title: Characterization of gamma rays existing in the NMIJ standard neutron field.
abstract: Our laboratory provides national standards on fast neutron fluence. Neutron fields are always accompanied by gamma rays produced in neutron sources and surroundings. We have characterised these gamma rays in the 5.0 MeV standard neutron field. Gamma ray measurement was performed using an NE213 liquid scintillator. Pulse shape discrimination was incorporated to separate the events induced by gamma rays from those by neutrons. The measured gamma ray spectra were unfolded with the HEPRO program package to obtain the spectral fluences using the response matrix prepared with the EGS4 code. Corrections were made for the gamma rays produced by neutrons in the detector assembly using the MCNP4C code. The effective dose equivalents were estimated to be of the order of 25 microSv at the neutron fluence of 10(7) neutrons cm(-2).
authors.affiliation: National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8568, Japan. h-harano@aist.go.jp
authors.forename: H
authors.initials: H
authors.lastname: Harano
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Y
authors.initials: Y
authors.lastname: Ito
authors.forename: A
authors.initials: A
authors.lastname: Uritani
authors.forename: K
authors.initials: K
authors.lastname: Kudo
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D019544:Equipment Failure Analysis / Q000379:methods / Q000592:standards; D005720:Gamma Rays; D007564:Japan; D008956:Models, Chemical; D009502:Neutrons; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods / Q000592:standards*; D011874:Radiometry / Q000379:methods* / Q000592:standards*; D012015:Reference Standards; D012542:Scattering, Radiation