Fusion neutron yield and muon cycling rate in muon catalyzed dt fusion at RIKEN-RAL muon facility

Abstract

This article reports the analysis method and preliminary result of the muon Catalyzed Fusion (muCF) experiments in deuterium and tritium mixture, which were carried out at Port 1 of RIKEN (Institute of Physical and Chemical Research)-RAL (Rutherford-Appleton Laboratory) Muon Facility. The most essential muCF parameters, the muon cycling rate (lambda(sub c)) and the muon loss rate (W) can be deduced from fusion neutron information such as the neutron disappearance rate (lambda(sub n)) and the neutron yield (Y(sub n)). To get total Y(sub n), the number of the measured neutrons with more than the energy of 4 MeV was corrected by pileup and multi-hit effects (0.3 and 3 percent, respectively), and normalized by a solid angle of detectors (2.4 x 10(exp -3)) and neutron detection efficiency (10.3+/-0.1 percent). The lambda(sub c) can be deduced from Y(sub n) and lambda(sub n). The tritium concentration dependence of the lambda(sub c) is more similar to the LAMPF (Los Alamos Meson Physics Facility) result than to the PSI (Paul Scherrer Institute) result especially at high tritium concentration. Preliminary analysis indicates that the lambda(sub c) reaches its maximum value approximately 150/micro sec at tritium concentration 40 percent in the both cases of liquid and solid phase.

RIKEN(理化学研究所)-RAL(ラザフォード・アップルトン研究所)ミューオン施設の実験ポート1で行われた重水素3重水素混合物におけるミュー粒子触媒核融合(μCF)実験の解析法と予備的結果を報告する。μCFにおける最も本質的なパラメタであるミュー粒子サイクル率(λ(sub c))とミュー粒子損失率(W)は、中性子消失率(λ(sub n))や全中性子収量(Y(sub n))などの核融合中性子の情報から導き出される。Y(sub n)を得るために、測定した4MeV以上の中性子の数は、パイルアップによる影響(0.3%)とマルチヒット効果による影響(3%)で補正し、検出器の立体角(2.4×10(exp -3))と中性子検出効率(10.3±0.1%)で規格化した。ミュー粒子サイクル率は、Y(sub n)とλ(sub n)から求めることができる。λ(sub c)のトリチウム濃度依存性は、特に高トリチウム濃度においてPSI(Paul Scherrer研究所)における結果よりもLAMPF(ロスアラモス中間子物理研究施設)における結果に近い。予備的解析結果は、ミュー粒子サイクル率が液体、固体状態のいずれにおいてもトリチウム濃度が40%で約150/マイクロ秒の最高値に到達することを示している。