S. Ito et al., BEHAVIOR OF THE SQS MODE OBSERVED AS A FUNCTION OF THE RADIAL DISTANCE OF THE POSITION OF PRIMARY IONIZATION, Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment, 329(3), 1993, pp. 564-566
In the transition region from proportional to the self-quenching strea
mer (SQS) mode in Ar + 30% CH4 gas mixture, the degree of gas amplific
ation and the transition probability to the SQS mode have been studied
as a function of r, where r is defined as the radial distance between
the position of primary ionization and the anode wire. It is found fo
r the first time that an enhancement of the SQS transition occurs for
small r in the vicinity of the anode wire, however, the degree of gas
amplification for the SQS mode is independent of r. The results may in
dicate that the structural change of primary-electron cloud caused by
the diffusion effect influences the transition probability from propor
tional to SQS mode.