Szeiler G, Somlai J, Ishikawa T, Omori Y, Mishra R, Sapra B K, Mayya Y S, Tokonami S, Csordás A, Kovács T
Institute of Radiochemistry and Radioecology, University of Pannonia, PO Box 158, H-8201 Veszprem, Hungary.
Radiat Prot Dosimetry. 2012 Nov;152(1-3):243-6. doi: 10.1093/rpd/ncs231. Epub 2012 Aug 26.
More than half of the radiation dose of natural origin comes from radon. However, according to some surveys in certain cases, the radiation dose originating from thoron may be considerable. Among the factors disturbing the measurement of radon, the presence of thoron may also influence the measured radon value, making the estimated radiation exposure imprecise. Thoron has previously been surveyed, mainly in Asia; however, recent surveys for some European locations have found that significant thoron concentrations also need to be considered. In this survey, several types of commercially available SSNTDs (solid-state nuclear track detectors) capable of measuring both radon and thoron were placed at the same time in 73 houses and 7 workplaces in Hungary with 3-month exposition periods. In order to measure thoron, the distance of the detector sets was fixed as 15-20 cm from the walls. The radon concentration was measured with five types of SSNTDs: NRPB, NRPB SSI, Raduet, DTPS and DRPS. The first four types had relatively good accordance (within ± 10 %), but the results of the DRPS detectors were considerably lower when compared with other detectors for radon concentrations over 100 Bq m(-3). The thoron averages were provided by two different types of detectors: Raduet and DTPS. The difference between their average results was more than 30 % and was six times the maximum values. Therefore, the thoron measurement results were judged to be erroneous, and their measurement protocol should be clearly established for future work.
超过一半的天然辐射剂量来自氡。然而，根据某些特定情况下的调查，钍射气产生的辐射剂量可能相当可观。在干扰氡测量的因素中，钍射气的存在也可能影响所测的氡值，导致估计的辐射暴露不准确。此前主要在亚洲对钍射气进行过调查；然而，最近对欧洲一些地点的调查发现，钍射气的显著浓度也需要考虑。在本次调查中，几种能够同时测量氡和钍射气的市售固态核径迹探测器（SSNTDs）被同时放置在匈牙利的73所房屋和7个工作场所中，暴露期为3个月。为了测量钍射气，探测器组距离墙壁的距离固定为15 - 20厘米。用五种类型的SSNTDs测量氡浓度：NRPB、NRPB SSI、Raduet、DTPS和DRPS。前四种类型的结果相对吻合（在±10%以内），但当氡浓度超过100 Bq m(-3)时，DRPS探测器的结果与其他探测器相比明显更低。钍射气的平均值由两种不同类型的探测器提供：Raduet和DTPS。它们的平均结果之间的差异超过30%，是最大值的六倍。因此，钍射气的测量结果被判定有误，其测量方案应在未来工作中明确确立。
