Multilayer ¹⁰B-RPC neutron imaging detector

Abstract

Resistive plate chambers (RPC) lined with 10 B 4 C neutron converters is a promising cost-effective technology for position-sensitive thermal neutron detection capable to outperform 3 He-based detectors in terms of spatial resolution and timing. However, as for the other types of gaseous detectors with a single layer of 10 B 4 C at normal beam incidence, the detection efficiency to thermal neutrons of a single-gap 10 B-RPC is only about 6%. Aiming to overcome this limitation, we introduce a multi-layer 10 B-RPCs detector with a stack of ten double-gap hybrid RPCs. A description of the detector design and the results of its characterization performed at the TREFF neutron beamline at the FRM II neutron facility are presented. The results demonstrate that the detection efficiency exceeds 60% for neutrons with a wavelength of 4.7 Å and the spatial resolution (FWHM) is about 0.25 mm and 0.35 mm in the X and Y direction, respectively.

Simulation-based optimization of a multilayer 10B-RPC thermal neutron detector

“…Operation of a single-gap 10 B-RPC detector prototype with counting rate densities up to 1 kHz/cm 2 without loss of efficiency has been reported in our previous study [4]. One of the approaches foreseen to improve the counting rate capability of the detector is to increase the number of RPCs [1] distributing the detection of neutrons impinging the detector in the same area over multiple RPCs.…”

“…Firstly, for a hybrid RPC, the 10 B 4 C layers are deposited on both sides of a thin aluminium cathode plate. In order to void deformation of the plate, it is preferable to have the same 10 B 4 C layer thickness on both sides so that the integral of the stress generated by both layers on the plate is null. Therefore, in this study the optimization is performed assuming the same thickness of the converter layer on both sides of the cathode.…”

“…One of the approaches foreseen to improve the counting rate capability of the detector is to increase the number of RPCs [1] distributing the detection of neutrons impinging the detector in the same area over multiple RPCs. Recently we have tested a detector prototype with a stack of 20 RPCs, oriented normally to the beam, each having the same thickness of the 10 B 4 C converter layer [10]. The thickness was optimized to maximize the overall detection efficiency.…”

Concept of a fast neutron detector based on 10B-RPCs

“…Recently we have introduced [12] and experimentally validated [13,14] the concept of a 10 B-RPC thermal neutron detector. The sensitivity of the detector to thermal neutrons is provided by 10 B 4 C neutron converters (see e.g.…”

“…The detection efficiency of a single 10 B-RPC to normal incidence thermal neutrons is only about 5% [12], however, detectors composed of a stack of 10 B-RPCs can provide > 50% detection efficiency, as demonstrated in simulations [12] and experimentally [14]. Manufacture of large area 10 B 4 C coatings on aluminium substrate is already a well-established technology.…”