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

A new microstructure, anode-point based, for the detection of gas ionizing radiations and some preliminary results are presented. For every single detected ionizing radiation it gives a pair of “induced” charges of the same amount (pulses of the same amplitudes), 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 106 with more than 108 electrons in the primary avalanches, working in the proportional region, are possible in 760 Torr of isobutane gas. 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. Single electrons emitted by a heated filament (Ec<1 eV) were detected in 760 Torr of isobutane. With an estimated gas multiplication of 1.2×106 a counting rate up to 800 Kpulse/s was achieved. This microstructure, through the use of the charge pair generated and its mechanical versatility, allows the development of different types of sensitive position two-dimensional read-out detectors.