Design and performance of a silicon test counter for HERMES

A small silicon-detector array has been designed and constructed to investigate the prospects for large-angle tracking and detection of recoiling target fragments for the HERMES experiment at DESY in Hamburg, Germany. The array consists of a two-layered double-sided Silicon Test Counter (STC), which is used to study the feasibility of this technique. The STC has been installed below the center of the HERMES internal storage cell target inside the vacuum chamber, and is thus located in the vicinity of the high-intensity lepton beam of HERA. For the readout, a local front-end with 64-channel Analog Pipeline Chips (APC) has been employed. The large dynamic range of the APC allows for the identification and tracking of protons with momenta ranging from 100 to 600MeV/c. The feasibility of the detector concept is shown, thus demonstrating that a multilayer silicon system can be used for the observation of recoiling protons produced in Deep Inelastic Scattering (DIS).