EVALUATION OF THE INITIAL ANGULAR WIDTH OF THE AVALANCHE IN A PROPORTIONAL CHAMBER

Experimental measurements have been made of the ratio of the signals induced on the cathodes of a symmetric multi-wire proportional chamber under X-ray irradiation. Because of avalanche angular localisation this ratio depends strongly on the lateral position of the X-ray beam. It is shown how a simple theoretical model may be employed with these measurements to evaluate the width of the initial angular distribution of the positive ions in the avalanche. © 1979.