CERN Accelerating science

Article
Title	Decoupling Schemes for the Tevatron in the Presence of Skew Quadrupole Fields
Author(s)	Johnstone, Carol ; Berz, Martin ; Snopok, Pavel
Affiliation	(Fermilab, Batavia, Illinois) ; (MSU, East Lansing, Michigan)
Publication	2005
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.1850
Subject category	Accelerators and Storage Rings
Abstract	With increasing demands for luminosity, optimal performance must be extracted from the existing Tevatron optics. We have, therefore, initiated a high-order dynamical study of the Tevatron to assess the performance, functionality and potential of the baseline lattice. This work describes the nonlinear or high-order performance of the Tevatron lattice with emphasis on the coupled and increased nonlinear behavior introduced by the significant skew quadrupole error in combination with conventional sextupole correction, a behavior still clearly evident after optimal tuning of available skew quadrupole circuits. An optimization study is then performed using different skew quadrupole families, and, importantly, local and global correction of the linear skew terms in maps generated by the code, COSY. A correction scheme, with two families locally correcting each arc and eight independent correctors outside the arc for global correction is shown to be optimal and dramatically improve the linear performance of the baseline Tevatron lattice.