DVCS-Hodoscope trigger system design 19-Oct-2007

I'm thinking the easiest test can be the done following way:

We can setup the system with the discriminators all tied to the same load (i.e. use a fanout device where ultimately a single input can be fanned out to all discriminators). We can then create test patterns by using a pulser to drive the single input of the fanout to the discriminators. Then we can create any cluster pattern by setting the discriminator thresholds low so they're triggered by the pulser. Since the discriminator thresholds are real-time progrmamable over VME I can have a program read hit patterns from a file and setup the discriminators and then record for which events the system finds a trigger.

This would test the trigger at the full-speed (though events won't be generated at full speed they will be processed at full speed)...Of course we'll need several fan-out units (15x 1->32 ECL fanout boards: 1->32->448) and a bunch of LEMO cables (but you'll need those in the end anyway).

If this doesn't sound feasible we can elect to do a simpler setup, but it would be wise to test the entire setup.

For the Hodoscope: If all the detectors in one quadrant of the tower calorimeter can depend on no more than 32 elements of the hodoscope (say for an 80 element hodoscope, 20 elements will go to each quadrant of the calorimeter + 12 more for shared edges = 32 inputs). If this setup works, then we can use 2 additional V1495 boards. Both outputs from the hodoscope discriminators would feed each extra V1495 board using 3x 32b input ports on each. Then each V1495 (connected to Hodoscope discriminators) can feed 2 quadrants of the tower calorimeter V1495 boards.

I can update the drawing showing this setup.

Ben