Devices for Detecting and Tracing the Paths of Ionizing Particles

摘要

The performance of spark chambers traversed by heavily ionizing alpha particles from polonium-210 was studied. Bright sparks along the alpha particle tracks were readily obtained up to about 60 degrees with the normal to the electrodes. The densely packed ion-pairs favor the overlapping of the electron avalanches, thereby making it possible for the spark to follow the particle up to wide angles. Experiments were made showing that the addition of 0.1 percent or less of SF6 very greatly reduced the lifetime of the free electrons initiating the electron avalanches. (Author)