D0 vertex drift chamber construction and test results

A jet-cell based vertex chamber has been built for the D0 experiment at Fermilab and operated in a test beam there. Low drift velocity and diffusion properties were achieved using CO2(95%)-ethane(5%) at atmospheric pressure. The drift velocity is found to be consistent with [9.74+8.68(vertical strokeEvertical stroke-1.25)vertical strokeμm/ns where E is the electric field strength in kV/cm (1.0 kV/cm<vertical strokeEvertical stroke<1.6 kV/cm). An intrinsic spatial resolution of 60 μm or better for drift distances greater than 2 mm is measured. The track pair efficiency is estimated to be better than 90% for separations greater than 630 μm. (orig.)