NEON-BASED GAS-MIXTURES FOR PROPORTIONAL-COUNTERS

Characteristics of gas multiplication and position sensing of Ne- and Ar-based gases have been investigated and compared with each other for position sensitive proportional counters. The measurements were carried out in the high gas multiplication region, i.e. the transition region from the proportional to the self-quenching streamer (SQS) mode. As the quench gas, CH4 and, in some cases, C2H5OH vapor were added with proper mixing proportions. In position sensing, it is advantageous to use gas mixtures which need lower applied anode voltages to obtain high gas multiplication for good S/N ratio. The experimental results suggest that Ne-based gases have advantages in lower anode voltages by about 250 V for 4.5 keV X-rays. It may be concluded that Ne-based gases are useful in the application in which the counter construction is mechanically severe.