The High Momentum Spectrometer drift chambers in Hall C at CEBAF

The multiwire drift chambers to be used in the High Momentum Spectrometer (HMS) at the Continuous Electron Beam Accelerator Facility (CEBAF) have been designed and constructed, and recently employed in initial data-taking runs. These chambers are used to reconstruct scattered charged particle momenta in the HMS using C-12 and BeO2 targets for incident electron energies up to 2.2 GeV. Offline analysis of the data indicate that these drift chambers have spatial resolution (per plane) of about 115 mu m (sigma) in rates approaching a kHz/wire/mm. It is expected that this performance will improve at higher momenta where multiple scattering contributions are smaller.