Greiner N R
Health Phys. 1985 Mar;48(3):283-8. doi: 10.1097/00004032-198503000-00004.
The emanation of 222Rn from several coal samples (including lignites) was measured as a function of particle size and water content. From 10 to 0.85 mm, particle diameter had no measurable effect on 222Rn emanation. However, the fraction of 222Rn emanated did have a linear dependence on water content, the upper limit observed being equal to the weight fraction of water in the coal. Coals and lignites having typical concentrations of 238U emanate no more 222Rn than do comparable masses of typical soils. Our results appear to have implications for the spatial relationship between the 226Ra atoms and the pores in the coals on the scale of the 222Rn recoil range (0.05 micron).
测量了几种煤样（包括褐煤）中222Rn的析出率与颗粒大小和含水量的关系。在粒径从10毫米到0.85毫米范围内，粒径对222Rn的析出没有可测量的影响。然而，222Rn的析出率与含水量呈线性关系，观察到的上限等于煤中水分的重量分数。具有典型238U浓度的煤和褐煤析出的222Rn并不比同等质量的典型土壤多。我们的结果似乎对226Ra原子与煤中孔隙在222Rn反冲范围（0.05微米）尺度上的空间关系有影响。
