医院中子照射器中子照射束流等效平面源研究

Study on the Equivalent Planar Source of In-Hospital Neutron Irradiator Neutron Beam

为了在医院中子照射器上开展肿瘤硼中子俘获治疗(BNCT),需要为配套的治疗计划系统SERA研制等效中子源。在医院中子照射器全堆芯模型的基础上,利用蒙特卡罗方法围绕热束和超热束中子金箔活化实验开展模拟研究,评估了屏蔽准直结构和材料以及金箔活化实验中金箔、有机玻璃等结构材料对中子束流的影响,明确了准直孔道末端锂聚乙烯材料成分及形状等是对金箔活化实验结果影响较大的因素。在此基础上,开展了全堆芯蒙卡模拟,获得热束中子结果与实验结果平均偏差-1.74%;模拟的超热束中子结果与实验结果平均偏差6.14%。在此基础上制作了治疗计划系统SERA的源,模拟的超热束中子通量与全堆芯模拟结果小于10%。

To perform tumor Boron Neutron Capture Therapy(BNCT)using In-Hospital Neutron Irradiator,an equivalent neutron source should be developed for the treatment planning software SERA.Based on the detail reactor model of In-Hospital Neutron Irradiator and gold activation experiments,a simulation study was carried out by Monte Carlo method around thermal neutron beam and epithermal neutron beam neutron.The shielding collimation structures and materials as well as the effects of structural materials such as gold foil and plexiglass on neutron beam current in the gold activation experiments were evaluated.It shows that the composition and shape of lithium polyethylene material at the end of collimating channel are the factors which have great influence on the experimental results of gold activation.Based on the real experimental conditions,the Monte Carlo simulation of the whole core is carried out,and the mean deviation between the thermal neutron beam results and the experimental results is-1.74%.The average deviation of the simulated epithermal neutron beam simulation results from the experiment results is 6.14%.On this basis,the source of the treatment planning software SERA was produced,and the deviation between the epithermal neutron beam and the detail model simulation results waswithin10%.