Beam-Based Alignment Procedure for ATF Quad and Skew Quad Shunt
This document outlines the Beam-Based Alignment (BBA) procedure for the ATF Quad and Skew Quad Shunt. The methodology involves making a closed local bump at the target BPM, utilizing quadrupole or sextupole trims for adjustments, and conducting a grid scan of bump amplitude and trim settings. By fitting the difference orbits relative to the trim settings, the beam position readings can be determined at the null of the magnetic field. The procedure concludes with a summary of results that illustrate the relationship between magnet strength changes and resulting fitted kicks across various beam positions.
Beam-Based Alignment Procedure for ATF Quad and Skew Quad Shunt
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Presentation Transcript
Beam Based Alignment at ATF Quad and Skew Quad Shunt BBA Procedure These slope of kick versus B field is then plotted versus beam position. The fit gives the beam position reading at the null of the magnetic field. • BBA Procedure • make a closed local bump at target BPM • use quadrupole or sextupole (skew quad) trims (ΔQ) • make grid scan of bump amplitude and trim setting • for each bump value make difference orbit w.r.t. to trim=0 • fit difference orbits for kick (k) at quadrupole or sextupole • for each bump value fit kick vs trim: k = f (ΔQ) = mΔQ+b • - m is offset from magnetic center • - for some trajectory through the magnet, m = 0 • plot fitted offset vs absolute reading of target BPM • - horizontal intercept is BPM offset Sample orbit to fit a kick at the Quad under test Summary of results For each beam position inside the magnet, the magnet stength is varied and the resulting fitted kicks are fit versus the beam position.
