New (TH)GEM coating materials characterised using spectroscopy methods
arXiv:2104.12191 · doi:10.1016/j.nima.2021.165829
Abstract
In this work GEM and single-hole Thick GEM structures, composed of different coating materials, are studied. The used foils incorporate conductive layers made of copper, aluminium, molybdenum, stainless steel, tungsten and tantalum. The main focus of the study is the determination of the material dependence of the formation of electrical discharges in GEM-based detectors. For this task, discharge probability measurements are conducted with several Thick GEM samples using a basic electronics readout chain. In addition to that, optical spectroscopy methods are employed to study the light emitted during discharges from the different foils. It is observed that the light spectra of GEMs include emission lines from the conductive layer material. This indicates the presence of the foil material in the discharge plasma after the initial spark. However, no lines associated with the coating material are observed while studying spark discharges induced in Thick GEMs. It is concluded that the conductive layer material does not play a substantial role in terms of stability against primary discharges. However, a strong material dependence is observed in the case of secondary discharge formation, pointing to molybdenum coating as the one providing increased stability.
arXiv comment11 pages, 13 figures
References in corpus (8)
- Thick GEM-like hole multipliers: properties and possible applications
- The upgrade of the ALICE TPC with GEMs and continuous readout
- Research on discharges in micropattern and small gap gaseous detectors
- Charge density as a driving factor of discharge formation in GEM-based detectors
- Ion mobility measurements in Ar-CO, Ne-CO, and Ne-CO-N mixtures, and the effect of water contents
- Secondary discharge studies in single and multi GEM structures
- Studies of the delayed discharge propagation in the Gas Electron Multiplier (GEM)
- High voltage scheme optimization for secondary discharge mitigation in GEM-based detectors