16 June 1995
To: Distribution:
From: Stan Ecklund
Subject: "IR +- 1m Engineering"  Meeting Notes 16 June 1995

No new results on a hybrid dipole/quadrupole Q1.

Dave noted that the drift chamber id, which is driven by the 
support tube OD needs to be known by July 15 to avoid BABAR 
schedule slippage.

Dieter showed latest Be pipe design and table of radiation lengths 
for various configurations.  Eddie Lin is working on 3d 
calculation of HOM heating.  If power gets down below about 100 
watts we could reconsider He gas with water capability as a 
backup.  The manifolds would need redesign for high gas 
velocities.  The nominal design remains as water cooling.

Dave raised the issue of beam or wall current noise penetrating 
the vacuum chamber.  The drift chamber may be more sensitive than 
the vertex chamber because of the bandwidth of the signal 
processing.    

John reported on his 3d calculations on the B1 mask.  The source 
term on the mask is 17.9 W/mm (or 4KW total) corresponding to 3 
amperes in the LEB.  Max stress is 24 KPSI which is OK if not at a 
braze. With the present fabrication concept, brazes are wherever 
valleys occur in either plane.  Mike will check if synchrotron 
radiation normally can get to the valleys as was assumed in the 
calculation.  Next John will add the B1 magnet in 3d.

Alex reported that he is procuring twisted pair shielded cable to 
test, looking for a smaller package.  Kapton strip cables could be 
a possibility, but unfortunately  need more R&D time than is 
available.


Action Items:
1. Consider hybrid Q1 feasibility. [Martin, Stan, Mike,..]
2. Look for ways to reduce cable interference. [Roy,Alex]
     How much z space at Q1 inboard end is needed?
3. Drawing Updates: [Martin Nordby, Fred Goozen]
     Shielding, rotated BPM, Radial Ion pump,...
4. HOM RF calculations with new mask geometry.  [Eddie Lin]
5. Check that a rotated BPM misses synchrotron rad fan. [Mike]
6. Can we do with less shielding between B1 and Q1? [D. Coupal]
7. Required thickness of Q1 containment. [Martin]
8. Required thickness of Support Tube. [Martin]
9. Mask & B1 3d cooling calculation. [J. Hodgson]
10  Beam generated noise to the drift chamber. [D. Coward]
11.  Synch. radiation spatial dist. at B1 mask [M. Sullivan]
 
Next Meeting: 13:00 Friday  23 June 1995 in the Yellow room with 
TV to LBL

attachments: transparencies