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目的寻求简易可靠的方法优化核算医用加速器机房防护门口处辐射屏蔽的厚度。方法采用简易法和IAEA 47号报告对某15 MV医用加速器机房门的屏蔽厚度进行核算。结果按照国家标准规定的剂量限值,采用IAEA 47报告核算机房门屏蔽厚度,对于标称能量≥10 MV的加速器,γ射线与散漏射线的总屏蔽厚度值都要大于简易法的核算值,中子屏蔽厚度值不一定要大;对于标称能量<10 MV的加速器(不需屏蔽中子),IAEA 47报告核算的屏蔽厚度值不一定要大。结论 IAEA 47报告计算繁琐复杂,所需利用的参数和需利用难以准确的数据较多,计算繁冗容易出现纰漏。因此,我们选取两种方法核算,选取较大值进行设计,在随后加速器工作场所防护验收检测中,辐射屏蔽都可行,符合国家标准的要求。
Objective To seek a simple and reliable method to optimize the thickness of the radiation shielding at the door of the medical accelerator room. Methods The shield thickness of a 15 MV medical accelerator room door was calculated using the simplified method and IAEA 47 report. Results In accordance with the dose limits prescribed by national standards, IAEA 47 was used to report the door shielding thickness of the computer room. For an accelerator with a nominal energy ≥10 MV, the total shielding thickness of γ-rays and scattered radiation should be greater than the simple method , Neutron shielding thickness values are not necessarily large; IAEA 47 reported shielding thickness values need not necessarily be large for accelerators with nominal energy <10 MV (no neutron shielding required). Conclusions The IAEA 47 report is computationally complicated and requires more parameters to be used and more data to be used, which are difficult to be accurately calculated and flawed in calculation. Therefore, we choose two methods of accounting, select the larger value for the design, accelerator testing in the subsequent acceptance of the workplace protection, radiation shielding is feasible, in line with national standards.