A Two-dimensional scintillation neutron detector module for a new protein single crystal neutron diffractometer at J-PARC MLF

Nakamura, Tatsuya  ; To, Kentaro  ; Tsutsui, Noriaki; Ebine, Masumi ; Birumachi, Atsushi

A position-sensitive scintillation detector module for a new protein neutron diffractometer was developed by using a scintillator / wavelength shifting (WLS) fiber technology. The detector module has a spatial resolution of 2.5 mm with a neutron-sensitive area of 320 320 mm. The WLS fibers are arranged in a regular pitch of 2.5 mm in x and y direction and those arrays are placed diagonally. The light reflecting grid is inserted in between the fibers in order for optical isolation and for mechanical support of the fiber. The detector implemented flat Li/ZnS screens up and downstream of the WLF fiber arrays. The detector exhibited a detection efficiency of 30-50% for thermal neutron (depending on -ray sensitivities) and a count uniformity of ~13%. In this paper detailed detector design and experimental results obtained using a pulsed neutron beam are presented.