256 Channel Data Acquisition System for VISTA Focal Plane to Readout Sixteen 2K×K Raytheon VIRGO Detectors

The ESO standard Infrared Array Control Electronics, IRACE, is used to read out the VISTA focal plane, which contains sixteen 2k x 2k VIRGO detectors. Each detector has 16 parallel video output channels. In total 256 video channels have to be processed resulting in a readout time for the complete focal plane of less than 1 sec. The IRACE system is modular and can be adapted for VISTA. It contains 27 VME size boards, which are distributed in three separate VME crates, Sixteen boards are ADC boards each board accommodating 16 video channels. All three boxes are connected by digital isolated differential signal cables to avoid any timing jitter and to trigger all of ADC’s simultaneously. An additional module had to be designed, which uses digital isolators to distribute the main signals like system clock, trigger pulse, reset signal and status bus control signals. The number cruncher of the data acquisition system needed for data capturing and preprocessing is realized by three high speed Linux-PC’s with dual 3 GHz CPU’s