Development of energy-resolved neutron imaging detectors at RADEN

TL;DR

This paper discusses the development and enhancement of energy-resolved neutron imaging detectors at RADEN, focusing on improved spatial resolution, detection efficiency, and count rate capabilities using micro-pattern detectors and scintillators.

Contribution

The paper presents advancements in micro-pattern neutron detectors, including improved spatial resolution, efficiency, and rate performance at the RADEN instrument.

Findings

Spatial resolution improved from 200 to 100 μm.

Detection efficiency increased from 18% to 26%.

Maximum count rate increased from 0.4 to 1 Mcps.

Abstract

Energy-resolved neutron imaging at a pulsed source utilizes the energy-dependent neutron transmission measured via time-of-flight to extract quantitative information about the internal microstructure of an object. At the RADEN instrument at J-PARC in Japan, we use cutting-edge detectors employing micro-pattern detectors or fast Li-glass scintillators and fast, all-digital data acquisition to perform such measurements, while continuing their development toward better utilization of the intense neutron source. In particular, for the Micro-Pixel Chamber based Neutron Imaging Detector ({\mu}NID), a micro-pattern detector with a 400 {\mu}m pitch and employing 3He for neutron conversion, we have successfully improved the spatial resolution from 200 to 100 {\mu}m, increased the detection efficiency from 18 to 26% for thermal neutrons, and increased the maximum count rate from 0.4 to 1 Mcps. We are also testing a new readout element with a 215 {\mu}m pitch for further improved spatial resolution, and a {\mu}NID with boron-based neutron converter for increased rate performance.