A framework for exposure characterization and gamma dosimetry at the NMBU FIGARO irradiation facility

<b>Purpose</b>: The FIGARO low dose ⁶⁰Co gamma irradiation facility at the Norwegian University of Life Sciences, Ås, Norway, is dedicated to the study of effects on living organisms from acute or chronic ionizing radiation exposures, either alone or in combination with other stressors such as UV radiation, metals or radionuclides. Here, we present a framework of working guidelines and computer software for characterization of absorbed dose rates and accumulated doses to organisms exposed within the continuous gamma field at FIGARO. The aims of the framework are to ensure gamma exposures are well characterized, that results from exposures are correctly interpreted in terms of absorbed dose rates and accumulated doses, and that sufficient information is available so that exposures can be reproduced later or at other facilities. <b>Methods</b>: The software of the framework includes a Geant4 application for Monte Carlo radiation transport simulations and tools for dose planning, recording and reporting. The working guidelines are prepared for expert users who provide simulated, calculated or estimated absorbed dose rates and for regular users who conduct exposure experiments and are responsible for record keeping. To demonstrate the developed framework, we use a case study where 14 freshwater microcosms are exposed to four levels of gamma dose rates at FIGARO. <b>Conclusion</b>: The framework guides users towards good dosimetry practices. Lessons learned could be transferable to other gamma irradiation facilities.

研究目的：位于挪威阿斯市挪威生命科学大学的FIGARO低剂量钴-60（⁶⁰Co）伽马辐照装置，专门用于探究急性或慢性电离辐射（单独或与紫外线辐射、金属、放射性核素等其他应激源联合作用）对活体生物的影响。本研究提出一套可用于表征FIGARO连续伽马场中受照生物体吸收剂量率与累积剂量的工作指南框架与计算机软件。该框架的目标在于：确保伽马辐照的剂量表征精准规范，使辐照实验结果可基于吸收剂量率与累积剂量得到正确解读，并留存足够详实的实验信息，以便后续或其他辐照装置能够复现该辐照过程。

研究方法：该框架配套的软件包含用于蒙特卡洛辐射输运模拟的Geant4应用程序，以及剂量规划、记录与报告工具。本工作指南面向两类用户制定：一类是提供模拟、计算或估算吸收剂量率的专业用户，另一类是开展辐照实验并负责实验记录的常规用户。为演示所开发的框架，本研究采用了一项案例研究：将14个淡水微宇宙置于FIGARO装置中，接受4个梯度的伽马剂量率辐照。

研究结论：该框架可指导用户遵循规范的剂量学操作流程，其积累的经验教训可推广至其他伽马辐照装置。