Avalanche-ion back-flow reduction in gaseous electron multipliers based on GEM/...

• Author(s): Maia, J. M. ; Mörmann, D. ; Breskin, A. ; Chechik, R. ; Veloso, J. F. C. A. ; Santos, J. M. F. dos
• Date: 2004
• Persistent ID: http://hdl.handle.net/10316/4448
• Origin: Estudo Geral - Universidade de Coimbra
• Subject(s): Gas avalanche electron multipliers; Gaseous photomultipliers; Ion back-flow
• Document Type: Article
• Language: English

Description

We report on avalanche-ion back-flow measurements in the novel Micro-Hole and Strip-Plate (MHSP) multiplier and in gaseous photomultipliers comprising Gas Electron Multipliers (GEMs) followed by an MHSP. In a 3-GEMs/MHSP photomultiplier with reflective photocathode, avalanche-ion back-flow fraction of ~7% and ~2% were recorded for respective effective gains of 107 and 106, in Ar/CH4 (95/5) at 760 Torr. This is about one order of magnitude reduction in ion back-flow compared to the best values measured in 4-GEMs photomultiplier at the same gain. We describe the mode of operation of the MHSP and explain its ion back-flow reduction features. http://www.sciencedirect.com/science/article/B6TJM-4BMBDH7-C/1/cdedfd1e72d3adbcfc9431895ab3e612