Sporadic electron jets from cathodes - The main breakdown-triggering mechanism in gaseous detectors
2002 (English)In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 49, no 4, 1622-1628 p.Article in journal (Refereed) Published
We have demonstrated experimentally that the main breakdown-triggering mechanism in most gaseous detectors, including micropattern gaseous detectors, is sporadic electron jets from the cathode surfaces. Depending on the counting rate and applied voltages, each jet contains randomly from a few primary electrons up to 10(5), emitted in a time interval ranging between 0.1 mus to milliseconds. After the emission, these primary electrons experience a full gas multiplication in the detector and create spurious pulses. The rate of these jets increases with applied voltage and very sharply at voltages close to the breakdown limit. In our measurements, we found that these jets are responsible for the breakdown-triggering at any counting rate between 10(-2) Hz/mm(2) and 10(8) Hz/mm(2). We demonstrated on a few detectors that an optimized cathode-geometry, a high electrode surface quality, and a proper choice of the gas mixture considerably improve the performance characteristics and provide the highest possible gains. Results from this work were helpful in the construction of high-performance gaseous detectors for medical imaging applications.
Place, publisher, year, edition, pages
2002. Vol. 49, no 4, 1622-1628 p.
breakdown, gaseous detectors, GEM, RPC, high-rate behavior, chambers
IdentifiersURN: urn:nbn:se:kth:diva-22011ISI: 000178951100006OAI: oai:DiVA.org:kth-22011DiVA: diva2:340709
QC 201005252010-08-102010-08-10Bibliographically approved