BNCT医院中子照射器辐射场特性参数初步测量

为验证BNCT医院中子照射器的设计效果,对其辐射场的特性参数如中子能谱、中子通量密度及其空间分布、中子和γ吸收剂量率及其空间分布等进行了测量。针对该照射器的特点,建立了一套由多球谱仪、235U裂变电离室、金箔、组织等效正比计数器和热释光探测器组成的测量系统,利用蒙特卡洛计算方法优化设计探测器的结构,以提高超热能区的分辨率和甄别不同能量成分中子的能力。初步测量结果表明,该照射器的中子通量密度达到了预期设计要求。

Preliminary characterization of radiation fields of IHNI-1 for BNCT

The characteristic parameters of the neutron radiation fields produced by an in-hospital neutron irradiatior for boron neutron capture therapy(BNCT), such as neutron energy spectra, neutron flux density and neutron absorbed dose rate and their spatial distributions in free air, etc., were measured to verify the design effect. According to the traits of the irradiators, a measuring system composed of a multi-sphere spectrometer, a 235U fission ionization chamber, gold foils, a tissue equivalent proportional counter and thermoluminescent detectors was established. In order to improve the energy resolution in epithermal energy range and the ability to discriminate different neutron components, the Monte Carlo method was used for optimizing the detectors. The preliminary results show that the neutron flux densities of the irradiators achieve the expected levels.