Progress in the development of the DTMROC time measurement chip for the ATLAS Transition Radiation Tracker (TRT)

A 16-channel digital time-measurement readout chip (DTMROC) has been fabricated in the TEMIC/DMILL BI-CMOS radiation-hard process for the Large Hadron Collider (LHC) Transition Radiation Tracker (ATLAS/TRT) at CERN. The chip receives discriminated straw-drift-tube signals from bipolar amplifier-shaper-discriminator chips (ASDBLR), measures the arrival time in 3.125 ns increments (/spl plusmn/1 ns), and stores the data in a pipeline for 3.3 /spl mu/s. A trigger signal (L1A) causes the data to be tagged with a time stamp and stored for readout. Up to 13 events may be stored in an on-chip buffer while data is being clocked out in a 40 MHz serial stream. The chip has been designed to function after exposure to 1/spl times/10/sup 14/ protons/cm/sup 2/ and 1 Mrad total dose. System beam-tests have demonstrated measurement of track positions with a resolution of 165 /spl mu/m and 85% efficiency at rates up to 18 MHz.