医院中子照射器中子束流出口处热中子注量率的测量

医院中子照射器是基于微型反应堆而设计的专门用于硼中子俘获治疗（BNCT）的核反应堆装置，其额定功率为30 kW。在堆芯相对两侧分别设有一条热中子束流和超热中子束流用于病人照射，在热中子束流内引出一条实验用热中子束流，用于瞬发γ法测量病人血硼浓度。本工作利用²³⁵U裂变靶和白云母探测片测量了热、超热和实验用热中子束流出口处的热中子绝对注量率。结果显示，在30 kW额定功率运行时，热、超热和实验用热中子束流出口处的热中子注量率分别为1.67×10⁹、2.44×10⁷和3.03×10⁶ cm^-2•s^-1。以上结果达到了BNCT设计要求，并能满足瞬发γ测量血硼浓度的要求。

Measurement of Thermal Neutron Fluence Rate of In-hospital Neutron Irradiator by SSNTD

In-hospital neutron irradiator (IHNI) is an especially designed nuclear device based on Miniature Neutron Source Reactor (MNSR) for boron neutron capture therapy (BNCT). Its rated power is 30 kW. There are a thermal neutron beam and an epithermal neutron beam for treating patients at the opposite of the core. From the thermal neutron beam, a test beam is fetched out for measurement of boron concentration in blood by prompt γ neutron activation analysis (PGNAA) method. The neutron fluence rates at the end of thermal, epithermal and test neutron beam were measured by ²³⁵U fissile target and mica slice detector. At rated power, they are 1.67×109, 2.44×10⁷ and 3.03×10⁶ cm^-2•s^-1, respectively. The results show that the thermal and epithermal neutron fluence rate can meet the requirement of BNCT and test neutron fluence rate meets the requirement of PGNAA.