AbstractNeutron leakage spectra through copper slab assemblies with thicknesses of 5.8 cm and 11.8 cm have been experimentally obtained on an absolute basis using proton recoil technique and differentiation unfolding procedure. The measured results have been compared with calculations employing MCNP transport code and continuous energy cross section data from obsolete ENDF/B-IV and state of the art ENDF/B-VI libraries. The comparisons show a disagreement of as much as 73% of the ENDF/B-IV calculations, and an overestimation of 16% in the 1–2 MeV energy range and an 18% underprediction of the forward emitted neutrons in the 5–10 MeV interval by the ENDF/B-VI calculations.
厚さ5.8cmおよび11.8cmの銅スラブ体系を透過する中性子漏洩スペクトルを、陽子反跳法と微分展開法を用いて絶対値基準で実験的に取得した。測定結果は、MCNP輸送コードと、旧版のENDF/B-IVおよび最新のENDF/B-VIライブラリからの連続断面積データを用いた計算結果と比較した。比較の結果、ENDF/B-IV計算では最大73%の不一致が認められ、ENDF/B-VI計算では1～2MeVエネルギー範囲で16%の過大評価、5～10MeV範囲の前方散乱中性子で18%の過小評価が示された。