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This document outlines the PS2 orbit correction meeting held on November 16, 2007. It discusses error assignment related to misalignments and field errors of dipoles and quadrupoles, emphasizing the sensitivity of the orbit to these errors. The placement of monitors and correctors is detailed, with a focus on optimal positioning for effective correction. Results show significant improvements in orbit distortion post-correction, with detailed data on corrector kicks and monitor performances. Further studies and improvements needed for future corrections are also outlined.
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PS2 Orbit Correction Wolfgang Bartmann PS2 Meeting, 16-Nov 07
Outline • Error Assignment • Sensitivity of the orbit to different errors • Placement of monitors and correctors • Results for the orbit before/after correction • Summary • Further steps PS2 Orbit Correction
Error Assignment • MisalignmentsDipoles: 0.3 mm shift and 0.3 mrad angle for all axes Quadrupoles: 0.2 mm shift and 0.3 mrad angle for all axes • Field ErrorsDipoles ΔBL/Bρ : 0.510-3 All errors are gaussian distributed with a cut-off at 2σ PS2 Orbit Correction
Sensitivity to different errors Calculated with a sample of 50 machines; Qx,Qy = 14.21 (µ = 88.2°) PS2 Orbit Correction
Monitors and Correctors • Monitors measuring in both planes placed close to the quadrupoles (116 monitors) • Horizontal/Vertical Correctors placed at QFs/QDs (58 hor./58 vert.) • Phase advance between elements approx. 90° PS2 Orbit Correction
Placement of monitors and correctors µ=90 ° PS2 Orbit Correction
Results before/after correction • Calculated with a sample of 500 machines • Qx,Qy = 14.21 (µ = 88.2°) • Corrector kicks are below 1 mrad • All BPMs and Correctors are used PS2 Orbit Correction
Orbit before correction, hor.500 machines PS2 Orbit Correction
Orbit after correction, hor.500 machines PS2 Orbit Correction
Orbit before correction, vert.500 machines PS2 Orbit Correction
Orbit after correction, vert.500 machines PS2 Orbit Correction
Summary • Orbit distortion caused by magnet misalignments and field errors is comparable to other machines • Sensitivity of the orbit to different errors shows: • dipole field errors and transverse quadrupole shifts give the main error contributions for the horizontal plane • the transverse quadrupole shift and the tilt of the dipoles about the longitudinal axis dominate the error for the vertical plane • Correction of the uncorrected orbit with xmax up to 2 cm works well (factor 10 for uncorr/corr.) and gives a corrected xmax of below 2 mm; above 2 cm uncorr. orbit, the correction gives a factor of 3-4 PS2 Orbit Correction
Further steps to be studied: • Position of monitors and correctors in the dispersion suppressor and in the middle of the arc needs to be improved • Orbit correction for different tunes • Effect of the failure of monitors and correctors on the correction • Corrector strengths for different energies • Local orbit corrections at septa and sextupoles PS2 Orbit Correction