Development of Two-Dimensional Neutron Imager with a Sandwich Configuration

TL;DR

This paper presents the development and testing of a novel two-dimensional neutron imager with a sandwich sensor configuration, aimed at quantum gravity experiments involving ultra-cold neutrons.

Contribution

It introduces a new sandwich-configured semiconductor pixelated sensor for neutron imaging and demonstrates its effective response to ultra-cold neutrons at a major research facility.

Findings

Achieved about 16% detection efficiency relative to a reference detector.

Successfully observed simultaneous events on both sandwich sensors.

Coincidence detection reduces efficiency by approximately a factor of 3.

Abstract

We have developed a two-dimensional neutron imager based on a semiconductor pixelated sensor, especially designed for experiments measuring of a spatial and a temporal behavior of quantum bound states of ultra-cold neutrons. Through these measurements, we expect to measure the ratio between the inertial and gravitational masses of neutrons and to test the equivalence principle in the quantum regime. As one of the principal neutron imagers, we fabricated a sensor with a sandwich configuration, named 10B-INTPIX4-sw, and tested its response to ultra-cold neutrons at the Los Alamos Neutron Science Center (LANSCE). We observed simultaneous events on both sandwiching sensors without significant loss of detection efficiency. The efficiency was evaluated to be about 16%, relative to the 10B/ZnS reference detector. The coincidence condition reduces its efficiency by a factor of about 3.