Verification of KERMA factor for beryllium at neutron energy of 14.2 MeV based on charged-particle measurement

Kondo, Keitaro; Ochiai, Kentaro; Murata, Isao*; Konno, Chikara  

In previous direct measurements of nuclear heating for beryllium induced with DT-neutrons, it was pointed out that the calculation with JENDL-3.2 underestimated the measured one by 25 %. However, reasons of this large discrepancy have not been understood clearly. In order to reveal the reason of this discrepancy, we examined KERMA factors for beryllium deduced with three latest nuclear data libraries: JENDL-3.3, ENDF/B-VII.0 and JEFF-3.1. As a result, the partial KERMA factors for Be(n,2n+2) reaction channel at incident neutron energy of 14.2 MeV deduced from JENDL-3.3 was significantly smaller than that deduced from the other libraries. These partial KERMA factors were compared with a new partial KERMA factor calculated based on our experimental model from our recent measurement of the -particle emission double-differential cross-section for beryllium. The partial KERMA factor from JENDL-3.3 was smaller by 20 % than our experiment-based one. The reason of the discrepancy in the previous nuclear heating measurement comes from smaller partial KERMA factor for beryllium in JENDL-3.3, which is caused by significant underestimation of higher energy part of -particle emission DDX at forward emission angles.