Tokonami S, Ichiji T, Iimoto T, Kurosawa R
Division of Environmental Health, National Institute of Radiological Sciences, Chiba, Japan.
Health Phys. 1996 Dec;71(6):937-43. doi: 10.1097/00004032-199612000-00010.
A continuous potential alpha energy concentration monitor was developed to estimate the lung dose for inhalation of radon progeny. A silicon semiconductor detector was used as a detector. The build-up method was used and alpha particles emitted from 218Po, 214Po, 212Bi, and 212Po were detected. As 218Po and 212Bi have alpha particles of nearly the same energy, three detecting channels were set up. Counts corresponding to each nuclide were sent to a printer every 30 min. For the purpose of determining the potential alpha energy concentration of radon progeny continuously, a proper calculation procedure was investigated in detail. With this method, 218Po concentration and potential alpha energy concentration of radon progeny could be continuously obtained. The potential alpha energy concentration based on this procedure agreed well with that calculated from individual radon progeny concentration. When the measurement was done at 30-min intervals, the minimum detectable concentrations of 218Po concentration and equilibrium equivalent radon concentration were 0.3 Bq m(-3) and 0.15 Bq m(-3), respectively. The monitor can be used not only to estimate the lung dose but also to analyze environmental behavior of radon progeny.
为估算吸入氡子体所致的肺部剂量，研制了一种连续潜在α能量浓度监测仪。该监测仪采用硅半导体探测器作为探测器，运用积累法对²¹⁸Po、²¹⁴Po、²¹²Bi和²¹²Po发射的α粒子进行探测。由于²¹⁸Po和²¹²Bi的α粒子能量相近，因此设置了三个探测通道。每隔30分钟将各核素对应的计数发送至打印机。为了连续测定氡子体的潜在α能量浓度，详细研究了一种合适的计算程序。通过该方法，可连续获取²¹⁸Po浓度和氡子体的潜在α能量浓度。基于此程序得到的潜在α能量浓度与根据单个氡子体浓度计算得到的结果吻合良好。当以30分钟为间隔进行测量时，²¹⁸Po浓度和平衡当量氡浓度的最低可探测浓度分别为0.3 Bq m⁻³和0.15 Bq m⁻³。该监测仪不仅可用于估算肺部剂量，还可用于分析氡子体的环境行为。
