A Judgment and Correction Method of Nuclear Radiation Pulse Pileup Based on High Speed ​​Digital Sampling

Abstract

The invention belongs to the technical field of nuclear radiation detection and nuclear electronics, and relates to a nuclear radiation pulse accumulation signal judging and correcting method based on high-speed digital sampling. The method includes the steps of pulse accumulation judgment and pulse accumulation correction and specifically includes the steps of judging pulse accumulation, conducting differential on signals, judging the accumulation type, correcting pulse accumulation, calculating pulse waveform parameters, conducting cutting and correcting accumulated pulses. Compared with the prior art, the method has the advantages that the digitalization method of pulse accumulation judgment is set up, complex hardware equipment in a traditional spectrometer is abandoned, differential and analysis are conducted on collected output pulses through the digitalization method so that the current changes of the pulses can be formed, the method is simple and clear, the physical meaning is clear, the accumulation type can be accurately judged, the correction of pulse accumulation can be conducted, the use ratio of the signals can be effectively improved, energy resolution losses caused by pulse accumulation can be reduced, and meanwhile the pulse passing rate of a system is improved to the largest extent.

Description

technical field [0001] The invention belongs to the technical fields of nuclear radiation detection and nuclear electronics, and relates to a method for judging and correcting nuclear radiation pulse accumulation signals based on high-speed digital sampling. Background technique [0002] Energy resolution is the main performance index of nuclear radiation spectrometry system. In addition to the inherent energy resolution of the detector, circuit noise, pulse accumulation and ballistic loss are important factors affecting the energy resolution of the system. At high count rates, pulse pile-up becomes the dominant factor. It has been reported in the literature that when the count rate increases above 1-2kHz, the signal baseline shifts gradually, which deteriorates the resolution, and the peak accumulation of the signal causes great changes in the signal amplitude and waveform, which also leads to the deterioration of the resolution. In this case, it is necessary to consider h...

AI Technical Summary

Problems solved by technology

Using the time interval as the method of discriminative stacking, due to the limitation of the resolution of the circuit itself, it cannot be used to distinguish whether two signals that are very close to each other are stacked or not.

After the time discrimination method, the amplitude rejection method was developed to discriminate the accumulation of signals that are very close to each other. Using this method to distinguish the accumulation of signals, the accumulation of signals with a pulse interval of about tens of nanoseconds can be identified, but for Nearly completely coincident signals are still undistinguishable

Moreover, the amplitude rejection method is only suitable for the measurement of a single energy ray, not for the case where the measurement object has multiple energy ray

In short, the traditional method cannot judge the accumulation at the leading edge and the accumulation at the trailing edge of less than tens of nanoseconds, and in the traditional analog spectrometer, the circuit used for judging the accumulation of pulses is complicated, and the dead time of the system is increased while suppressing the accumulation of pulses.

[0004] In recent years, some scholars in China have adopted the method of simulating the traditional nuclear spectrometer circuit to realize the function of pulse pileup rejection. For example, Chen Shiguo (2006) identified and corrected the pulse pileup after Gaussian shaping. This method is only for Gaussian shaping and is not universal. Qiang; Di Yuming (2008) et al. used curve fitting to identify pulse accumulation, which is complex in calculation and not practical; Zhang Huaiqiang (2012) compared pulse accumulation identification methods with time, but this method is rough and only Judgment based on empirical values; and the above methods all belong to simple discarding of accumulation pulses

Images