Test results from a precision drift chamber vertex detector prototype using dimethyl ether

Results of beam tests of a prototype drift chamber vertex detector developed for the D-Zero experiment at the Fermilab collider are reported. The chamber design emphasizes dual goals of high accuracy position measurement and excellent two track resolution. These requirements are met by using a slow gas, dimethyl ether, in a jet chamber geometry with a double plane of field-shaping wires near the anodes. Resolution of nearby hits is faciliated by 100 MHz flash digitization of the signal pulses. The prototype tested consisted of a full-lenght (97 cm) model of one azimuthal sector of the innermost layer of the detector, with 8 anode wires. Position measurement accuracy of 30-80 μm for drift distances of 2-11 mm and pulse pair resolution of 0,7 mm (for 90% of all pulses) is achieved. (orig.)