Endo S, Hoshi M, Tauchi H, Takeoka S, Kitagawa K, Suga S, Maeda N, Komatsu K, Sawada S, Iwamoto E
Research Institute for Radiation Biology and Medicine, Hiroshima University, Japan.
J Radiat Res. 1995 Jun;36(2):91-102. doi: 10.1269/jrr.36.91.
A neutron generator (HIRRAC) for use in radiobiology study has been constructed at the Research Institute for Radiation Biology and Medicine, Hiroshima University (RIRBM). Monoenergetic neutrons of which energy is less than 1.3 MeV are generated by the 7Li(p,n)7 Be reaction at proton energies up to 3 MeV. The protons are accelerated by a Schenkel-type-accelerator and are bombared onto the 7Li-target. An apparatus for the irradiation of biological material such as mice, cultured cells and so on, was designed and will be manufactured. Neutron and gamma-ray dose rates were measured by paired (TE-TE and C-CO2) ionization chambers. Contamination of the gamma ray was less than about 6% when using 10-microns-thick 7Li as a target. Maximum dose rates for the tissue equivalent materials was 40 cGy/min at a distance of 10 cm from the target. Energy distributions of the obtained neutrons have been measured by a 3He-gas proportional counter. The monoenergetic neutrons within an energy region from 0.1 to 1.3 MeV produced by thin 7Li or 7LiF targets had a small energy spread of about 50 keV (1 sigma width of gaussian). The energy spread of neutrons was about 10% or less at an incident proton energy of 2.3 MeV. We found that HIRRAC produces small energy spread neutrons and at sufficient dose rates for use in radiobiology studies.
广岛大学辐射生物学与医学研究所（RIRBM）建造了一台用于放射生物学研究的中子发生器（HIRRAC）。通过7Li（p，n）7Be反应，在质子能量高达3 MeV的情况下，产生能量小于1.3 MeV的单能中子。质子由 Schenkel 型加速器加速，并轰击到7Li靶上。设计并将制造一种用于照射生物材料（如小鼠、培养细胞等）的装置。通过配对的（TE - TE和C - CO2）电离室测量中子和γ射线剂量率。当使用10微米厚的7Li作为靶时，γ射线的污染小于约6%。在距靶10 cm处，组织等效材料的最大剂量率为40 cGy/min。通过3He气体正比计数器测量了所获得中子的能量分布。由薄7Li或7LiF靶产生的能量在0.1至1.3 MeV范围内的单能中子具有约50 keV的小能量展宽（高斯分布的1σ宽度）。在入射质子能量为2.3 MeV时，中子的能量展宽约为10%或更小。我们发现HIRRAC产生能量展宽小的中子，且剂量率足以用于放射生物学研究。
