Neutron calibration facility with radioactive neutron sources at KRISS.

For the purpose of radiation protection, the reference neutron field for calibration of neutron monitors was constructed using radioactive neutron sources-bare-(252)Cf, D(2)O-moderated (252)Cf and (241)Am-Be(alpha,n)-at Korea Research Institute of Standards and Science (KRISS). The well-specified neutron source with its emission rate and the anisotropy was installed at the centre of the neutron irradiation room, which is 6.6 x 7.6 x 6.3 m(3) in size. The neutron spectra of each source was measured using the Bonner sphere spectrometer (KRISS-BSS). Calculations using MCNP5 with realistic geometry and materials in the neutron irradiation room were performed. The calculations and measurements were found to be in good agreement, showing that the neutron calibration facility at KRISS is well established.