Upgrading of JRR-3/JRR-4 neutron beam utilities; For cold neutron beam and BNCT

JRR-3/JRR-4中性子ビーム利用の性能向上; 冷中性子ビームとBNCTのために

山本 和喜 ; 田村 格良  ; 熊田 博明; 丸尾 毅

Yamamoto, Kazuyoshi; Tamura, Itaru; Kumada, Hiroaki; Maruo, Takeshi

JRR-3冷中性子ビーム強度の増倍とJRR-4のためのホウ素中性子捕獲治療(BNCT)の進展という2つの計画について発表する。JRR-3の冷中性子ビーム強度を増加させるために、液体水素減速材容器と中性子導管を改造する。新減速材容器の中性子強度が材料と形の選択を新型減速材容器に適合させることによって、約2倍に増加でき、また、高性能スーパーミラーと交換することによって、ビーム分散を小さいまま中性子輸送効率を約5倍に改善できる見通しを得た。JRR-4ではBNCTの需要を満たすために利用効率の改善を進め、脳腫瘍以外のガンへのBNCT適用進めていく方針である。

To response to their requests, we proposed two plans. One is the enhancement of cold neutron beam intensity for JRR-3 and the other one is the progress of Boron Neutron Capture Therapy (BNCT) for JRR-4. Improvements of the liquid hydrogen moderator and the neutron guide tubes are more effective and efficient to increase cold neutron beam intensity at JRR-3. It was recently evaluated that a neutron intensity on the new moderator increases twice the current intensity by fitting selection of material and shape for the new moderator vessel. It was also evaluated that the neutron transportation efficiency at the end of curved guide tube could be improved 5 times with 3Qc super-mirrors. Although BNCT in JRR-4 has been mainly applied to therapy against brain tumor so far, technical developments to expand its application to therapy against the other cancers such as lung cancer, head and neck cancer are carried out as the needs are increasing these days.