Bi-Weekly Gen Meeting

Wednesday, September 15, 2004; 10:30 - 11:30

attendees: T.Averett, G.Cates, T. Holmstrom, A.Kelleher, A.Kolarkar,
           R.Madey, B.Reitz, B.Wojtsekhowski

1) Planning of next collaboration meeting. It was suggested to 
   combine it with the next collaboration meeting of the polarized 
   Helium-3 group, therefore it was proposed to hold the two meetings
   December 13/14, 2004. BR will investigate, if this will conflict
   with the next Hall A collaboration meeting. 
   By this time the written document for the Gen readyness review 
   should be available to the collaboration, and the formal 
   review should take place some time in January 2005.

2) N-20 tests in Hall A

   Albert has installed the N20 test stand, with 20 UVA type 
   bars and veto detectors in Hall A. It is located at forward 
   angles on the right side, behind the DVCS detector, at large 
   distance from the target. All front end electronics and 
   the high-voltage is installed, and tested. BW reported, that 
   finally also the clean air supply for the PMTs was available.
   The DAQ for N-20 is not yet ready, BR is taking care of it.
   He has the VME crate, and the new F1-TDC in his office, to 
   set it up there, before moving it into the Hall. This can 
   be done later, during a downtime of DVCS.
   The plan is to first test out the system parasitically,
   however the main tests *) interfere with the running of DVCS.
   Ideally we would get dedicated beamtime (two days) after DVCS 
   is finished. Due to the already delayed start of DVCS ....

*) these tests aim at coincidences between the left HRS and 
   the N-20. The N-20 will be placed roughly at the angle 
   needed for the Gen experiment, but at larger distances.
   Momentum of the protons/neutrons also will be comparable.
   Electron arm will be placed at a smaller angle, to accommodate
   the higher beam energy, and to increase the coincidence rates.
   these tests require the DVCS detector to be moved, and 
   the trigger of the HRS to be adjusted.

3) Detector Design

   a) holders for neutron detectors and veto detectors are on order
   b) the BigBite detector frame was not ordered yet, the req. didnt 
      make it through the system. The req. will be signed in October
      and delivery is expected for January. BW will use this delay
      to modify the design - the tolarences on all dimensions were tighter 
      then actually necessary - hoping that this will reduce the costs.
   c) work on the design for the main cage of the neutron detectors  
      has been restarted
   d) the engineer, R.Hicks, is also looking into installation issues.
      B.W. and R.H. had a meeting with Ed Folts to discuss these items.
   e) all lead must be painted, costs are USD 7.- per brick, or 12.000.-
      in total
   f) for the BigBite trigger plane, USD 15.000.- are needed, N.Liyanga
      requested money from UVA, but so far has not been approved.
   g) First drift chamber for BigBite is working, work in the second
      progresses (wire stringing)
   h) Rutgers is modifying 10 preamp cards, to change signals from ECL
      to PECL, which is hoped to reduce the ringing, and therefore would 
      allow to run at lower discriminator thresholds.
      Solutions for repeater-cards (design available), or TDCs with 
      matching inputs were discussed.

4) Space

   For detector work the following spaces in the TestLab will get available:
   a) the area presently used for the SRC-BigBite detectors will
      be used for the Gen-BigBite detectors. SRC will move into 
      Hall A in December.
   b) the area next to it, previously used by PRIMEX, will get available 
      end of September or beginning of October, as soon as the 
      intermittently stored Hall B cherenkov detectors are moved.
   c) we will have those two areas until the Gen experiment starts.
      We want to fully assemble and test all detectors before 
      going into the Hall.

5) Misc.

   Plans for testing the drift chambers were discussed, ideally 
   the first DC is moved to Jlab in december, and could be 
   tested on beam during the second half of the SRC experiment.
   
   Earliest time for installation of Gen in the Hall is after 
   Thanksgiving 2005. In this scenario Gen might run in parallel
   to G0. Advantages and disadvantages of this and other combinations 
   were discussed.