Thought Experiment to Examine Benchmark Performance for Fusion Nuclear Data

There are many benchmark experiments carried out so far with DT neutrons especially aiming at fusion reactor development. These integral experiments seemed vaguely to validate the nuclear data below 14 MeV. However, no precise studies exist now. The author’s group thus started to examine how well benchmark experiments with DT neutrons can play a benchmarking role for energies below 14 MeV. Recently, as a next phase, to generalize the above discussion, the energy range was expanded to the entire region. In this study, thought experiments with finer energy bins have thus been conducted to discuss how to generally estimate performance of benchmark experiments. As a result of thought experiments with a point detector, the sensitivity for a discrepancy appearing in the benchmark analysis is “equally” due not only to contribution directly conveyed to the deterctor, but also due to indirect contribution of neutrons (named (A)) making neutrons conveying the contribution, indirect controbution of neutrons (B) making the neutrons (A) and so on. From this concept, it would become clear from a sensitivity analysis in advance how well and which energy nuclear data could be benchmarked with a benchmark experiment

Experimental study on breakup reaction of beryllium and carbon induced with 14-MeV neutrons based on emitted charged-particle measurements

Detailed measurements of α-particle emission double differential cross section for beryllium and carbon with 14-MeV incident neutrons were carried out. In order to identify contributing reaction channels to the 9Be(n,2n + 2α) and 12C(n,n' + 3α) reactions, we attempted to reproduce energy distributions of emitted particles by Monte Carlo calculations according to reaction kinematics of a lot of channels which contribute to the reactions. As for the 9Be(n,2n + 2α) reaction, a contribution of the 9Be(n,α)6He* channels and the simultaneous breakup channel was suggested to account for the energy and angular distribution of emitted α-particles and neutrons. As for the 12C(n,n' + 3α) reaction, the 12C(n,α)9Be* channels were largely contributed and well reproduced the experimental data