Abstract The proton irradiation in a PET cyclotron produces radioactive by-products with high levels of activity in the target components, which are strongly dependent on the specific parameters used in the cyclotron facility. Because the target assembly parts must be replaced periodically, external exposure to operators must be assessed. In this work, high-resolution gamma-ray spectrometry was used to determine the activity levels for the specific radionuclides induced in the target components of a medical 9.6 MeV MINItrace cyclotron. The focus was on three target components, which are periodically replaced: Havar foil, Titanium foil and the Helicoflex seal located on the path of the proton beam just in front of the silver vessel containing the enriched water. Eight radionuclides were identified in the Havar foil: 54Mn, 56Co, 57Co, 58Co, 60Co, 95Tc, 109Cd and 183Re. In the titanium foil, the nuclides 46Sc, 48V, 51Cr, 56Co, 57Co, and 75Se were identified, while only 51Cr, 58Co, and 60Co were detected in the Helicoflex seal. The total effective dose rates to which staff are exposed at the moment of replacing the target were calculated. The waste management for these target components was also considered, using the half-lives of the detected radionuclides in order to determine the time necessary for the activity levels in the target components to be below the exemption levels recommended by the IAEA.

中文翻译：

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用于正电子发射断层扫描的回旋加速器中激活目标成分的伽马射线测量

摘要 PET 回旋加速器中的质子辐照会在目标组件中产生具有高活性的放射性副产物，这在很大程度上取决于回旋加速器设施中使用的特定参数。由于必须定期更换目标装配部件，因此必须评估操作员的外部暴露。在这项工作中，高分辨率伽马射线光谱法用于确定医疗 9.6 MeV MINItrace 回旋加速器的目标组件中诱发的特定放射性核素的活性水平。重点是三个目标组件，它们会定期更换：哈瓦箔、钛箔和 Helicoflex 密封件，位于质子束路径上，正好位于装有富集水的银容器前面。在哈瓦箔中鉴定出八种放射性核素：54Mn、56Co、57Co、58Co、60Co、95Tc、109Cd 和 183Re。在钛箔中，鉴定出核素 46Sc、48V、51Cr、56Co、57Co 和 75Se，而在 Helicoflex 密封件中仅检测到 51Cr、58Co 和 60Co。计算了工作人员在更换靶时所受到的总有效剂量率。还考虑了对这些目标成分的废物管理，利用检测到的放射性核素的半衰期来确定目标成分的活度水平低于 IAEA 建议的豁免水平所需的时间。