Count-loss mechanism of self-quenching streamer (SQS) tubes

The counting response of SQS tubes is superior to that of conventional GM tubes. The count-loss mechanism of SQS tubes is governed by two different sorts of the space-charge effect, namely a local space-charge effect and a global space-charge effect. The existence of a dead zone leads to the local space-charge effect around each streamer; this effect is dominant at lower exposure rate conditions than 20 mR/h. On the other hand, the global space-charge effect comes from accumulation of slowly-drifting positive ions inside the whole tube, and is dominant at higher exposure-rate conditions than 500 mR/h. (orig.)