Position-sensitive neutron detection with 6LiF layers on silicon semiconductors

The detection of thermal neutrons absorbed by a thin layer of 6LiF in front of a p− n n+ Silicon diode has been demonstrated. With such a layer attached to a strip diode a linear position-sensitive neutron detector is presented. A spatial resolution of 1.25 mm was measured, and it is equal to the pitch of the 24 metal strips on the 30 mm × 30 mm diode array. The absorption probability is 10% and 30% and for double diodes this leads to a detector efficiency of 5% and 15% for thermal and subthermal neutrons, respectively. These values can be improved by various means. For MeV gamma rays an extremely low sensitivity of less than 10−6 has been measured with 60Co and 137Cs and with gamma rays generated by stopping a strong neutron beam with Cadmium in front of the detector. Further properties of this new neutron detector based on absorption in 6LiF and generation of charge carriers within the depletion region of a Silicon diode along the trace of generated high energy 3H+ ions are presented.