In the present study, thoron exhalation flux density were measured in the soil samples collected around the Indian station namely Bharati (69° 24.41' S, 76° 11.72' E) and its nearby islands in the Larsemann hills region of Antarctica. Further, dependency of thoron mass emanation rate and emanation coefficient on the soil grain size was studied by segregating the soil samples into four different grain size groups: 50-100 μm, 100-200 μm, 200-500 μm and 500-1000 μm which showed that both of them follow a decreasing trend with increase in grain size. A comparison of measured mass emanation rate between different soil samples showed that it had a larger variation for the smaller grain size which eventually decreased as grain size increased while emanation coefficient was observed to be nearly constant for all the grain size groups. The variation in emanation coefficient with respect to mean grain size has been investigated and an empirical exponential model has been proposed for predicting emanation coefficient for different grain sizes.

中文翻译：

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南极拉尔瑟曼山地区土壤样品中220Rn释放和呼出的调查。

在本研究中，在印度站即巴拉特（南纬69°24.41'，东经76°11.72'）及其附近岛屿在南极的拉瑟曼山地区附近收集的土壤样品中，测量了ron气呼出通量密度。此外，通过将土壤样品分成四个不同的粒度组：50-100μm，100-200μm，200-500μm和500-1000μm，研究了ron质散发速率和散发系数对土壤粒度的依赖性。结果表明，随着晶粒尺寸的增加，它们都遵循减小的趋势。对不同土壤样品之间测得的质量散发率的比较表明，对于较小的粒径，散发率变化较大，最终随粒径增加而减小，而对于所有粒径组，散发系数几乎恒定。