Development of a High-Resolution Muon Tracking System Based on Micropattern Detectors

A muon tracking system consisting of four 9 cm $\times,$ 10 cm sized bulk Micromegas detectors with 128 $\mu{\rm m}$ amplification-gap and two 10 cm $\times,$ 10 cm triple GEM detectors is foreseen for high-precision tracking of 160 GeV muons at the H8 beamline at CERN with a readout rate above 10 kHz and an overall resolution below 20 $\mu{\rm m}$ . Signal studies of both detector types have been performed by recording cosmic muon and 5.9 keV X-ray signals. The analysis of the complete signal-cycles allows for the determination of rise times, pulse heights, timing fluctuations and discrimination of background, resulting in a FWHM energy resolution of about 20% and detection efficiencies of 98% and more. Models for signal formation in both detector types will be presented. A single detector spatial resolution of 75 $\mu{\rm m}$ was measured for cosmic muons using a fast Gassiplex based strip readout with readout strips of 150 $\mu{\rm m}$ width and a pitch of 250 $\mu{\rm m}$ . Multiple scattering of low energy cosmic muons deteriorates the observable spatial detector resolution by more than 20 $\mu{\rm m}$ . Additionally, we report on the sensitivity to gamma- and neutron background and on the behavior of spatial resolution as a function of background rates.