Construction and performance of a micro-pattern stereo detector with two gas electron multipliers [online]

The construction of a micro-pattern gas detector of dimensions 40 x 10 cm² is described. Two gas electron multiplier foils (GEM) provide the internal amplification stages. A two-layer readout structure was used, manufactured in the same technology as the GEM foils. The strips of each layer cross at an effective crossing angle of 6.7 degrees and have a 406 micro-m pitch. The performance of the detector has been evaluated in a muon beam at CERN using a silicon telescope as reference system. The position resolutions of two orthogonal coordinates are measured to be 50 micro-m and 1 mm, respectively. The muon detection efficiency for two-dimensional space points reaches 96%. Key words: detector, position sensitive, GEM, two-layer readou

Performance test of a micro-pattern stereo detector with two gas electron multipliers [online]

We report on the performance of a large micro-pattern detector with two gas electron multiplier foils (GEM) and a two-layer readout structure at ground potential. The two readout layers each have a 406 micro-m pitch and cross at an effective angle of 6.7 degrees. This structure allows for two orthogonal coordinates to be determined. Using a muon beam at CERN together with a silicon tracking system, the position resolutions of the two coordinates are measured to be 50 micro-m and 1 mm respectively (1 stand.dev.). The muon detection efficiency for the two-dimensional space points reaches 96%. The detector was found to be well operational over a wide range in the settings of the different electrical fields

Tests of CMS MSGC Modules at PSI

The CMS experiment, to be installed at the future p-p collider LHC at CERN, foresees the use of Micro-Strip Gas Counters ( MSGC's) for the outer layers of its central tracker. Present developments focus on the reliability of MSGC's in the harsh radiation environment imposed by the LHC. This paper reports on tests of two baseline CMS MSGC's identical to those foreseen for the barrel part of the tracker, in a high intensity pion beam at the Paul Scherrer Institute ( PSI), in april 1999