The leak microstructure: a novel element for sensitive position two-dimensional read out gaseous detectors. Preliminary results

A new microstructure for the detection of gas ionizing radiations has been characterized. For every-single detected ionizing radiation it gives a pair of "induced" charges of the same amount (pulses of the same amplitude), of opposite sign, with the same collection time and essentially in time coincidence, that are proportional to the primary ionization collected. Gas multiplication more than 10/sup 5/ with more than 10/sup 8/ electrons in the primary avalanches, working in the proportional region, are possible. The complete lack of insulating materials in the active volume of this microstructure avoids problems of charging-up and makes stable and repeatable its behaviour. This microstructure, through the use of the charge pair generated, allows the development of a position sensitive detector with a two-dimensional read-out. Using isobutane as the gas, an energy resolution of about 8% FWHM was recorded with /spl alpha/ particles from an /sup 241/Am source in /spl Delta/E fashion. Always in isobutane gas, X-rays from a /sup 55/Fe source were also detected.