A Novel Method to Improve the Spatial Resolution of GEM Neutron Detectors With a Stopping Layer

Abstract

The gas electron multiplier (GEM) detector in combination with a solid converter has been widely used in the field of neutron detection in recent decades. Typically, the submillimeter is an important indicator for neutron detectors to satisfy many applications requiring a high spatial resolution. This article proposes a novel method to improve the spatial resolution of ceramic GEM detectors by adding a stopping layer on top of the solid <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> C neutron converter. This will restrict the emission of the secondary ion products of large angles and consequently improve the spatial resolution. The Monte Carlo program FLUKA is used to validate the method, and the verification experiments are carried out at beam line #20 (BL20) of the China Spallation Neutron Source (CSNS). The experimental results are approximately in agreement with the simulations. The measured spatial resolution is 1.87 mm for the GEM neutron detector operated at ambient pressure with a 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> -thick <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> C converter and a drift gap of 4 mm, eventually, it is improved to ~0.8 mm by coating a 3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> -thick titanium on top of the <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> C converter.