加速器主屏蔽区外剂量率解析算法与实测比较

屏蔽是确保加速器机房外关注点剂量率和剂量满足控制目标的重要措施,屏蔽厚度的优化设计一般采用解析算法,其可靠性需验证。选取加速器主屏蔽区外10个位点和1个无均整高剂量率模式的位点对加速器主屏蔽区外剂量率采用IAEA 47号报告和GBZ/T 201.2中的解析算法进行计算,并将计算结果与实测结果进行比较。结果表明,采用IAEA 47号报告中的参数计算出的主屏蔽区外剂量率值均高于采用GBZ/T 201.2中的参数的计算结果,采用GBZ/T 201.2中的参数的计算结果与实测结果更加接近,个别位点的实测结果高于采用GBZ/T 201.2中参数的计算结果,其原因可能是混凝土墙的施工厚度不足。GBZ/T 201.2的解析算法可合理估算主屏蔽区外的剂量率,在施工过程中应严格控制施工质量,确保混凝土密度、混凝土墙厚度等与设计值保持一致。

Dose Rate Analysis Algorithm and Measurement outsideAccelerator Primary Shielding Area

Shielding is an important measure to ensure that the dose rate and dose outside an accelerator room meet the control objectives. The optimization design of shield thickness generally uses some analytical algorithms and its reliability needs to be verified. Outside the primary shield of an accelerator, 10 sites and another one of flat filter free high doserate mode, are selected to perform dose rate calculation, using analytical algorithms in IAEA Report No.47 and GBZ/T 201.2. The outcomes are then compared withthe measured results. It shows that calculated values with the IAEA approach are higher than those with GBZ/T 201.2 parameters employed, with the latter much closer to measurements. However, there are some individual sites with a measured,higher than calculated dose rate, which's maybe due to insufficient concrete thickness. The analytical algorithm of GBZ/T 201.2 can reasonably estimate the dose rate outside the main shielding area. During the construction process, the project quality should be strictly controlled to ensure that the concrete density and construction thickness are consistent with the design.