Evaluation of detector performances of new thin position-sensitive scintillation detectors for SENJU diffractometer

Nakamura, Tatsuya  ; To, Kentaro  ; Koizumi, Tomokatsu; Kiyanagi, Ryoji  ; Ohara, Takashi   ; Ebine, Masumi ; Sakasai, Kaoru  

A new thin position-sensitive scintillation neutron detectors have been developed to replace present scintillation detectors in SENJU diffractometer at J-PARC MLF. The SENJU diffractometer originally composed of 37 position-sensitive detectors, where each detector has neutron sensitive area of 256 256 mm with a pixel size of 4 4 mm. To renew some original detectors the new detectors have been developed based on ZnS scintillator and wavelength-shifting fibers technology. The developed replacement detectors were designed with a thin thickness of 12 cm, which is 40% of the original detector. The new detectors have also improved detector performances to the original ones in terms of detection efficiency (60% for 2-A neutrons) and count uniformity (5-8%). The produced six detector modules have been implemented to the beamline after checking their detector performances in the lab.