Low power ADC with fast zero suppression for a balloon-borne experiment

The authors describe a low-power CAMAC analog-to-digital converter (ADC) module with fast zero suppression developed for high-rate data acquisition on a balloon-borne detector. The module incorporates 16 charge-to-voltage converter (QVC) channels in single CAMAC width. Each channel has its individual ADC. Current input signals are digitized simultaneously. Then a microprogrammed sequencer scans the ADC outputs and stores the digitized data when the outputs are greater than prescribed thresholds. The data scan is completed within 18 μs, which depends on the number of hit channels. The QVC circuit was optimized by a simulation program on a workstation in order to reduce the temperature dependence