The technique of z-coordinate determination using a time-difference measurement for the ZEUS central tracking detector

A method to determine the z-coordinate of a track using a time-difference measurement has been developed for the ZEUS Central Tracking Detector. It has been demonstrated that a spatial resolution of 50 mm can be obtained under normal chamber operating conditions. This corresponds to a time-difference resolution of 330 ps. A method of minimizing nonlinearities in the time-to-distance response is described. This uses an inductor to form a matching network to achieve resistive termination of the chamber. Test beam measurements from a prototype chamber are presented, demonstrating the effects of the chamber surface field and beam incidence angle on the time-difference resolution. (orig.)