Diagnosis of neutron sensitivity within a scintillator/wavelength-shifting fiber coil element by using a collimated pulsed neutron beam

We have developed a position-sensitive tubular scintillation neutron detector as an alternative to a
³
He gas based detector. The detector comprises a number of individual neutron-sensitive elements, where a pair of wound wavelength-shifting fiber coils is sandwiched with two rolled ZnS/
⁶
LiF scintillator screens in each element. Position-dependent neutron sensitivity within the scintillator / wavelength-shifting fiber coil (SFC) element was evaluated by using a collimated pulsed neutron beam at the J-PARC MLF. The collimated beam that has a size of 1 × 1 mm
²
scanned over the SFC element. Neutron counts were recorded and plotted as a function of incident beam position. The scanning results showed less neutron sensitivity at the juncture of the rolled scintillator screens, which indicated a lack of scintillator materials due to imperfect manufacturing process.