To: Distribution 19 Feb 97
From: Martin Nordby
Subject: IR Engineering and Physics Meeting Minutes of 7 February 97
|Bob Bell||41||Nadine Kurita||18|
|Gordon Bowden||26||Jim Krebs||41|
|Pat Burchat||95||Harvey Lynch||41|
|Scott Debarger||17||Tom Mattison||17|
|Hobey DeStaebler||17||James Osborn||LBL B71J|
|Jonathan Dorfan||17||Andy Ringwall||17|
|Stan Ecklund||17||John Seeman||17|
|John Hodgson||12||Mike Sullivan||17|
|Hank Hsieh||LBL B71J||Uli Wienands||17|
|David Humphries||LBL 46-161||Mike Zisman||LBL B71J|
|Roy Kerth||LBL 50-340|
|Curt Belser||Kay Fox||Jeff Richman||Joe Stieber|
|Lou Bertolini||Fred Goozen||Natalie Roe||Jack Tanabe|
|Catherine Carr||Alex Grillo||Ross Schlueter||Rick Wilkins|
|Al Constable||J. Langton||Knut Skarpaas VIII||Fran Younger|
|David Coupal||Georges London|
|David Coward||Joseph Rasonn||Ben Smith|
Q2 Vacuum Chamber Update
Nadine Kurita and J. Langton reported on progress in laying out the final Q2 Chamber design. The LEB Chamber is squeezed between the BSC's and the pole inside of the Q2 Magnet. Since the BSC dimensions and positions change for running with our without solenoid compensation, and the orbit is different for incoming and outgoing LEB, there are 6 permutations of BSC positions for the chamber to fit around. Also, the Q2 Magnet is offset 5 mm vertically up on the incoming side, and 2 mm down on the outgoing. No "generic" LEB Chamber can fit around all of these permutations without hitting either the pole tip, the octupole trim windings, the main quad septum winding, or encroach on the BSC.
This is worsened by the proposal by James Osborn to displace the coil conductor by 4 mm toward the beam to improve Q2 harmonics. Currently, on the in-board end of the magnet, there is 3 mm of clearance between the chamber and the standard coil position., leaving only 2 mm of room for conductor displacement and 1 mm for alignment tolerance for the chamber.
J. is looking into making two different
shaped LEB Chambers. This is not preferred, since it increases
complexity and ED&I time. James will look at reducing the
size of the octupole trim, and possibly moving it to clear the
chamber (Stan will deliver a final spec. on octupole trim capacity,
for James to work with). He felt that the trims could be flattened,
and possibly reduced in cross-section, but their position is tied
to the higher harmonics they produce.
Q2 Magnet Update
James Osborn reported on progress in the Q2 Magnet analysis. He has found that displacing the inner conductor on the split-plane and deleting the inner condutor on the face of the pole root can essentially eliminate n = 6, 10, and 14 harmonics. Moving the other conductors did not seem to help. This suggests that it may be hard to reduce the 4 mm of displacement expected for the inner conductor. However, the entire coil package may be able to be displaced into the HEB passage somewhat to avoid encroaching on the LEB Chamber.
Mike Sullivan reported that the half-aperture
BSC's for the Q2 Magnet are thus (defined as 15 sigma + 2 mm):
At z = 3.5 m (the start of the Q4 LEB Chamber) the BSC is clipped by a 45 mm wide HER Arc Quad Chamber extrusion. This was needed to leave room for coil and support in the Q4 septum region. Since this is clipping the BSCx already, John Seeman and Mike Sullivan felt that extending this into the back end of the Q2 Magnet should not be an additional problem.
The following proposal and action plan was developed:
--Out-board end: reduce Q2 LEB Chamber half-width to 45 mm
--In-board end: reduce half-width by 1 mm (encroach BSCx by 1 mm)
--LEB Chamber: linearly taper chamber between in- and out-board ends
--Move Q2 coil conductor by 3.5 mm, max
--Add 0.5 mm alignment and fab tolerance to the Q2 LEB Chamber dim's.
--Flatten out skew octupole trims
and look into moving them
These minutes, and agenda for future meetings, are available on the Web at: