Position sensitive proportional counter based on the asymmetry of electron avalanche

The characteristics of a multi-wire proportional counter, which will be set at the focal plane of the small X-ray reflecting telescope mounted on the Astro-B, were studied. The proportional counter has 13 front wires as well as the wires for anti-coincidence. Among the front wires, inner seven wires (the wires No. 4 to 10) are used for taking signals out. The sixth wire was irradiated by collimated X-ray, and the output signals from the sixth and seventh wires were observed. It was found that the position of the X-ray incidence was able to be determined with the accuracy of one-tenth of the wire gap. (Kato, T.)