A low background neutron measuring system and its application to the detection of neutrons produced by the D2O electrolysis

Abstract A low background neutron measuring system has been constructed. The background neutron counting rate is 1.4 counts/h and the long term stability is within 0.1 counts/h over one year. The detection efficiency for fission neutrons from 252 Cf is 4.4%. The system is capable of measuring low rate neutron emission events with a half life of 10 20 yr. The rate of neutron production from copper and lead by cosmic-rays was measured in an underground laboratory. The system was used for an experimental test of neutron emission from the electrolysis of D 2 O. The results show no enhancement of neutron emission. No tritium production was observed.