The calibration of Bonner sphere spectrometer.

: Bonner sphere spectrometer (BSS) is used in radiation protection measurement because of its wide energy range (thermal to MeV) and easy operation. Mitsubishi Heavy Industries (MHI) has used BSS to obtain neutron spectrum and has used the neutron spectrum to estimate neutron dose or induced activity. Calibration of BSS is important to estimate precise neutron dose or induced activity. MHI BSS was calibrated at National Institute of Advanced Industrial Science and Technology (AIST). The calibration results at AIST are in good agreement with calculation results.