Feasibility study for measurement of double-differential neutron flux using half-Bonner sphere neutron spectrometer

Abe, Shinichiro   ; Takahashi, Fumiaki  

Non-destructive faults (the so-called soft errors) in microelectronic devices caused by environmental radiation is recognized as a reliability problem. In our previous study, it was found that the incident direction of neutrons has impact on soft error rate. Double differential flux (DDF) of environmental neutrons is estimated by PARMA 4.0, but there is no measured data. In this study, we perform feasibility study for measurement of double differential neutron flux using half Bonner sphere neutron spectrometer (HBSS) through PHITS simulation. Response functions of HBSS were calculated by PHITS. It is found that the response function change in accordance with the change of the neutron incident direction. Moreover, to validate whether DDF obtained from unfolding of HBSS data corresponds with original DDF, we are calculating irradiations of neutron with DDF obtained from PARMA 4.0 on HBSS changing the radius and direction of the hemispherical moderator.