A HIGH-RESOLUTION TDC SUBSYSTEM

A high resolution TDC subsystem was developed at the Institute for Nuc lear Physics in Mainz. The TDC chip offers a time resolution of less t han 300ps and a programmable measurement range from 0 to 16musec. The time measurement is done with a new, purely digital counting methode. The chip can be operated in common start or common stop mode. In commo n start mode the chip is able to store up to 4 multiple hits per chann el. The chip is used to build a transputer controlled subsystem for th e measurement of the drift times of a vertical drift chamber. The desi gn of the subsystem will be described and the first results from the t ests of the prototype system will be presented.