OWG meeting 11-Apr-2008

Agenda

• Announcements
• Review of minutes from 4-Apr-2008 meeting
• Event size study - Alex S.
• Pre-brief outlines for May 2008 Subsystem Review - many people
• Progress towards subsystem review - many people

Time/Location

2pm Fri 11-Apr-2008 CC F326

Announcements

Subsystem review likely Wed,Thurs 7,8-May.

Elke's Deadlines

• Final presentations to Elke: 5-May close-of-business
• Pre-brief material to reviewers: 30-April
• Pre-brief material to Hall-D group to read: 23-April
• Pre-brief outlines: 11-April

Next Meeting

2pm Fri 18-Apr-2008 CC F326

Minutes

Attendees: Elliott W, Simon T, Elton S, Alex S, Fernando B, Mark I, Dave D, Chris C, Jim S, Eugene C.

Admin has approved two new sorely-needed hires for the JLab DAQ group. Both will focus on hardware. One will work with Dave A, the other will work with Ed J.

Event Size Study - Alex S

• See Alex's slides via link above.
• David L out of town for this meeting, everything needs to be compared to his original results.
• Studied rates and occupancies in all detectors.
• Included EM background (100 ns gate) from Geant3.
• Included hadronic signal and background from Pythia (Eugene's version).
• Used simple trigger cuts (e.g. FCAL E>0.4 GeV), will redo using strategy from CNU Genetic Algorithm study.
• 400 kHz hadronic rate at 10**8 photons/sec, L1 divide by 2 to 200 kHz, L3 divide by 10 to 20 kHz.
• EM supplies major background, more than hadronic.
• Advantage to tighten gates used in trigger to minimize EM background (Alex used 100 ns).
• 10**8 tagged photons corresponds to about 3 10**8 in tagger, collimator removes about factor of 3.
• Average number of hits in each detector in rough agreement with Dave L's results.
• Most hits in FDC, 475 per event, of which 269 is due to EM background. Cuts are photon energy > 8 Gev, FCAL energy > 0.4 GeV
• Most detectors hit count dominated by EM.
• Some questions about photon cutoffs in simulation need to be resolved.
• 100 ns may be too large a gate width.
• Optimization needed: tighter gates may allow looser trigger, since events cleaned up
• Alex will report again at the next meeting, will include summary tables, use CNU trigger algorithm, etc.
• Need to estimate bytes-per-hit for each detector to get final average event size.

May 2008 Subsystem Review

• Charge, agenda, and reviewers not final yet.
• Outlines for pre-brief (due today) mostly done, see review page.
• Electronics needs overview doc (Fernando will do this), otherwise coming along well.
• Trigger needs outline (Alex will make first draft).
• DAQ in good shape, most writing assignments done, Graham will edit and write overview doc.
• Preliminary integration/monitoring/controls outline done, writing to start next week.