摘要
利用气土子体ThC'衰变产生的α粒子能量较氡及其子体衰变产生的α粒子能量高的特点,发展了一种测量介质表面气土析出率的方法。描述了加吸收体甄别氡及进行气土析出率直接测量的原理,研制了被动积分测气土析出率计。测气土析出率计的刻度系数R=0 246cm-2·(kBq·m-3·h)-1,当测量周期为7d、所用CR 39固体核径迹探测器本底径迹密度标准差sT=1 6cm-2时,其测气土析出率的探测下限LLD=18 4mBq·m-2·s-1。
A measurement method of thoron exhalation rate is developed based on the characteristic of thorium C' which emits a α particle with higher energy than those of α particles released from radon and radon progenies. The principles of discriminating radon and realizing thoron exhalation rate measurement on the material surface with absorber, the passive and integrated thoron exhalation rate monitor studied, and its calibration coefficent determination method are introduced. The effectiveness of mitigating thoron exhalation rate of wall surface by depresurization inside wall and thoron exhalation rates on some materials surfaces were measured by using the studied monitors. The calibration coefficient of the studied monitor is R=0246 cm-2·(kBq·m-3·h)-1, The lower limit of detection is LLD=184 mBq·m-2·s-1 when the sampling period is 7 days and the standard deviation of background track densities of the adopted CR39 SSNTD is sT=16 cm-2.
出处
《原子能科学技术》
EI
CAS
CSCD
2003年第5期476-480,共5页
Atomic Energy Science and Technology
基金
国家自然科学基金资助项目(10075083)
