1. High-Resolution Micromegas Telescope for Pion- and Muon-Tracking
J. Bortfeldt et al. – LMU Munich
goal: track reference system with <20μm track resolution for detector tests with high-energy pions and muons
4 Micromegas detectors
9cm x 10cm active area, 360 copper strips, 250μm pitch
gas: Ar:CO2 1013mbar
segmented trigger scintillators → 3rd track coordinate
readout: Gassiplex based frontend modules, 1500 channels in total
synchronization with other DAQ systems via external 12 bit trigger counter → 12ch TDC
detector calibration using 160GeV pions at the H6 SPS, CERN

2. High-Resolution Micromegas Telescope for Pion- and Muon-Tracking
J. Bortfeldt et al. – LMU Munich
best value of efficiency: 98.5% (fully efficient)
discharge probability: 1.5 x 10-5 per pion → 0.66% dead 22kHz particle rate → negligible
best value of single detector spatial resolution: 35μm → track resolution <20μm with 2 x 2 detectors
only weak influence of gas gain and diffusion on spatial resolution
spatial resolution depends on number of primary electrons, reaching the amplification region