Specification Of Harmonic Corrections Wirefix For The Slc Arcs

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Download or read book Specification of Harmonic Corrections (wirefix) for the SLC ARCS. written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the original SLC commissioning plans, it was thought that accumulated optical mismatch, generated by focusing errors in the whole machine, would be corrected at the very end, in the Final Focus. Dedicated correctors for optical matching and a special adjustment strategy were planned for this purpose, with a large tuning range of up to about a factor four in any dimension of the beam phase-space. With the present collimation and shielding arrangements, it is necessary to control the beam upstream of the Final Focus in order to inject a nearly matched phase-space there. We have developed and installed a new system of harmonic focusing corrections at the end of the SLC Arcs, to provide such control. The scheme consists of introducing small regular and skew focusing deviations at specific harmonics of the betatron frequency which the phase-space is specially sensitive to. The harmonics in question are the zeroeth harmonic and the second harmonic of the betatron frequency. The focusing deviations are introduced in the Arc lattice by perturbing the strengths of the combined function magnets with a set of appropriately rewired trim windings at their backleg. The corrections provide an efficient way for adjusting both for errors in the Arc lattice and for mismatch at the injection to the Arc, generated by the upstream systems. In this note, we describe the specification of this correction procedure as well as the present installation. Initial operational experience with this new method for adjusting beam-lines is presented elsewhere. 20 refs., 18 figs.