A large-area scintillation neutron detector based on WLSF and SiPM readout

Position-sensitive neutron detectors play an important role in neutron scattering studies. Detectors based on ⁶LiF/ZnS (Ag) scintillator and wave-shifting fiber have the advantages of high neutron detection efficiency, high position resolution, and large-area splicing, and can well meet the requirement of large area neutron detection for neutron diffractometers. An engineering detector prototype based on a ⁶LiF/ZnS (Ag) scintillation screen and SiPM array readout was fabricated for the General Purpose Powder Diffractometer of China Spallation Neutron Source (CSNS). The detector has an active area of 196 mm × 444 mm, with a pixel size of 4 mm × 4 mm. The key performances of the detector prototype were tested at the BL20 neutron beam line of CSNS. The test results show that the neutron detection efficiency of the detector was 32% and 42% at wavelengths of 1.4 Å and 2.8 Å, respectively. An interpolated neutron detection efficiency of 40.2% at a wavelength of 2 Å was obtained. The tested neutron efficiency non-uniformity of the detector was 10.2%, which is less than one-half that of the current general purpose powder diffractometer scintillator neutron detectors at CSNS. This work achieves, for the first time, an efficiency uniformity of < 11% in large-area mosaic neutron detectors, alongside significant advancements in electromagnetic interference immunity and cost-effectiveness.