Minutes 060609
From GlueXWiki
Notes for item 2, tagger and trigger timing, etc:
1. We should install He bags; need official request to H-B for this and other beamline components incl. radiator thickness, collimator size, etc.
2. Tagger trigger timing (thanks to Eugene Pasyuk): 20 ns transit time in PMT's 50 ns cable to CFD 10-15 ns internal CFD 5 ns cable to L-R coincidence module 5 ns internal coincidence module 10 ns cable to Master OR module 20 ns internal Master OR 80 ns cable to forward carriage ----- 200 ns Note that photon flight time to alcove is approx 100 ns. If I recall, Richard said RadPhi has both 250 ns cables and 80 ns cables running from the alcove to the RadPhi racks.
3. Tagger uses LeCroy 1877 multi-hit and CAEN pipelined TDC's; both run in common-stop mode
4. CAEN V792 ADC (BCAL readout) is slowest and sets front-end busy time. May skip busy and just use front-end-busy-timer in TS, as V792 has fixed digitization time of approx 7 microsec.