GaAs microstrip test beam results

A gallium arsenide detector was tested with a beam of 70GeV pions at the {\sf SPS} at CERN. The detector utilises a novel biasing scheme which has been shown to behave as expected. The detector has a pitch of 50\mum and therefore an expected resolution of 14.5\mum. The measured resolution was approximately 14\mum. By using a non-linear charge division algorithm this can be increased to \approx 12\mum. Noise was the limiting factor to the resolution. This was 2000e^- as opposed to the expected 360e^-. This noise is also thought to have reduced the detection efficiency of the detector. The source of the excess noise is currently being investigated.