Paschalides J S, Marinakis G S, Petropoulos N P
Nuclear Engineering Department, Mechanical Engineering School, National Technical University of Athens, 15780 Athens, Greece.
Appl Radiat Isot. 2010 Jan;68(1):155-63. doi: 10.1016/j.apradiso.2009.08.017. Epub 2009 Sep 3.
Synthetic zeolite of 0.5nm pore size (5A) and blue silica gel were tested to determine their capability to be used as radon collectors. Tests conducted in a radon chamber under controlled conditions of temperature and relative humidity indicate that simple, inexpensive and maintenance-free passive devices containing about 250g of synthetic zeolite or about 270g of blue silica gel in open face metal canisters that can measure radon conveniently and adequately, the latter though being suitable only for dry-medium dry atmosphere with quite high radon concentrations. Both materials can be recycled for reuse, in a way similar to the recycle and reuse of active carbon. The amount of radon adsorbed in such collectors is determined by counting the gamma rays from the radon decay products. The lower limit of detection (LLD) is estimated to approximately 45Bqm(-3) for the synthetic zeolite and to approximately 350Bqm(-3) for the blue silica gel, for an exposure of 48h at a relative humidity of about 50%. In comparison, the corresponding LLD for active carbon is estimated to 10Bqm(-3). At relative humidity in the range between 10% and 50%, radon chamber experiments indicate that the measured radon in the canisters is proportional to the mean concentration of radon during the period of exposure. It is estimated that calibration uncertainty lies within +/-20% for both materials, thus suggesting that at least detectors based on the 5A synthetic zeolite presenting a reasonably low LLD, are a feasible and of similar cost alternative to activated carbon for indoors radon concentration measurements in practical situations.
对孔径为0.5纳米（5A）的合成沸石和蓝色硅胶进行了测试，以确定它们用作氡收集器的能力。在温度和相对湿度可控的氡室内进行的测试表明，在开口面金属罐中装有约250克合成沸石或约270克蓝色硅胶的简单、廉价且无需维护的被动式装置，能够方便且充分地测量氡，不过后者仅适用于氡浓度相当高的干燥中等干燥大气环境。这两种材料都可以像活性炭的回收再利用那样进行回收再利用。此类收集器中吸附的氡量通过对氡衰变产物的伽马射线进行计数来确定。对于合成沸石，在相对湿度约为50%的情况下暴露48小时，检测下限（LLD）估计约为45Bq·m⁻³；对于蓝色硅胶，检测下限估计约为350Bq·m⁻³。相比之下，活性炭的相应检测下限估计为10Bq·m⁻³。在10%至50%的相对湿度范围内，氡室实验表明，罐中测得的氡与暴露期间的氡平均浓度成正比。据估计，两种材料的校准不确定度均在±20%以内，因此表明，至少基于5A合成沸石且具有相当低检测下限的探测器，在实际情况下是用于室内氡浓度测量的一种可行且成本相近的活性炭替代品。
