Response of photomultiplier tube to 14 MeV pulse neutron irradiation

The response of photomultiplier tube (PMT) to scattered neutron and gamma ray is a severe interfere factor in low sensitivity scintillation neutron detection system. The response waveforms of PMT to 14.1 MeV pulse neutron is measured upon the ING-103 DPF pulse neutron source system, using two different types of PMT (EMI-9815B and EMI-9850B). To ensure the DPF source produce pulse neutron and X-ray simultaneously, it is essential to eliminate the X-ray's interference. Through time of flight (TOF) method, the neutron and X-ray pulse are separated because of their different arriving time at the ulterior detection point. The net neutron pulse is detected by adding a Pb absorber in the beam channel to restrain the X-ray. The experimental sensitivity of the EMI-9815B and EMI-9850B are 10-13 and 10-15 magnitude, respectively, it agreed well with the calculational results by MCNP Monte-Carlo program. (authors)