Performance and pulse shape discrimination of glass scintillator SG101 for neutron detection

TL;DR

This work evaluates the thermal-neutron–sensitive SG101 glass scintillator, benchmarked against EJ426 under AmBe irradiation, and explores its performance in composite detectors with EJ200 and EJ276. SG101 demonstrates superior neutron detection efficiency, narrower and more stable signal distributions, and strong PSD capabilities, achieving a maximum FOM of 3.81 for thermal-neutron/gamma discrimination (SG101+EJ200) and clear multi-population separation (gamma, fast neutrons, thermal neutrons) for SG101+EJ276 with <5σ separation. Energy linearity is validated across 0.3–1.1 MeV for both SG101+EJ200 and SG101+EJ276, with p.e./MeV scales of approximately 495.7 and 673.1, respectively. Coincidence analyses reveal significant genuine fast–thermal correlations within 100 μs (τ ≈ 11.3 μs) and meaningful triple-coincidence signals, indicating practical utility in time-correlated neutron detection and background-suppressed neutrino–detection schemes.

Abstract

We present a detailed characterization of the thermal neutron sensitive transparent glass scintillator SG101, benchmarked against the conventional LiF ZnS(Ag)based scintillator EJ426. The detection efficiency, energy resolution, and pulse shape discrimination (PSD) performance ofSG101 were evaluated under AmBe neutron irradiation. When coupled with organic scintillators(EJ200 or EJ276),the SG101 EJ200 system achieves a figure of merit (FOM) of 3.81 for thermal neutron/gamma separation, while the SG101 EJ276 configuration resolves three distinct particle populations gamma rays, fast neutrons, and thermal neutrons with FOM values of 3.46 and2.21, respectively. Correlation analysis reveals that the number of fast thermal neutron coincidence events significantly exceeds the accidental background, and the count of gamma fast thermal neutron triple-coincidence events is also far higher than the expected accidental rate, confirming significant physical correlations for both event types within a 100 us time window. These results demonstrate that SG101 is a promising candidate for applications requiring high-efficiency thermal neutron detection and precise event tagging coupling with a scintillator with PSD approach

Figures (10)

• Figure 1: Upper panel: Schematic of the experimental setup. The scintillator is optically coupled with silicone grease to a PMT on one end and to SG101 on the other end, all enclosed in a light-tightness box. The lead and HDPE bricks provide $\gamma$ and neutron shielding, respectively. Variable-thickness HDPE layers between SG101 and the neutron source enable neutron moderation. Data are acquired using either an oscilloscope or a CAEN DT5751 digitizer as needed. Lower panel: Photograph of the detector assembly.
• Figure 2: The left panel shows the EJ276 plastic scintillator,which has the same dimensions with EJ200.The central panel displays the EJ426 scintillator, while the right panel presents the SG101 scintillator.
• Figure 3: Left panel:A single-pulse waveform sample from SG101 scintillator. Right panel:A single-pulse waveform sample from EJ426 scintillator which has many spikes in its falling edge compared with SG101 waveform.
• Figure 4: Left panel: 2D histogram of signal integral versus PSD values obtained using the SG101 detector; Right panel: corresponding distribution using the EJ426 detector. These figures are used to visually compare the differences in signal integral and PSD characteristics between the two different detector materials.
• Figure 5: Left: Linear fit results using data from the EJ200 + SG101 detector combination. Right: Gaussian fits to the Compton edge energies of 137Cs (0.477MeV), 22Na (0.341MeV and 1.061MeV), and 60Co (0.9632MeV and 1.1182MeV). Given that the two 60Co peaks are too close for accurate double-Gaussian fitting; therefore, their average value was used. The left figure shows a linear fit based on the mean and standard deviation values from the Gaussian fits, converted into photoelectron numbers.