27 July 1995
To: Distribution:
From: Stan Ecklund
Subject: "IR +- 2m Engineering"  Meeting Notes 21 July 1995

Steve Lund, from LLNL described his design of an elliptical 
aperture permanent magnet quadrupole, following and extending the 
formulation used for circular quadrupoles.  He is preparing a 
publication;  he will send Stan a draft copy.  Those at SLAC 
wishing a copy should so request from Stan.

Klaus Halbach presented calculations of demagnetization field in 
an iron free permanent quadrupole.  (See hardcopy version of notes 
for his transparencies)

Tom Mattison showed radial field for the DIRC end of the BaBar 
solenoid.  Peak radial fields are 0.12, 0.24, 0.42 and 0.8 Tesla 
at radii of 5, 10, 15, and 20 cm respectively.  This is a serious 
threat to demagnetizing blocks of Q1, resulting in bad harmonics.

Tom also presented results of a calculation of fields, projected 
on the magnetization direction, for a hybrid dipole-quadrupole Q1.  
These Q1 self fields are as big as 0.3 TESLA anti-parallel to the 
magnetization.  When combined with the solenoid radial field, 
there is a serious demagnetization problem with Q1 to be solved.  
Klaus related that different vendors of the same formula REC will 
supply materials with very different resistance's to 
demagnetization. 


Action Items:
1. Hybrid Q1 calculations: [Tom, Mike, Stan..]
     Radial fields from Solenoid;
     Demagnetizing Fields, Harmonics;
     Demagnetization properties of REC materials.
2. Look for ways to reduce cable interference. [Roy, Fred, Alex]
3. Drawing Updates: [Martin Nordby, Fred Goozen]
     Shielding, cables in Q1 section
4. HOM RF calculations with new mask geometry.  [Eddie Lin]
5. Check that a rotated BPM misses synchrotron rad fan. [Mike]
6. Shielding calculations [D. Coupal]
7. Required thickness of Q1 containment. [Martin]
8. Required thickness of Support Tube [Martin, J. Hodgson]
    calculate support tube deflection;
    earth quake deflection.
9. Mask & B1 3d cooling calculation. [J. Hodgson]
10  Beam generated noise to the drift chamber. [D. Coward]

No Meeting on 28 July
Next Meeting: 13:00 Friday  4 August 1995 in the Yellow room with 
TV to LBL

attachments: transparencies