Pulse-Shape Discrimination of 3-in Size NaI:Tl,⁶Li Scintillator Coupled With SiPM Array

Abstract

Single crystals of NaI:Tl,6Li, a newly developed neutron-gamma scintillator, have satisfactory <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n/\gamma $ </tex-math></inline-formula> discrimination capability and ease of scaling up. Using a silicon photomultiplier (SiPM) instead of a photomultiplier tube (PMT) as a readout for detector miniaturization has attracted considerable attention. Herein, we systematically compare the gamma spectroscopy and n/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\gamma $ </tex-math></inline-formula> discrimination performance of a 3-in NaI:Tl,6Li single crystal using R6233-100 PMT and two types of SiPM arrays as readouts. Using the PMT as a readout, a satisfactory energy resolution of 8.6% at 662 keV and an excellent figure of merit (FoM) of 4.36 at 1-GHz sampling rate can be achieved. Using the two types of SiPM arrays as readouts, the detectors have good linearity with energy resolutions of 14.4% and 10.6% at 662 keV and FoM values greater than 3- at 1-GHz sampling rate. Notably, at low sampling rates, the detector based on a 3-in NaI:Tl,6Li single crystal and SiPM array can maintain a very beneficial pulse-shape discrimination (PSD) performance, such as an FoM value of up to 2.73 at a sampling rate of 20 MHz.