7 April 1995
To: Distribution:
From: Stan Ecklund
Subject: "IR +- 1m Engineering"  Meeting Notes 7 April 1995

Stan showed the results of B1 field calculations for various 
configurations.  The goal is to obtain the CDR parasitic crossing 
distance and integral BL with some margin for engineering the 
magnet details.  That margin is not known (by us) yet; Stan will 
consult with experts who have built magnets.  Suggestions are: 
Egon Hoyer, Klaus Halbach, Jim Spencer, Gordon Bowden, Dieter 
Walz.

Running the LER with a high emittance increases sigma at the 
parasitic crossing, decreasing d/sigma from 11.8 to 8.4 for the 
CDR value of d=3.5 mm.  John Seeman decided this is still OK.

Roy showed several reconfigurations of the vertex chamber and the 
B1 magnet with modifications to accommodate a stronger B1.  Two 
show magnet configurations from June 93 (CDR) and Aug. 94.  The 
others show the latest magnet block configuration.(#3 in Summary)  
Vertex chamber modifications involve shortening layers 1 and 2 by 
a small amount and reshaping the cone at the inboard end.
Variations are:
   1. moving out cone 5 mm.
   2. same as 1 but tilting the cone to give 10 mm at the outboard 
      end. 
These changes will allow increasing outer radii of B1 permanent 
magnet blocks.  The first block is full z size of 25 mm.  The 
chamber support gimbals which needs to be close to the IP will 
probably be outside the first block.  Next step is to check that 
B1 can be made strong enough with one of these variations and 
refine both Vertex detector and machine components.

Mike showed results of changes in LEB mask to accommodate cooling 
near far end of B1.  Going to a fourth tip on the mask can solve 
the problem and also allows moving B1 blocks to smaller radii.  
This geometry is #9 in Summary.  Per Martin Nordby, a minimum 12 
mm thickness is needed for Cu and cooling channel.  Three mm is 
reserved for B1 inner collar, thermal insulation, and alignment 
space.  He will next look at re-optimizing a three tip mask.

Action Items:
1. Investigate B1 temperature stabilization.  [John H.]
2. Refine SVD geometry  [Roy K]
3  Show location of SVD gimbals on drawing  [Roy K]
4. Get radiation detector dimensions for drawing.  [Roy K]
5. Calculate fields with increased outer radii per new SVD [Stan]
6. Consult experts and assign margin for B1 field. [Stan]
5. Re-optimize three tip mask [Mike]
6. Update and drawing. [Martin]
7. Number and location of holes in support barrel. [Gordon]
8. HOM RF calculations with new mask geometry [S. Heifets]

attachments: Transparencies

Next Meeting: 13:00 Friday  14 April 1995 in the Yellow room with 
TV to LBL