GaAs Microstrip Testbeam 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$\mu$m and therefore an expected resolution of 14.5$\mu$m. The measured resolution was approximately 14$\mu$m. By using a non-linear charge division algorithm this can be increased to $\approx$ 12$\mu$m. 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.