  A muon tracking system consisting of four 9cm x 10cm sized bulk Micromegas
detectors with 128um amplification-gap and two 10cm x 10cm triple GEM detectors
is foreseen for high-precision tracking of 140GeV muons at the H8 beamline at
CERN with a rate of up to 10kHz and an overall resolution below 40um. Larger
detectors with an active area of 0.5m^2 and more are under development for
detector studies in high neutron or gamma ray background environments at the
Gamma Irradiation Facility at CERN and the Munich tandem accelerator. Signal
studies of both detector types have been performed by recording cosmic muon and
5.9keV X-ray signals with a single charge-sensitive preamplifier using several
gas-mixtures of Ar:CO_2. The signals were digitized using 1GHz VME based
flashADCs with 2520 sampling points. 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 99% and more. Models for signal
formation in both detector types will be presented. The single detector spatial
resolution of 80um was measured using a fast Gassiplex based strip readout with
readout strips of 150um width and a pitch of 250um. The Gassiplex readout,
formerly used at the HERMES experiment, had to be substantially adapted. No
more crosstalk or non-linearities were observed after reconfiguration of the
multiplexing amplifier on the frontend boards. The observed spatial resolution
is limited by multiple scattering of the cosmic muons used in the laboratory.
We also report on the sensitivity to gamma- and neutron background and on the
behaviour of spatial resolution as a function of background rates.
