Difference between revisions of "AP-CEBAF-Optics-2015-02-28"

Revision as of 14:36, 1 March 2015

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, Jay Benesch, 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 if necessary
  • configuration files are in /a/opsdata/fiefdata/fileio/q/qsUtility/config/F3-0/GoldenTemplates
• perform qsUtility scans
• evaluate qsUtility data to get measured Twiss parameters and emittances
• back-propagate measured Twiss parameters to start of upstream xS04 quadrupole with elegant
  • A script to do this is in ~satogata/backpropagate.pl
• use qsUtility betatron match module to calculate xS04-xS10 match
  • configuration files are in /a/opsdata/fiefdata/fileio/q/qsUtility/match_config/F3-0
• evaluate and install match
• re-scan harp and evaluate match effectiveness
• After match is installed, one has to set the recombiner quads back to design in order to proceed to the next arc.
• perform confirmation fopt

Data and References

• Spring 2015 Optics Spreadsheet
• 0L injector match (E=107.2 MeV, BDL=536.365*K1 for L=0.15m magnets)
  • 0L07 H: zigzags -> MQD0L06 horizontal scan centered near 1800G, range +/-270G (BDL 3.35+/-0.5)
  • 0L08 V: zigzags -> MQB0L07 vertical scan centered near -3600G, range +/-500G (BDL -6.71+/-1.0)
• 1E03 match (E=1057.2 MeV, BDL=5289.659*K1 for L=0.15m magnets, be careful MQN1S04 is L=0.30m, others are L=0.15m):
  • 1E03 H: zigzags -> MQB1E02 horizontal scan centered near 3100G, range +/-700G (BDL 0.586+/-0.133)
  • 1E03 V: zigzags -> MQB1E01 vertical scan centered near -2900G, range +/-1200G (BDL -0.548+/-0.227)
  • Analysis and match calculation: e3322630
• 2E01 match (E=2007.2 MeV, BDL=20085.89*K1 for L=0.30m magnets):
  • 2E01 H: zigzags -> MQC2S10 horizontal scan centered near 4600G, range +/-1000G (BDL 0.229+/-0.05)
  • 2E01 V: No zigzag solution found. Todd explored space with qsUtilityConfig and found reasonable scan of MQC2S08 K=-0.6 to 0.6 with MQC2S09 K=-0.1 m^-2 and MQC2S10 K=0.2 m^-2 (image)
  • In order to test that with the zigzag do the following (yves):

# caput MQC2S09.BDL -2009
# caput MQC2S10.BDL 4017
# scan_script.csh run IHA2E01 MQC2S08 Y 12051 -12051 9
then restore the 2S09 and 2S10 quads .

• 3E01 match (E=2957.2 MeV, BDL=29592.47*K1 for L=0.30m magnets):
• 4E01 match (E=3907.2 MeV, BDL=39099.05*K1 for L=0.30m magnets):
• 5E01 match (E=4857.2 MeV, BDL=48605.63*K1 for L=0.30m magnets):
• 6E01 match (E=5807.2 MeV, BDL=58112.20*K1 for L=0.30m magnets):
• 8E01 match (E=7707.2 MeV, BDL=77125.36*K1 for L=0.30m magnets):
• 9E01 match (E=8657.2 MeV, BDL=86631.93*K1 for L=0.30m magnets):
• AE01 match (E=9607.2 MeV, BDL=96138.51*K1 for L=0.30m magnets):
• 5C00 match (E=10557.2 MeV, BDL=105645.09*K1 for L=0.30m magnets):
• 1C match (E=9607.2 MeV, fifth pass, BDL=96138.51*K1 for L=0.30m magnets):
• 2C match (E=2007.2 MeV, first pass, BDL=20085.89*K1 for L=0.30m magnets):
• rayTrace data: 3322485 H 3322488 H 3322490 V

Useful Tools

During the backpropagation or the matching calculation, if one wants to take into account quadrupoles that are off design, one can use the script ~roblin/tools/setquadstomachine which together with a snap file of the region in question produces a sdds file suitable for inclusion in the ELEGANT command file via load_parameters. usage is ~roblin/tools/setquadstomachine <commandfile> <snapfile> and it will make QUADparams.sdds ready for load_parameters. Read the comments in the script for further details (or page Yves).