1 / 12

Optics for Skew Correction and Emittance Measurement

Optics for Skew Correction and Emittance Measurement. Leo Jenner This talk is going to look familiar if you were at the recent LC-ABD meeting in Manchester…. <x 2 > <xx’> <xy> <xy’> <xx’> <x ’2 > <x’y> <x’y’> <xy> <x’y> <y 2 > <yy’> <xy’> <x’y’> <yy’> <y ’2 >. = s.

mckile
Download Presentation

Optics for Skew Correction and Emittance Measurement

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Optics for Skew Correction and Emittance Measurement Leo Jenner This talk is going to look familiar if you were at the recent LC-ABD meeting in Manchester…

  2. <x2> <xx’> <xy> <xy’> <xx’> <x’2> <x’y> <x’y’> <xy> <x’y> <y2> <yy’> <xy’> <x’y’> <yy’> <y’2> = s 4D symmetric beam matrix To minimise the vertical emittance, especially for a flat beam, it is desirable to remove any cross-plane (x-y) correlations/couplings Coupling terms

  3. Sources of Skew Linac is main source of skew in ILC Skew correction section comes immediately afterwards and is the first sub-system of BDS

  4. Ideal Skew Correction + Emittance Measurement Layout 4 orthogonal skew quadrupoles correct xy, x’y’, x’y, xy’ 4 wire scanners / laser wires for emittance measurement

  5. 4D measurement simulation – 6 wire scanners required Measured Emittance Input Emittance Perturbed Projected Emittance Unperturbed Projected Emittance High Rejection Factor with realistic measurement errors

  6. 2D Measurement simulation with 4 wires scanners Calculated projected emittance Only 4 scanners – shorter, cheaper Scan in x and y separately Coupling is inferred from difference between measured and expected emittance – it seems this is good enough! Unperturbed projected emittance

  7. Correction procedure • Perturb beam with skew quads • Measure beam parameters with scanners • Infer coupling • Calculate skew correction • Apply to skew quadrupoles • (Iterate)

  8. Skew Quad Scanning Scan quad strength around nominal value to find minimum Fit parabola Extract parameters

  9. Coupling Correction in Action Projected/Actual emittance Skew Quad Scan Number

  10. Application1: ATF2

  11. Application 2: ILC BDS Skew Section

  12. Summary and Future Plans • Use ‘real’ ILC errors • Investigate alternative 4D methods • Investigate 2D/4D and/or BPM method • Incorporate simulation of Laserwire • Tweaking of ATF2/ILC optics

More Related