Stanford N, McCurdy D E
Yankee Atomic Electric Company, Bolton, MA 01740.
Health Phys. 1990 Jun;58(6):691-704. doi: 10.1097/00004032-199006000-00001.
Modern whole-body dosimeters are often required to accurately measure the absorbed dose in a wide range of radiation fields. While programs are commonly developed around the fields tested as part of the National Voluntary Accreditation Program (NVLAP), the actual fields of application may be significantly different. Dose algorithms designed to meet the NVLAP standard, which emphasizes photons and high-energy beta radiation, may not be capable of the beta-energy discrimination necessary for accurate assessment of absorbed dose in the work environment. To address this problem, some processors use one algorithm for NVLAP testing and one or more different algorithms for the work environments. After several years of experience with a multiple algorithm approach, the Dosimetry Services Group of Yankee Atomic Electric Company (YAEC) developed a one-algorithm system for use with a four-element TLD badge using Li2B4O7 and CaSO4 phosphors. The design of the dosimeter allows the measurement of the effective energies of both photon and beta components of the radiation field, resulting in excellent mixed-field capability. The algorithm was successfully tested in all of the NVLAP photon and beta fields, as well as several non-NVLAP fields representative of the work environment. The work environment fields, including low- and medium-energy beta radiation and mixed fields of low-energy photons and beta particles, are often more demanding than the NVLAP fields. This paper discusses the development of the algorithm as well as some results of the system testing including: mixed-field irradiations, angular response, and a unique test to demonstrate the stability of the algorithm. An analysis of the uncertainty of the reported doses under various irradiation conditions is also presented.
现代全身剂量计常常需要在广泛的辐射场中精确测量吸收剂量。虽然相关程序通常是围绕作为国家自愿认可计划（NVLAP）一部分所测试的辐射场开发的，但实际应用的辐射场可能有很大不同。旨在满足NVLAP标准（该标准强调光子和高能β辐射）的剂量算法，可能无法实现准确评估工作环境中吸收剂量所需的β能量辨别。为解决这个问题，一些处理器在NVLAP测试时使用一种算法，而在工作环境中使用一种或多种不同算法。经过数年采用多算法方法的实践，扬基原子电力公司（YAEC）的剂量测定服务小组开发了一种单算法系统，用于配备使用Li2B4O7和CaSO4磷光体的四元素热释光剂量计徽章。该剂量计的设计允许测量辐射场中光子和β成分的有效能量，从而具备出色的混合场测量能力。该算法在所有NVLAP光子和β辐射场以及几个代表工作环境的非NVLAP辐射场中都成功通过了测试。工作环境辐射场，包括低能和中能β辐射以及低能光子和β粒子的混合场，通常比NVLAP辐射场要求更高。本文讨论了该算法的开发以及系统测试的一些结果，包括：混合场辐照、角响应以及一项用于证明算法稳定性的独特测试。还给出了在各种辐照条件下所报告剂量的不确定度分析。
