A Large-Scale Digitizer System (Lsd) for Charge and Time Digitization in High-Energy Physics Experiments

A large-scale digitizer (LSD) system for acquiring charge and time-of-arrival particle data from high-energy-physics experiments has been developed at the Lawrence Berkeley Laboratory. The objective in this development was to significantly reduce the cost of instrumenting large-detector arrays which, for the 4π-geometry of colliding-beam experiments, are proposed with an order of magnitude increase in channel count over previous detectors. In order to achieve the desired economy (~ $65 per channel), a system was designed in which a number of control signals for conversion, for digitization, and for readout are shared in common by all the channels in each 128-channel bin. This paper describes the overall-system concept, and the distribution of control signals that are critical to the 10-bit charge resolution and to the 12-bit time resolution. Also described is the bit-serial transfer scheme, chosen for its low component and cabling costs.