Pile-Up Real Time Pulse-Shape Discrimination Based on Ballistic Deficit Measurement and Digital Time-Invariant Pulse Shaping

摘要

A simple yet robust algorithm to analyze and discriminate pulse shapes from radiation detectors capable of pulse-shape discrimination (PSD) is presented. This algorithm is implemented in real time and does not require storage of digitized data and off-line signal processing. The signal from the radiation detector is first integrated by an RC amplifier with a relatively short time constant. The integrated signal is sampled at 125MHz by a 16-bit ADC. Two digital pulse shapes are synthesized in real time by a time-invariant digital pulse processing system. The first pulse shape is trapezoidal and the second is an inverse sawtooth pulse shape. The pulse-shape analysis is performed by a simple pulse-height measurement of both pulse shapes. This PSD method does not require and does not depend on detector event timing information, as the digital pulse shapers are time invariant and all PSD information is derived by pulse-height measurements only. It is not critical to synchronize the ADC sampling clock with the time of arrival of the detector events.