Kropat G, Baechler S, Bailat C, Barazza F, Bochud F, Damet J, Meyer N, Palacios Gruson M, Butterweck G
Institute of Radiation Physics, Lausanne, Switzerland
Swiss Federal Office of Public Health, Berne, Switzerland.
Radiat Prot Dosimetry. 2015 Nov;167(1-3):302-5. doi: 10.1093/rpd/ncv267. Epub 2015 May 5.
Swiss national requirements for measuring radon gas exposures demand a lower detection limit of 50 kBq h m(-3), representing the Swiss concentration average of 70 Bq m(-3) over a 1-month period. A solid-state nuclear track detector (SSNTD) system (Politrack, Mi.am s.r.l., Italy) has been acquired to fulfil these requirements. This work was aimed at the calibration of the Politrack system with traceability to international standards and the development of a procedure to check the stability of the system. A total of 275 SSNTDs was exposed to 11 different radon exposures in the radon chamber of the Secondary Calibration Laboratory at the Paul Scherrer Institute, Switzerland. The exposures ranged from 50 to 15000 kBq h m(-3). For each exposure of 20 detectors, 5 SSNTDs were used to monitor possible background exposures during transport and storage. The response curve and the calibration factor of the whole system were determined using a Monte Carlo fitting procedure. A device to produce CR39 samples with a reference number of tracks using a (241)Am source was developed for checking the long-term stability of the Politrack system. The characteristic limits for the detection of a possible system drift were determined following ISO Standard 11929.
瑞士关于测量氡气暴露量的国家要求规定，检测下限为50 kBq h m⁻³，这代表了瑞士在1个月内70 Bq m⁻³的浓度平均值。为满足这些要求，购置了一套固态核径迹探测器（SSNTD）系统（Politrack，Mi.am s.r.l.，意大利）。这项工作旨在将Politrack系统校准至可追溯国际标准，并制定一套程序来检查该系统的稳定性。在瑞士保罗谢勒研究所二级校准实验室的氡气室内，总共275个SSNTD被暴露于11种不同的氡气暴露量环境中。暴露量范围为50至15000 kBq h m⁻³。对于每次20个探测器的暴露，使用5个SSNTD来监测运输和储存过程中可能的本底暴露。使用蒙特卡罗拟合程序确定了整个系统的响应曲线和校准因子。开发了一种使用²⁴¹Am源产生具有参考径迹数的CR39样品的装置，用于检查Politrack系统的长期稳定性。根据ISO标准11929确定了检测可能的系统漂移的特征限值。
