Notes on the Engineering Model - 03/27/01

Martin Nordby is working under the assumption that the Engineering Model has

• 3 instrumented silicon trays (TBR)
• fully instrumented calorimeter ( is the final electronics there ?)
• 1 (TBR) ACD tile (at some point we will have a full ACD mechanical model)

For the moment (after talking to R. Johnson) there are 2 possible approaches for the tracker mainly driven by schedule

1. EM has no instrumented trays and is used for mechanical/environmental test only.
2. EM has 3 trays (not sure how many with thin or thick converter)

BEAM TEST

•  Hard to justify unless we have the appropriate beam already in 2002 (very unlikely). The EM itself does not teach us more than what we have learned from previous SLAC test beams.
• Could drive the DAQ development ? Not really. In principle one could study DAQ issues by using cosmic rays or software enabled triggers. 
• If we come up with a well defined roadmap for the electron rejection using the TOT, then we could justify some studies on the electron background rejection using the new tracker electronics (very weak rationale for a huge test beam enterprise)
• Calorimeter is fully instrumented, but to do a "CAL only" test beam, the SLAC beam may not be appropriate. Then one can consider an EM test at CERN/GSI/FNAL. In this case, since the calorimeter would be the driver, that has to fit their schedule too.
• ACD does not have enough instrumentation to justify a test beam request.
• Most of the DAQ functions can be tested without the beam: command/control, setup, housekeeping, error reporting/correction, ... The abilities of the system can also be exercised by generating triggers at high rates by turning down the thresholds and/or charge injection and/or pulse generators. All that has to happen long in advance of the beam test! (Steve Ritz)
• Use EM to characterize the future beam for calibration. 

COSMIC RAYS

• EM certainly should be tested under cosmic rays since it will help setting up test instrumentation system at SLAC and one could study some DAQ issues.
• We will gather a valuable amount on environmental data that could be used to understand our requirements on the internal alignment of the tracker.

SOFTWARE

• Tracy Usher seems to believe that by early June we should have a MC available with enough flexibility that one could try different tray configurations for the EM. OF course, we need to convince ourselves that it is worth the effort.

SCHEDULE

• Put EM in the beam test to tune the beam. If schedule permits then add 1 or 2 towers and then 4 towers ? (Hartmut)

EQUIPMENT

• Need to investigate Vavra's telescope for cosmic muons