Digital signal processing for a thermal neutron detector using ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs

Abstract

We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag): 6 LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC 4 filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC 4 filter has been emulated digitally. The detector performance obtained with this analog approach is compared with the one obtained with the best performing digital approach.

Selection of silicon photomultipliers for a6LiF:ZnS(Ag) scintillator based cold neutron detector

“…The appealing properties of the SiPM, principally low cost, radiation hardness [16,17], insensitivity to magnetic fields, and compact size make it of particular interest for our application. Other researchers have employed them in neutron detection applications as well [8,18,19]. Advances in the design of these devices have resulted in improvements in photon detection efficiency (PDE) from 20% to 30% and a reduction of the dark noise rate from 1 MHz events per mm 2 to less than 30 kHz per mm 2 .…”

A 16-ch module for thermal neutron detection using ZnS:6LiF scintillator with embedded WLS fibers coupled to SiPMs and its dedicated readout electronics

“…This signal is sampled every 400 ns by measuring the number of SD-pulses during each consecutive time slice of 400 ns. In [10], the performances of the detector obtained with several digital filters are compared. The best evaluated filter, the so-called "moving sum after differentiation" (DI+MS) filter, is the one which has been implemented in the WaveDREAM board.…”

“…The detection module is operated with the following settings of the signal processing: M=5, blocking time = 4 µs, threshold = 20 SD-pulses. With this settings and up to a SiPM dark count rate of 4 MHz, the performance parameters of the detection module reported in [10] are: trigger efficiency = 81%, background rate < 10 −3 Hz/ch, probability of multiple trigger < 10 −3 , time resolution (StDev) < 170 ns (contribution from the signal processing). Based on recent measurements performed with an analog CR-RC 4 filter, which is equivalent to the DI+MS filter, we estimate the gamma sensitivity of the detection module to 10 −7 up to a SiPM dark count rate of 4 MHz.…”

Silicon photomultiplier based scintillator thermal neutron detector for China Spallation Neutron Source (CSNS)

“…In recent years, SiPMs have attracted increasing attention owing to their high single-photon resolution, ease of integration, and low operating voltage. [12][13][14] In this work, to achieve excellent detector performance such as low cost, small dead area, and good uniformity of detection efficiency, the SiPM is used instead of the MA-PMT for photoelectric conversion. A self-designed ASIC electronics has also been developed for the new detector system.…”