Commissioning a time-gated camera for fast neutron beamline spatial-energy characterization at LANSCE-WNR spallation source

Journal Article · 23 November 2024 · Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment

DOI: https://doi.org/10.1016/j.nima.2024.170088 · OSTI ID:2500897

Broughton, David Paul  ^[1]; Svoboda, Josef  ^[1]; Kuvin, Sean Andrew  ^[1]; Lee, Hye Young  ^[1]; Mocko, Michael Jeffrey  ^[1]; DiGiovine, Brad Joseph  ^[1]; Mosby, Shea Morgan  ^[1]

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1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

An energy-resolved fast neutron beam imaging diagnostic has been successfully commissioned at the Weapons Neutron Research (WNR) spallation source within the Los Alamos Neutron Science Center (LANSCE) facility. This diagnostic replaces the existing analog phosphor image plates, which integrate across all neutron energies, as well as other particles, with a near-real-time energy-sensitive imaging capability. The system uses a fast plastic scintillator coupled with an intensified CCD camera. Specifically, the Teledyne Pi-MAX4 camera is coupled with either a 4 mm thick Eljen (EJ) 204 or 228 plastic scintillator. These scintillators are most sensitive to the fast neutrons (0.8-800 MeV) directly from the spallation source rather than low energy background radiation. Experimentally, these plastic scintillators were shown to have sufficiently fast decay to differentiate the bright gamma flash from the spallation neutrons. The spatial resolution is dominated by neutron beam divergence, with minimal additional contributions from scatter and light divergence. The system successfully resolved changes in neutron beam characteristics caused by intentional proton steering variations. Additionally, simulations of scintillator light yield as a function of thickness conducted using PHITS (with Scinful-QMD package) found that increasing scintillator thickness from 4 mm to 6 or 8 mm could potentially increase brightness ~ 3x. This may be explored if there is a need to reduce image acquisition time from several minutes to under one minute.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE; USDOE Laboratory Directed Research and Development (LDRD) Program
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 2500897
• Report Number(s): LA-UR--24-28493
• Journal Information: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Journal Name: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment Vol. 1071; ISSN 0168-9002
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English