Preliminary Study of the Louver structure scintillator neutron detector with SiPM readout

Abstract The China Spallation Neutron Source (CSNS) is a large-scale scientific facility dedicated to investigating the microscopic structure and dynamic behavior of materials using high-intensity neutron beams. Among the neutron spectrometers currently under construction at CSNS, the Energy-Resolved Neutron Imaging Spectrometer (ERNI) imposes rigorous physical requirements on the detectors positioned at its 90 ∘ diffraction angle, including high neutron detection efficiency and superior spatial resolution. To address these challenges, this work introduces a novel scintillator-based neutron detector featuring an oblique-incidence louvered structure in its detector head. This design enhances neutron capture efficiency by optimizing geometric acceptance, while a silicon photomultiplier (SiPM) array is employed for optical readout. The centroid method is further applied to achieve spatial resolution surpassing the physical dimensions of individual SiPM pixels. A prototype detector with an active area of 102.0 mm× 81.4 mm was developed and evaluated on CSNS neutron beamlines to systematically characterize its core performance metrics, including spatial resolution and detection efficiency. Beamline test results demonstrate that the detector achieves 1.0 mm spatial resolution in the X-direction and 3.4 mm resolution in the Y-direction,witha 54.2% detection efficiency for 1.0 Å neutrons. These performance parameters align robustly with the physical demands of ERNI for single-crystal diffraction measurements, validating the detector's design and operational efficacy.