Development of a wavelength-shifting-fibre-based scintillator neutron detector as an alternative to He at J-PARC/MLF

Nakamura, Tatsuya  ; To, Kentaro  ; Honda, Katsunori; Birumachi, Atsushi; Ebine, Masumi ; Sakasai, Kaoru  ; Soyama, Kazuhiko  ; Katagiri, Masaki*

A wavelength-shifting fiber based scintillator detector has been developed as a helium-3 alternative detector in J-PARC/MLF. The detector is aimed at using for an inelastic neutron scattering instrument in a pulsed neutron source. The detector should have a capability to have a large-area coverage with a moderate pixel size as well as high detector efficiency, low sensitivity, and a low background rate. We have developed a detector that has a larger neutron-sensitive area with a moderate pixel size based on the detector implemented in the SENJU instrument in the J-PARC/MLF. The prototype detector has a pixel size of 20 20 mm with a neutron-sensitive area of 320 320 mm. In the presentation detailed detector performances are presented in comparison to those measured by an original SENJU detector.