Development of a High Resolution TDC Module for the WASA Detector System Based on the GPX ASIC

A high resolution time to digital conversion (TDC) module has been developed for the time-stamping of plastics scintillator signals in the WASA detector system. The module is designed in 6U Eurocard form factor for a proprietary optimized backplane bus with LVDS technology. It provides 64 channels and is based on the GPX ASIC from acam-messelectronic gmbh. In the selected mode the GPX has 8 input channels with a resolution up to 81 ps. Design issues and preliminary results of the performance of the module are discussed.