Harley N, Chittaporn P, Medora R, Merrill R
New York University School of Medicine, Department of Environmental Medicine, New York, NY 10016, USA.
Radiat Prot Dosimetry. 2010 Oct;141(4):357-62. doi: 10.1093/rpd/ncq228. Epub 2010 Sep 10.
A miniature four-chamber alpha track detector was developed that measures both (222)Rn (radon) and (220)Rn (thoron), in duplicate. Using this detector and the previous long-term measurements of the (220)Rn decay products (212)Pb, and (212)Bi, an equilibrium factor, F(eq), is derived for both outdoor and indoor (220)Rn environments (0.004±0.001 outdoors and 0.04±0.01 indoors). The lung airway dose can then be calculated from a dose factor from UNSCEAR that requires the equilibrium equivalent thoron concentration (EEC), i.e. the product of F(eq) and the (220)Rn gas concentration. The lung dose from thoron in domestic or occupational surveys is often overlooked. The values of F(eq) for thoron in several published studies are in general agreement with the values reported here. Thus, a long-term alpha track measurement of thoron multiplied by an appropriate indoor or outdoor equilibrium factor yields the EEC, which can be used to assess bronchial lung dose.
研制出了一种微型四腔α径迹探测器，它能对（222）Rn（氡）和（220）Rn（钍射气）进行双重测量。利用该探测器以及之前对（220）Rn衰变产物（212）Pb和（212）Bi的长期测量结果，得出了室外和室内（220）Rn环境的平衡因子F（eq）（室外为0.004±0.001，室内为0.04±0.01）。然后可以根据联合国原子辐射效应科学委员会的剂量因子计算肺部气道剂量，该剂量因子需要平衡当量钍射气浓度（EEC），即F（eq）与（220）Rn气体浓度的乘积。在家庭或职业调查中，钍射气对肺部的剂量往往被忽视。几项已发表研究中钍射气的F（eq）值与本文报道的值总体一致。因此，对钍射气进行长期α径迹测量并乘以适当的室内或室外平衡因子，可得出EEC，用于评估支气管肺部剂量。
