Cold neutron imaging and efficiency measurements with a Boron-10 coated double-GEM detector

A 10 B -coated cathode double-GEM neutron detector (BGEM) was developed as a 3 He -free cold-neutron beamline detector using a single B 4C converter cathode and a 512-channel APV25 orthogonal-strip readout over 10 × 10 cm 2 . The detector was tested at the HANARO Bio-REF beamline with a monochromatic 4.5 Å beam ( E n = 4.03 m e V ). The detection efficiency relative to a 6 Li -based Ce:LiCAF reference detector was ɛ ɛ BGEM = ( 8.69 ± 0.20 ) % (stat.) . The pulse-height spectrum was qualitatively consistent with Geant4 energy-deposition simulations, and Cd-mask imaging yielded σ = ( 555 ⊕ 102 ) μ m , corresponding to FWHM LSF = ( 1.31 ⊕ 0.24 ) mm . These results establish a cold-neutron beamline benchmark for a single-converter BGEM detector with full-strip APV25 readout.