title: Environmental neutron measurements around nuclear facilities with moderated-type neutron detector.
abstract: A cylindrical BF3 counter with cylindrical polyethylene moderators of 1-, 3-, 6- and 10-cm wall thickness were developed for neutron spectrometry, having response functions calculated by the time-dependent multi-group Monte Carlo code, TMMCR, and evaluated by a time-of-flight experiment in the energy region from epithermal to about 50 keV. This system of neutron detectors was used to measure the environmental neutron spectrum and dose equivalent around a 252Cf fission neutron source, a fast neutron source reactor, a cyclotron and an electron synchrotron. The neutron spectrum and dose obtained by this detector system showed very good agreement with those measured by a commercially available neutron rem counter and calculated by our MMCR Monte Carlo code. As a result of these comparisons, this detector system has been established as a standard spectrometer and dosimeter for environmental measurements around nuclear facilities.
mesh_terms: D000398:Air Pollution, Radioactive / Q000032:analysis*; D001880:Boranes; D002142:Californium; D009502:Neutrons; D009688:Nuclear Reactors; D010315:Particle Accelerators; D011834:Radiation Monitoring / Q000295:instrumentation*; D011874:Radiometry / Q000295:instrumentation
chemical_list: D001880:Boranes; C021274:boron trifluoride; D002142:Californium