 60keV) when the count rate of 500kcps. This result show the possibility that the photon counting sensor has application for the high count rate imaging without decrease of the high energy resolution.