Harley Naomi H, Chittaporn Passaporn, Fisenne Isabel M
New York University School of Medicine, New York, NY, USA.
USDOE.
Radiat Prot Dosimetry. 2017 Nov 1;177(1-2):160-163. doi: 10.1093/rpd/ncx136.
Long-term measurements of the 222Rn concentration, 222Rn decay product activity, particle size distribution, and unattached, and attached 222Rn decay products, were made at two locations using the 22 y radon decay product 210Pb as their tracer. The particle size sampler collects both short lived 222Rn decay products that ultimately decay to 210Pb on the filters, and also airborne 210Pb. The measurements were made outdoors, at a suburban home and at Fernald, OH, a former uranium processing facility, on top of one of the two 226Ra storage silos containing 150 TBq 226Ra. The size distributions showed the unattached fractions, i.e. particle diameter 2-4 nm, to be 1.5% at the home and 14% at the silos. The unattached fraction of 218Po can be shown to be an immediate measure of the 222Rn concentration. The data indicates detection of the pressure driven 222Rn flow at the silo and with the enhanced measurement capability of a filtered air source versus the usual 222Rn gas measurement. It is proposed that real time measurements of unattached 218Po may be used to identify rapidly changing 222Rn concentrations associated with pressure driven soil air flow associated with seismic activity.
使用22年的氡衰变产物210Pb作为示踪剂，在两个地点对222Rn浓度、222Rn衰变产物活度、粒径分布以及未附着和附着的222Rn衰变产物进行了长期测量。粒径采样器在滤膜上收集最终衰变为210Pb的短寿命222Rn衰变产物，同时也收集空气中的210Pb。测量是在室外进行的，一处是在郊区的一户人家，另一处是在俄亥俄州的费纳德，这是一个 former uranium processing facility，在两个装有150 TBq 226Ra的226Ra储存筒仓之一的顶部。粒径分布显示，未附着部分，即粒径为2 - 4纳米的颗粒，在住户处为1.5%，在储存筒仓处为14%。218Po的未附着部分可以直接测量222Rn的浓度。数据表明在储存筒仓处检测到了压力驱动的222Rn气流，并且与通常的222Rn气体测量相比，过滤空气源的测量能力有所增强。有人提出，未附着的218Po的实时测量可用于识别与地震活动相关的压力驱动土壤气流所导致的快速变化的222Rn浓度。
