Silesian Centre for Environmental Radioactivity, Central Mining Institute, Katowice, Poland.
Silesian Centre for Environmental Radioactivity, Central Mining Institute, Katowice, Poland.
J Environ Radioact. 2021 Aug;234:106616. doi: 10.1016/j.jenvrad.2021.106616. Epub 2021 Apr 24.
The calibration of monitors of radon decay products is a difficult task, and even more so in the case of monitors detecting the products of thoron decay. An important issue here is the lack of primary standards, both in relation to the products of radon as well as thoron decay. In Poland, for many years, measurements of potential alpha energy concentration (PAEC) were carried out with the application of special devices, called ALFA probes. These in turn featured thermo-luminescent detectors (TLD), the readout of which provided information about the potential alpha energy, with no dependence on equilibrium or other factors alike. In this paper, we propose modifying this technique, which had been used only for measurements of products of radon decay. We specifically examine how it can be used to allow simultaneous measurements of radon and thoron PAECs. In employing the method, the idea is to use two sets of TL detectors in the same device during and after sampling. The first set of detectors is used to store the energy of alpha particles during the course and for a short while after the sampling, up to 5 h after its end. Using this method, the first set of detectors holds respectively the full and partial PAECs of products of radon and thoron decay. After that, the first set of TLDs is replaced with a second one. These are then left in the device for another 55-60 h. This set contains only the PAEC from thoron decay products. Afterwards, it is necessary to subtract thoron PAEC from the first set result and add it to the result provided by the second set in order to estimate the PAEC for the products of thoron decay. On a practical level, using such a procedure can potentially difficult during underground or field monitoring nevertheless. This is why another approach can be adopted as well. This is specifically to leave the device for 60 h after sampling without any changes, the original set of TLDs providing a "total" PAEC readout - this being a sum of radon and thoron PAECs. In this paper, we will explore the value of using such a readout for the measurement that is carried out.
氡衰变产物监测器的校准是一项艰巨的任务，对于探测钍衰变产物的监测器来说更是如此。这里的一个重要问题是缺乏初级标准，无论是与氡衰变产物还是钍衰变产物有关。在波兰，多年来，人们一直应用特殊装置（称为 ALFA 探头）进行潜能α能量浓度（PAEC）的测量。这些探头又配备了热释光探测器（TLD），其读数提供了关于潜能α能量的信息，与平衡或其他类似因素无关。在本文中，我们提出修改该技术，该技术仅用于测量氡衰变产物。我们专门研究如何将其用于同时测量氡和钍的 PAEC。在采用该方法时，想法是在采样期间和之后在同一装置中使用两组 TL 探测器。第一组探测器用于在采样过程中和结束后不久（最长可达 5 小时）存储α粒子的能量。使用这种方法，第一组探测器分别包含氡和钍衰变产物的完整和部分 PAEC。之后，将第一组 TLD 替换为第二组。这些探测器将留在装置中另外 55-60 小时。这组探测器仅包含来自钍衰变产物的 PAEC。之后，有必要从第一组的结果中减去钍 PAEC，并将其添加到第二组的结果中，以估计来自钍衰变产物的 PAEC。在实际水平上，尽管如此，在地下或现场监测中，使用这样的程序可能会有潜在的困难。这就是为什么也可以采用另一种方法。这具体是指在采样后 60 小时内不进行任何更改，原始 TLD 组提供“总”PAEC 读数-这是氡和钍 PAEC 的总和。在本文中，我们将探讨使用这种读数进行测量的价值。
