A/D processing system for 64-element pixel detector

A new, 8/spl times/8-element pixel detector array for time resolved protein crystallography has been developed at the Lawrence Berkeley National Laboratory (LBNL). Each element has its own on-chip charge sensitive preamplifier and shaper with a peaking time of 100 ns. A total of 64 parallel analog to digital processing channels are required to support the detector. We describe a low-cost, low-power AD processing system, comprising a fast peak-sensing amplifier/stretcher, followed by a slower 12-bit ADC. Each channel also includes a histogramming memory for a fully stand-alone operation of the system. Circuit performance and test data are also presented.