Model-based Design Evaluation of a Compact, High-Efficiency Neutron Scatter Camera

Abstract

This paper presents the model-based design and evaluation of an instrument that estimates incident neutron direction using the kinematics of neutron scattering by hydrogen-1 nuclei in an organic scintillator. The instrument design uses a single, nearly contiguous volume of organic scintillator that is internally subdivided only as necessary to create optically isolated pillars. Scintillation light emitted in a given pillar is confined to that pillar by a combination of total internal reflection and a specular reflector applied to the four sides of the pillar transverse to its long axis. The scintillation light is collected at each end of the pillar using a photodetector. In this optically segmented design, the (x, y) position of scintillation light emission (where the x and y coordinates are transverse to the long axis of the pillars) is estimated as the pillar's (x, y) position in the scintillator "block", and the z-position (the position along the pillar's long axis) is estimated from the amplitude and relative timing of the signals produced by the photodetectors at each end of the pillar. For proton recoils greater than 1 MeV, we show that the (x, y, z)-position of neutron-proton scattering can be estimated with < 1 cm root-mean-squared [RMS] error and the proton recoil energy can be estimated with < 50 keV RMS error by fitting the photodetectors' response time history to models of optical photon transport within the scintillator pillars. Finally, we evaluate several alternative designs of this proposed single-volume scatter camera made of pillars of plastic scintillator (SVSC-PiPS), studying the effect of pillar dimensions, scintillator material, and photodetector response vs. time. Specifically, we conclude that an SVSC-PiPS constructed using EJ-204 and an MCP-PM will produce the most precise estimates of incident neutron direction and energy.

References in corpus (1)

• A High-resolution Scintillating Fiber Tracker With Silicon Photomultiplier Array Readout

Cited by in corpus (7)

• Proton Light Yield in Organic Scintillators using a Double Time-of-Flight Technique
• Low Energy Light Yield of Fast Plastic Scintillators
• Interaction position, time, and energy resolution in organic scintillator bars with dual-ended readout
• Proton light yield of fast plastic scintillators for neutron imaging
• Simultaneous measurement of organic scintillator response to carbon and proton recoils
• Neutron Response of the EJ-254 Boron-Loaded Plastic Scintillator
• Efficiency Studies of Fast Neutron Tracking using MCNP