Recent results obtained with a gaseous microstrip detector Micromegas devel
oped for the tracking in the high-rate environment of the COMPASS experimen
t at CERN are presented. A 26 x 36cm(2) prototype equipped with the low-noi
se preamplifier SFE16 was tested in a high-energy hadron beam at CERN. With
a gas mixture based on neon, the full efficiency of tile Micromegas protot
ype is obtained at a gain of 6400; the spatial resolution is 50 mum and the
time jitter 8.5 ns. We have studied the problem of discharges that affect
this kind of microstrip detector, and found that, at fixed gain, the probab
ility of discharge is higher for heavier gas mixtures in the detector. In t
he conditions of the COMPASS experiment, discharges are kept at a low rate.
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