Data Acquisition system for in-beam detector characterisation run using Cologne accelerator.
64 channels of GRT4 electronics (16 cards) were used, each collecting a trace (1k bytes) whenever there was a trigger from the CFD on the core contact of either detector. The Trigger was fanned out to all cards using a NIM logic fan-out unit. The GRT4 cards were configured to generate a “busy out” signal when their buffers were full. These 16 busy signals were connected to a NIM logic fan-in and used to prevent new triggers until all 16 cards had room in their buffers. In this way all cards were synchronised. The VME processor polled all the GRT4 FIFO buffers waiting for data, and read what was available, checking the correlation using the event number field in the data. Total readout rate through the whole system to tape was over 7500 traces/second (i.e. 120 events/second or 7.7Mbytes/sec) shared between the 2 crates.