Construction of the CLEOIII tracking system: Silicon vertex detector and drift chamber

The CLEO III group is constructing a tracking system (4-layer silicon vertex detector and 47-layer central drift chamber) to be compatible with the interaction region to be installed as part of the staged luminosity upgrade program at the Cornell Electron Storage Ring. Compared to CLEO II, the double-sided silicon detector will have improved signal-to-noise due to long integration times and improvements in the p-type implant barrier on the n-type side. Diamond beams will provide a low mass rigid support system. Although having less radial extent than the current CLEO II tracking system, CLEO III will have equivalent momentum resolution because of material reduction in the drift chamber inner wall and gas. Helium based gas provides further improvements in the spatial resolution.