Nadar M Y, Akar D K, Mishra L, Patni H K, Singh I S, Sawant P D
Radiation Safety Systems Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
Radiation Safety Systems Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
Appl Radiat Isot. 2021 Jul;173:109721. doi: 10.1016/j.apradiso.2021.109721. Epub 2021 Apr 13.
In-vivo lung monitoring is an important technique for the assessment of internal dose of radiation workers handling actinides. At BARC, counting efficiencies (CEs) of detection systems used for estimation of natural uranium in the lungs are evaluated using realistic thorax physical phantoms or computational voxel phantoms. The quantification of U and U in lungs is done using CEs determined at 63.3 keV and 185.7 keV photon energies respectively. These CEs can also be used for assessment of enriched uranium in the lungs of the workers. In this study, spectra are generated for HPGe array detectors using Monte Carlo simulations of various enriched uranium compositions distributed in the lungs of thorax voxel phantom. A methodology is developed to predict the U enrichment from lung spectrum analysis using the ratio of net counts in 185.7 keV and 63.3 keV energy regions. It is possible to estimate enrichments in the range of 2%-30% using the developed method with less than ±9% error. Finally, effect of U enrichment on dose assessment using lung monitoring method is studied.
体内肺部监测是评估处理锕系元素的辐射工作人员体内剂量的一项重要技术。在巴巴原子研究中心，使用逼真的胸部物理模型或计算体素模型来评估用于估算肺部天然铀的检测系统的计数效率（CE）。肺部中铀-234和铀-238的定量分别使用在63.3keV和185.7keV光子能量下测定的计数效率来完成。这些计数效率也可用于评估工作人员肺部的浓缩铀。在本研究中，通过对分布在胸部体素模型肺部的各种浓缩铀成分进行蒙特卡罗模拟，为高纯锗阵列探测器生成能谱。开发了一种方法，利用185.7keV和63.3keV能量区域的净计数比，通过肺部能谱分析预测铀的富集度。使用所开发的方法，可以估计2%-30%范围内的富集度，误差小于±9%。最后，研究了铀富集对使用肺部监测方法进行剂量评估的影响。
