14 April 1995
To: Distribution:
From: Stan Ecklund
Subject: "IR +- 1m Engineering"  Meeting Notes 14 April 1995

Mike showed a re-optimized 3-tip LEB mask which accommodates the 
required mask cooling input tube.  This gives new inner radii 
values for B1 resulting in a B1 strength equal to the CDR value 
(no margin).  Increasing the outer radii by 2,3,4,4,5,5,5 mm 
respectively for blocks 2 through 8 results in a B1 strength 3.6% 
higher than CDR (or 3.6% margin).  This leaves 4 mm for cooling 
the outer side of the blocks and another 1 mm for clearance to the 
300 mr line.  Stan showed the results of moving the outer radii of 
blocks 2 through 8 out another 4 mm (using the cooling space) and 
decreasing all inner block radii by 1 mm (reducing air gap to 2 
mm).  It gives 10% margin over the CDR.  

Stan discussed some of the advice obtained from talking to magnet 
experts.  Generally it is expected that one can get within 3% of 
expected remnant field, within a degree of the correct direction.  
Space between blocks could result in another 3% loss in strength.  
Recommended margin ranged from a few % to 15%. A margin of 10% 
would seem adequate or comfortable?  

John Hodgson reported on results of cooling the out board ends of 
the PM blocks assuming a constant crossection 9 mm thick brass 
"pressure vessel" holding the blocks.  He finds cooling only the 
back end results in good temperature uniformity for B1.  This 
result, somewhat surprising, depends on the air gap insulation 
between B1 and the mask.

Fred and Roy showed the cooling cone geometry and the gimbals 
arrangement.

We discussed the treaty line and clearance zone (DMZ) between 
vertex cone and B1 outer surface.  Working proposal is the cone 
stays outside of 300 mr + 1 mm.  B1 stays inside 300 mr - 2 mm.  
Treaty line is slightly more complicated at the front end of B1;  
a drawing and r,z table will be generated by Roy/Fred early next 
week.  Written treaty surface to be agreed on then.

Action Items:
1. Refine B1 temperature stabilization calculation.  [John H.]
2. SVT drawing update showing "treaty line".  [Roy K, Fred G.]
3  Update drawing: [Martin Nordby, Fred Goozen]
     Show location of SVT gimbals.  [Roy K]
     Get radiation detector dimensions.  [Roy K]
     Latest mask, B1 block dimensions.
4. Number and location of holes in support barrel. [Gordon]
5. HOM RF calculations with new mask geometry.  [Eddie Lin]

attachments: Transparencies

Next Meeting: 13:00 Friday  21 April 1995 in the Yellow room with 
TV to LBL