Meeting of March 19, 2001

Present: Peter Bosted, Don Crabb, Keith Griffioen, Steve Rock, Piotr
         Decowski

1) Target. Don has been talking with John Weisend. He has started
   working on the detailed desing document. He asked Oxford and others
   for more quotes. His is investigating maxiumum transverse field.
   0.3 T should be relatively easy, but 0.5 T gets difficult. Concensus
   was to design for highest field that is relatively easy (ie doesn't
   cause a significant cost increase). Steve expressed concern that
   building in Research Yard are being torn down. Peter later talked
   to Steve St. Lorant, who waid building 113 should remain available.
   Perhpas Don could write a memo officially requesting use of such
   a building, so it gets put into SLAC planning.

2) Tracking. 
   Steve has done more work (see TN 2) on tracking. He finds
   if we have 9 planes, require 8 to fire, we can tolerate a sprinkle 
   hit rate of 2 to 3 hits/finger. Nine planes with about 1000 detectors
   is still enough to get adequate x and y resolution. 

   Peter looked at B.H. rates for E160. They are too high on mid-plane,
   so we need a several cm gap between top and bottom detectors. 
   The exact amount still needs to be dtermined. For E161, we want
   to detect BH events, so would reduce the gap down to zero.
 
   Piotr worked on Monte Carlo simulations. Using files generated by
   PYTHIA by Peter, each containing the products of 1200 nuclear
   interactions at energies of 15, 25, and 35 GeV (similar to a 
   typical E160 beam spill), Piotr found 100 to 300 charged particle
   hits/spill in front detector (increasing with energy), and 
   about 3 times less in the back detector. This is higher than the
   number of 80/spill in the proposal (which was a crude estimate).
   This rate may well be too high to reliably find J/psi pairs. 
   The rate is dominated by protons. More work is needed!
   Rates are lower in E161 since proposal says 3 m of alumina, versus
   2.2 m in E160. 
 
   Peter will revisit idea of measuring J/psi using e+/e- rather
   than mu+/mu-. This was the Cornell scheme. Subsequent thinking
   shows that e+/e- cannot work due to poor SLAC duty factor.

   Don said 225 channels of Lecroy HV are available for loan, 
   effective right now. Also, up to 78 of the 10 by 10 by 100 cm (??)
   scintillator bars from Jlab Gen will be avilable after this 
   summer. These could make a great back plane for the tracking.
   They have PMTs at each end, and very good timing. Are multi-hit
   TDC's needed for these?
  
Photon Beam. S. African group has agreed to join the collaboration.
   They need funding, though. They will try to get some. 
 
   Patrik Krejcik at SLAC is testing diamonds for radiation damage. 
   He will give information to Dieter on the company in Japan that
   made the diamonds. These diamonds are on loan from Argonne and
   are too small for us. 
 
   Keith talked to from Mainz who is an expert on diamond beams and
   is willing to help us with calculations. Peter will provide 
   information on beam divergences. 

Physics
   Keith gave a review talk at Seattle. Mark Strkman said he wished
   we could tag elastic J/psi with recoil protons. Keith will look
   into it, but it is almost certainly impossible due to high rates
   and low proton momentum.
 
Conferences
   Peter is invited to Spin 2001 in Beijing in October. Should he go
   or someone else? Don is going to a conference in Rome in July, but
   not giving a talk (plenary sessions only). Keith will gather
   information and put it on web page for everyone giving talks,
   and conferences we should find speakers for. Steve is going to
   Europhysics conf. in Budapest in July: hopes his talk will be accepted.