VXI Readout

Eurogam I and Eurogam II used "Common Dead-Time" mode VXI readout. This means that all the electronics remained disabled while an event was being digitized by the adcs and the data read from each card active in the event by the crate ROCO. Apart from being simple this mode also ensured that there was no other activity in the crate during the analogue processing stages within the VXI cards. At the time the Eurogam I VXI cards were being designed this was a sensible precaution.

Euroball will use a "parallel" mode in which only the VXI cards (detector channels) active in an event will be disabled and then only until the data is in a FIFO ready for VXI readout. All other cards will be reenabled as soon as it is determined that they have no part in the current event.

The Eurogam I cards cannot be made to operate in this parallel mode and so 2 pairs of cards only will be installed in a VXI crate (total 3 crates) and the crate be treated as a unit in parallel readout mode. For later phases of Euroball the Eurogam I cards will be redesigned.