Present status of calibration fields and collaborative activities at the Facility of Radiation Standards (FRS), Japan Atomic Energy Agency (JAEA)

Kowatari, Munehiko; Yoshitomi, Hiroshi   ; Nishino, Sho   ; Tanimura, Yoshihiko   ; Murayama, Takashi; Oishi, Tetsuya ; Yoshizawa, Michio  

As a one of leading secondary standard dosimetry laboratories (SSDL) in Asian-Pacific region, the Facility of Radiation Standards (FRS) in Japan Atomic Energy Agency (JAEA) has been offering reliable radiation calibration fields for more than three decades. After the installation of the 4 MV Van-de-Grraff accelerator in 2000, mono-energetic neutron calibration fields and the ISO specified R-F high energy -ray calibration field were established. Consequently, the FRS has been serving X-ray and -ray calibration fields ranging from 16.5 keV (for X-ray narrow series) to 6-7 MeV (for R-F high energy -ray). With regard to neutron calibration fields, the FRS has been providing the ISO specified RI neutron calibration fields (Cf, AmBe and DO-moderated Cf), thermal neutron fields (0.025 eV) and ten different energies of mono-energetic neutron calibration fields with energies between 8 keV and 19 MeV. The latest accomplishment in recent years is the establishment of the graphite moderated AmBe neutron calibration field as a workplace simulated neutron field. This also gives practically reliable calibration factors for neutron dosimeters to be used in nuclear facilities.