Enhanced digital spectrometry of gas proportional scintillation counter pulses in X-ray fluorescence applications

Pulse integration times of several microseconds are necessary to reduce the ballistic deficit in the signals from a gas proportional scintillation counter. However, shorter integration times are desirable when risetime discrimination is applied. To meet both requirements, the pulse is first integrated in the main amplifier with a short (0.1 /spl mu/s) integration time constant for risetime discrimination, followed by digital integration with a longer time constant. When applied to the pulse-height distribution of X-rays from a /sup 109/Cd source, this processing method improves the resolution and the peak-to-background ratio from 5.2% and 17, respectively, for the case of a 5 /spl mu/s analog integration time constant and no risetime discrimination, to 4.4% and 93, when a 0.1-/spl mu/s analog time constant and risetime discrimination and digital integration are applied. In the latter case, 92% of the peak-counting efficiency is retained.