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 (approximately $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. 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 are described. Also described is the bit-serial transfer scheme, chosen for its low component and cabling costs