Optical observation of self-quenching streamers by /spl alpha/- and /spl beta/-rays

Optical images of self-quenching streamers (SQSs) in a gas counter have been observed for /spl alpha/- and /spl beta/-rays, incident charged particles. Individual images of the streamers were obtained by using an image-intensifier system with a gating function. The observation was performed from the axial direction of the gas counter used. For /spl alpha/-ray irradiation, streamers develop only in two specific directions orienting primary-ionization tracks formed by /spl alpha/-rays. On the other hand, for /spl beta/-ray, streamers grow in various directions; obtained images are similar to those for X-rays. On the basis of the observation, SQS-formation mechanisms by different sorts of ionizing radiation are discussed. A possible mechanism of "primary-ionization track oriented (PRITOR) type SQS" induced by /spl alpha/-rays is proposed.<
>