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LER steering MD: orbit issues

LER steering MD: orbit issues. W. Kozanecki, F. - J. Decker, J. Turner, G. Yocky. Methodology goal: reduce LER dispersion by steering LER flat (except PR02 straight, LER sext in PR02, LER colls, LTFB, & injection) algorithm ref. steer to target orbit = 0 exc. in PR02 straight (transitions!)

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LER steering MD: orbit issues

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  1. LER steering MD: orbit issues W. Kozanecki, F. - J. Decker, J. Turner, G. Yocky • Methodology • goal: reduce LER dispersion by steering LER flat (except PR02 straight,LER sext in PR02, LER colls, LTFB, & injection) • algorithm • ref. steer to target orbit = 0 exc. in PR02 straight (transitions!) • first steer w/ heavy emphasis to reducing corrector strength (eigenv. = 0.3) • then steer w/o XYCOR constraint • known bumps (LER SEXT, LER COLL, LER TFB) restored by feddback • first MICADO, then SVD, mostly in groups of 3 micros • Orbits: before, target, after • XYCORs, before & after • Steering problems

  2. Orbits, before & after Before MD Target orbit After steering, diff to target After steering, absolute

  3. X/YCORs before steering

  4. X/YCORs, before and after steering After steering Before MD Before MD After steering

  5. SVD idiosyncracies over 3 micros @ sharp boundaries inventive workarounds rqd Bugs D-group boundaries inconsistent handling of asymmetric BMAX limits Dual-database XYCORs Large sensitivity to tunes  slow! (esp. PR08: could only implement 2-3% at a time) sometimes jumped  nu_x < .5 tune feedback would help (AF) ST BPM problem Y*+,- inconsistent by 500-700 mu PR04-PR12: all BPMs on All XYCORs on exc. PR02 straight Steering difficulties

  6. Addtional info • Steering issues • see PEP e-log, swing shift, 10 Feb 04 swing shift • Impact of LER etay knobs on eta_y rms and eta*y (FJD) • summary: PEP e-log, 12 Feb 04, day shift, alst few postings • input data & other details: PEP e-log, 11 Feb 04 owl

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