Main performances of a self-quenching streamer discharge in a wire chamber

The results of the investigation of main performances of self-quenching streamer (SQS) discharge in a wire chamber are presented: amplitude and time performances, chamber counting rate capacity, sensitivity to primary ionization space localization of discharge in a chamber and directivity of streamer development. The investigations have been performed in a single-coordinate multiwire 16x16 cm chamber. The chamber has been blown by the gas mixture of argon, methane and methylal under atmospheric pressure. Main part of measurements has been performed using the gas mixture: 50%Ar+33%CH4+17%(OCH3)2CH2. The analysis of signal amplitude spectra dependence on supply voltage at the chamber irradiation by X ray photons from the 55Fe source shows that at <=3.0 kV voltage in a chamber a proportional mode of gas amplification is observed. With voltage increase the proportionality is distributed, peaks begin to merge. At the 3.4 kV voltage along the pulses, amplitude of which is characteristic for the proportional amplification mode pulses of an essentially larger amplitude begin to appear. The investigation of the effect of primary ionization value on the SQS mode gives the possibility to draw a conclusion that the difference in primary ionization value affects only on supply voltage at which the transition from the proportional to the SQS mode occurs. The SQS mode makes possible effective solution of the problem of removal of left-right ambiguity in drift chambers. The large amplitude of the induced signal in this case gives the possibility to essentially simplify the proper electronic equipment as compared with chambers operating in a proportional mode