本研究的主要目的是設計反符合比例計數器以度量環境中低階的氪－85。研究結果顯示對於氪－85的687keV最大β(上標 -)能量，儀器的計數效率爲5.78%，最小偵測活度爲1.93Bq。移動式系統的回收率爲91.6%，計數與採樣系統最低偵測極限爲3.56Bqm^(-3)，此改良的系統非常適用於環境中及低濃度氪－85的監測。

An anticoincidence proportional counter has been developed for measuring low-level 8SKr concentrations in ambient air. The minimum detectable activity is 1.93 Bq. and the counting efficiency is 5.78% based on the 687 keV β(superscript -) maximum energy of 85Kr. The recovery yield of the portable sampling system used was 91.6%. The lower limit of detection of this counting system and sampling was 3.56 Bq m^(-3). This improved system is very suitable for monitoring ultra-low level 85Kr concentrations in ambient air.