AP-CEBAF-Optics-2015-02-28
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Revision as of 07:33, 28 February 2015 by Satogata (Talk | contribs) (New page: This is a wiki page for references, information, and procedures about Feb 27-Mar 1 work to transversely match CEBAF Twiss parameters at the injector (~0L07), 1E03, and xE01 locations. == ...)
This is a wiki page for references, information, and procedures about Feb 27-Mar 1 work to transversely match CEBAF Twiss parameters at the injector (~0L07), 1E03, and xE01 locations.
Philosophy
The philosophy was developed at a 15:00 meeting in MCC, including Arne Freyberger, Mike Spata, Yves Roblin, Mike TIefenback, Todd Satogata, and Operations:
- use zigzag harp scans to identify quadrupole ranges for good optics/emittance measurements at each harp.
- modify qsUtility configuration files in the golden area and acquire optics/emittance measurements with traditional qsUtility scans.
- use qsUtility to analyze the scans and get measured horizontal/vertical Twiss parameters at the start of the respective scan quads.
- back-propagate measured Twiss parameters to the start of the upstream xS04 quadrupole.
- use the qsUtility betatron match module (which uses ced2elegant and elegant) to calculate the match, with match point at the harp, using xS04-xS10 quadrupoles for matching to distribute matching effort.
- evaluate and install the match.
- re-scan the harp and compare beam sizes to sqrt(emit_meas * beta_design)
Prerequisites at Each Measurement Location
- 4-8 uA tune beam to first dumplette downstream of match point.
- quad centering of BPM/quadrupole pairs for qsUtility scan quadrupoles.
- clean steering in region of measurement and downstream to maximize aperture, minimize beam losses.
- clean ORFP dispersion in region of measurement and correction. In particular, dispersion in both planes must be consistent with zero at scan quadrupoles and harp.
Procedure
- confirm harp is working and set harp parameters
- perform zigzag measurements to establish scan quadrupoles and ranges
- edit qsUtility configuration files
- perform qsUtility scans
- evaluate qsUtility data to get measured Twiss parameters and remittances
- back-propagate measured Twiss parameters to start of upstream xS04 quadrupole with elegant
- use qsUtility betatron match module to calculate xS04-xS10 match
- evaluate and install match
- re-scan harp and evaluate match effectiveness
- perform confirmation fopt