Muramatsu H, Hasegawa N, Misawa C, Minami M, Tanaka E, Asami K, Kuroda C, Kawakami A
Department of Chemistry, Faculty of Education, Shinshu University, Nishinagano, Nagano, Japan.
Health Phys. 1999 Jul;77(1):43-51. doi: 10.1097/00004032-199907000-00009.
The survey of 222Rn concentration in the air of tunnels constructed during World War II has been performed using a solid-state nuclear track detector technique. For the practical application of this technique to the determination of 222Rn concentrations in air, some basic properties were experimentally examined on the cellulose nitrate film, Kodak LR 115 type II. The calibration coefficient of the cellulose nitrate film used is determined from a correlation between the 222Rn concentration in air and the observed number of perforated etched tracks for widespread radon concentrations. The slope of the linear relationship observed yields a calibration coefficient of (0.00209 +/- 0.00018) tracks cm(-2) (Bq m(-3) h)(-1). From the survey of 222Rn concentration in the air of tunnels, the concentration of several thousand Bq m(-3) was observed at the inner most area of the tunnel, and the seasonal variation was clearly observed. The exponential distribution of radon concentration as a function of distance from the openings of the tunnel suggests that the radon concentration in the tunnel is basically governed by diffusion and mixing of radon gas with air.
利用固态核径迹探测器技术对第二次世界大战期间建造的隧道空气中的222Rn浓度进行了调查。为了将该技术实际应用于空气中222Rn浓度的测定，对柯达LR 115 II型硝酸纤维素膜的一些基本特性进行了实验研究。所用硝酸纤维素膜的校准系数是根据空气中222Rn浓度与广泛的氡浓度下观察到的穿孔蚀刻径迹数量之间的相关性确定的。观察到的线性关系的斜率得出校准系数为(0.00209±0.00018) 径迹·厘米-2·(贝克勒尔·米-3·小时)-1。通过对隧道空气中222Rn浓度的调查，在隧道最内部区域观察到数千贝克勒尔·米-3的浓度，并且明显观察到了季节变化。氡浓度随离隧道开口距离的指数分布表明，隧道中的氡浓度基本上受氡气与空气的扩散和混合控制。
