GaAs Microstrip Testbeam Results

TL;DR

This paper reports on testing a GaAs microstrip detector with high-energy pions, achieving near-expected resolution, but noise limited performance and detection efficiency, with ongoing investigation into noise sources.

Contribution

Introduction of a GaAs detector with a novel biasing scheme and detailed performance evaluation under high-energy pion beam conditions.

Findings

Measured resolution of ~14μm, improved to ~12μm with charge division.

Noise was significantly higher than expected, affecting resolution and efficiency.

Detection efficiency was reduced due to excess noise, source under investigation.

Abstract

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.