Development of irradiation field for neutron capture therapy using direct neutrons from compact proton accelerator

我们研究了直接使用近阈^7Li（p，n）^7Be中子进行BNCT的靶组件的特性。我们能够澄清以下内容：1）我们通过模拟对BNCT辐照场特性与锂靶厚度的依赖性进行了参数调查。确定了中子和伽马射线通量，以验证BNCT辐照场的可用性。我们还研究了入射质子能量在1.89MeV到1.92MeV之间对辐照场的影响。所应用的评价指标是可处理协议深度（TPD）和硼剂量增强剂（BDE）厚度。2）关于靶组件中的伽马射线产生，我们在广岛大学的HIRRAC的实验表明，在1.9MeV的质子能量下，钨和钼作为背衬材料优于铜和铝。在相同的实验中，沉积了厚度为10μm的固体Li ...更多信息 在150μA下照射数小时后，W板上的一个样品已经剥落。因此，从靶寿命的观点判断，固体Li不适合实际使用。基于这一结果，我们进行了基础实验的潜在用途的薄膜液体锂靶模拟水流形成。我们证实了实际的液膜将是可能的，厚度为1 mm，宽度为50 mm，长度为50 mm，流量为30 m/s，从线性阵列的喷嘴产生，并对着导板流动。IFMIF计划中的一些重要进展和ANL小组的显著成果表明，液态Li薄膜的制备在技术上是可行的，并对其前景进行了展望。对于近阈^7Li（p，n）^7Be反应产生的中子，我们将继续开发BNCT辐照场，并将推动加速器BNCT辐照系统的未来实施。少

We examined the characteristics of the target assembly for the direct usage of near threshold^7L i(p,n)^7Be neutrons for BNCT. We were able to clarify the following :1) We performed a parametric survey, via simulation, of the dependence of the characteristics of the BNCT irradiation field on the thickness of the lithium target. Neutron and gamma ray fluxes were determined in order to verify the usability of the irradiation fields for BNCT. We also investigated the influence of incident proton energy on the irradiation field by considering energies between 1.89MeV to 1.92MeV. The evaluation indices applied were the treatable protocol depth (TPD) and boron-dose enhancer (BDE) thickness.2) Regarding gamma ray production in the target assembly, our experiment at the HIRRAC in Hiroshima University showed that tungsten and molybdenum were better than copper and aluminum as backing materials at the proton energy of 1.9MeV. During the same experiment, solid Li with thickness of 10μm deposited … More on a W plate had exfoliated after several hours of irradiation at 150μA. It was therefore judged that solid Li is not suitable for practical use from the viewpoint of target life-time. Based on this result, we performed fundamental experiments on the potential use of thin film liquid Li target simulated by water flow formation. We confirmed that practical liquid film will be possible for a thickness of 1mm at 50mm in width and 50mm in length and a flow rate of 30m/s generated from a linear array of nozzles and flowing against a guide plate.3) The liquid Li-metal flow experiment (2005) in the IFMIF project and the remarkable achievement of the group of ANL suggested that liquid Li thin film formation is technically possible and the prospect of its practical implementation is high.As to the neutrons from the near threshold^7Li (p,n) ^7Be reaction, we are going to continue to develop a BNCT irradiation field, and will push for the future implementation of accelerator BNCT irradiation system. Less