  A 3-D position sensitive neutron detector is being developed based on a
plastic scintillator array. A double side SiPM readout is used to determine the
depth of interaction (DOI) in each scintillator unit. In the preliminary test,
the DOI in a 254 x 6 x 6 mm3 SP101 plastic scintillator is measured at
different positions using a collimated Co-60 source. The SiPM (KETEK PM6660)
signals are recorded by a 2.5 GS/s digital oscilloscope. The DOI results are
calculated using both the amplitude and the temporal information. Position
resolutions (FWHM) of 2.5 cm and 6.6 cm are realized, respectively. A detector
based on a 2-D array is capable of recording the 3-D position information of
the incident neutron. The 3-D detector is to be used together with a neutron
time projection chamber as a directional fast neutron detector. According to
the simulation results, the angular resolution (8 degree FWHM) is much better
than that of a typical neutron scatter camera.
