THE LEAK MICROSTRUCTURE - A NOVEL ELEMENT FOR SENSITIVE POSITION 2-DIMENSIONAL READOUT GASEOUS DETECTORS - PRELIMINARY-RESULTS

A new microstructure, anode-point based, for the detection of gas ioni zing radiations and some preliminary results are presented. For every single detected ionizing radiation it gives a pair of ''induced'' char ges of the same amount (pulses of the same amplitudes), of opposite si gn, with the same collection time and essentially in time coincidence, that are proportional to the primary ionization collected. Gas multip lication more than 10(6) with more than 10(8) electrons in the primary avalanches, working in the proportional region, are possible in 760 T orr of isobutane gas. The complete lack of insulating materials in the active volume of this microstructure avoids problems of charging-up a nd makes stable and repeatable its behaviour. Single electrons emitted by a heated filament (E-c < 1 eV) were detected in 760 Torr of isobut ane. With an estimated gas multiplication of 1.2 x 10(6) a counting ra te up to 800 Kpulse/s was achieved. This microstructure, through the u se of the charge pair generated and its mechanical versatility, allows the development of different types of sensitive position two-dimensio nal read-out detectors. (C) 1998 Elsevier Science B.V. All rights rese rved.