A new concept for a multi-range low cost calorimeter ADC

The next generation of electromagnetic calorimeters for detectors at colliding beam machines requires an ADC system with characteristics not available today. In this paper, we present a concept for a new ADC system which combines high resolution with the wide dynamic range required by high energy electromagnetic calorimeters. This new ADC can be implemented in either standard rack mounted systems (FASTBUS or 9U VME) or as a complete detector mounted system. This instrument features high density, 12 bits of resolution, 18 bits of dynamic range, excellent linearity and conversion time less than 20 microseconds. The ADC uses multiple Wilkinson charge-to-time conversion circuits to supply the wide dynamic range, and a single time digitizer to measure the run down times for all ranges. The ADC features sparse readout with indication of both the run down time and the range.<>