Karlsruhe 2011 – scientific programme

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T: Fachverband Teilchenphysik

T 70: Myondetektoren II

T 70.6: Talk

Thursday, March 31, 2011, 18:00–18:15, 30.23: 2-11

Development of High-Resolution GEM-Based Gaseous Detectors — •David Heereman, Otmar Biebel, Jonathan Bortfeldt, and Ralf Hertenberger — LS Schaile, LMU München

We report on the development of triple GEM detectors of 10 × 10 cm² standard size. They are foreseen as muon track monitors at the H8 beam line at CERN. Spatial resolution better than 50 µm is envisaged for 140 GeV muons. Four versions of the detector are built and tested: one with an unsegmented anode, one with a five-fold segmented anode, one version with 360 anode strips of 150 µm width and of 250 µm pitch to be read out by GASSIPLEX frontends and a similar device with 384 strips to be read out by APV25 frontends. All versions were investigated using Ar/CO₂ gas at a ratio of 93/7. Stable operation over several days was observed. 5.9 keV X-rays from a ⁵⁵Fe source and cosmic muons are used to investigate and characterize signal formation and rise time achieving an energy resolution of 18% FWHM and efficiencies above 95%. First measurements with the GASSIPLEX readout system show a spatial resolution of approximately 80 µ m that is limited by multiple scattering of the cosmic muons. The readout chain for the APV25 based frontends is designed and the production of the frontend modules is finished. Detectors with larger active areas around 0.5 m² are planned for use under intense n or γ irradiation.