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一、引言对于低能量和低放射性水平的气体,最有效的探测方法是使用充气计数管,即将欲测之放射性气体作为气体组分的一部分充到计数管中,这样气体与电极之间没有隔层,距离也缩短,因而计数效率最高,对低水平的、弱的射线的测量可以大大提高灵敏度。很久以前使用充气计数管测量天然间氚(H~3)的自然分布获得了成功,虽然氚的β能量很弱,只有0.01795兆电子伏特。后来Fergusson G.,J.Williams等人使用正比充气计数管,在大气压力下测量乙炔和二氧化碳等弱放射性物质,灵敏度很高。
I. INTRODUCTION For low-energy and low-level gases, the most effective method of detection is to use a gas-filled counter tube that will fill the counter-tube with the radioactive gas to be measured as part of the gas composition so that there is no separation between gas and electrode Layer, the distance is also shortened, and thus the highest counting efficiency, low level, weak ray measurement can greatly improve the sensitivity. The natural distribution of natural tritium (H ~ 3) was measured long ago by the use of an inflatable counter tube, although the beta energy of tritium is very weak at 0.01795 MeV. Later, Fergusson G., J. Williams, et al. Used proportional inflation tubes to measure weak radioactive materials such as acetylene and carbon dioxide at atmospheric pressure with high sensitivity.