Subject: BBI compensation for off-energy particles
From: "James A. Crittenden"
Date: Wed, 14 Jun 2006 11:53:39 -0400
To: Mike Billing , Dave Rice , David Rubin , mjf7 , Stu Peck , John Sikora , jth@LNS61.LNS.CORNELL.EDU, Jerry Codner , Sasha Temnykh , Maury Tigner

In response to a request from ST, I looked specifically
at the dynamic apertures for off-energy particles, comparing
the global tune correction method to the local phase
advance and beta function correction method which
includes empirically tuned knob coefficients for compensating
the IP.

The calculations are for 8x3, 4 mA/bunch, PRZ1=2850 in the
4170_asol_2p5mA_20060213 lattice.

The plots can be seen at this link:
http://www.lns.cornell.edu/~critten/cesr/injection/notes/14jun06/all/

The first row shows the comparison for on-energy particles; the second
row shows the comparison for particles off-energy by 3.6 sigma.

The horizontal aperture improves from 3.0 sigma to 7.5 sigma using
the local BBI compensation for on-energy particles.
It improves from 2.0 to 3.5 sigma for the off-energy particles.

One can conclude that the improvement given by the local
BBI compensation method is not as effective for off-energy
particles as it is for on-energy particles.

-- jim

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James Crittenden                   Tel. (607) 255-9424
Wilson Synchrotron Laboratory      Fax  (607) 255-8062
Cornell University
Ithaca, New York 14853-8001
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