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July 22, 2005CESRc miniMAC1 Introduction to CESRc Optics M. Billing
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July 22, 2005CESRc miniMAC2 Topology of CESRc Normal Arc S IR N IR HBs RF (Lattice Asymmetry)
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July 22, 2005CESRc miniMAC3 Quad/Sextupole Families There are no families! All quadrupoles –Independently powered in FODO configuration –Unipolar power supplies –Current resolution: 1.5x10 -5 of full scale All sextupoles –Independently powered –Bipolar power supplies –Current resolution: 2.4x10 -3 of full scale => Great flexibility in optics designs
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July 22, 2005CESRc miniMAC4 Primary Optics Constraints Optics Design uses a Figure of Merit –Based on weighted differences from Target Values (here called “Constraints”) General Parameters –Emittances x –Tunes, Q x, Q y Injection Parameters – x, y, x at Injection Point ( x & x determine the injection oscillation amplitudes in the rest of CESRc)
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July 22, 2005CESRc miniMAC5 Primary Optics Constraints IP Parameters – x *, y *, x * –Coupling matrix elements (Solenoid compensation: To keep y * small, want C 12 & C 22 small) –See following plots (Plot C-matrix in -normalized units: ) Lab Coords Eigen Coords
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July 22, 2005CESRc miniMAC6 CESRc IR Optics quad adjustable skew quad ) )
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July 22, 2005CESRc miniMAC7 Pretzel Constraints Basic Constraints –Phase advance linked with parasitic crossing separation, x Pr –Pretzel efficiency = min/max( x Pr / √ x ) over all parasitic crossings in the arcs e+ beam
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July 22, 2005CESRc miniMAC8 Horz Pretzel & Sextupoles Horizontal Pretzel –Differential displacement 2 x Pr between e+/e- Sextupole effects – x Pr in sextupole => quad ( ) for e+/e- => Pretzel dependant parameters –Tunes, Q x, Q y (tonality) –Twiss parameters, x, y, x, y, x (e.g. y * moves y * minimum in opposite directions!) –Initially-Linear Effects, but can become non-linear as ’s ’s are perturbed
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July 22, 2005CESRc miniMAC9 Pretzel Constraints Sextupole effects - minimize e+/e- differences (H separation in sextupole => differential quadrupole) so quadrupole & sextupole optics designed together –In arc x, y, x - e+/e- differences General Parameters –Emittances x –Tunes, Q x, Q y (are used to adjust the e+/e- tunes) –Chromaticities ( ), Q´ x, Q´ y –Chromatic Betas & Phases in arcs - d x /d , d y /d , d x /d , d y /d IP Parameters – x *, y *, x * –Differences of Coupling matrix elements
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July 22, 2005CESRc miniMAC10 Separation Constraints Additional Constraints for minimum Pretzel separation at Parasitic Crossings –B Parameter - Form: Each term represents the RMS vertical kick from its parasitic crossing Phenomenological / Experimental Justification from Lifetime Considerations –Long range tune shift at parasitic crossings Minimize the worst tune shift
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July 22, 2005CESRc miniMAC11 Wiggler Effects Linear –Focusing in the vertical plane only Q=0.1/wiggler (significant optics issue,but not really a problem) –Small skew quadrupole errors (locally compensated & not part of design) Non-Linear –Vert odd order multipoles –Other multipoles from field non-uniformity Model –3-D Design field model for the magnet –Model’s fields fit to an analytic functional expansion –Optics designs based on analytic expansion
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July 22, 2005CESRc miniMAC12 Group Controls Basic Idea –Software control of a large number of elements –Control for specific functions “Common” Knob Controls –QTUNEING (quads) [5] Q y [6] Q x –XQUNEING (sextupoles) /=== “Tonality” ===\ [1] Q y ´[2] Q x ´[3] ∂Q y /∂x Pr [4] ∂Q x /∂x Pr –PRETZING (H separators) [1] Pretzel Ampl[13] S IP separation
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July 22, 2005CESRc miniMAC13 More “Common” Knob Controls –VNOSEING (NIR quads: phase advance change within Vert separation bump in NIR) (launches vertical separation wave from NIR to SIR) [1] SIR V separation [2] SIR Diff V angle –BETASING (quads & skew quads) [1] y *[2] x * –SCMATING (quads & skew quads) [1] y * [2] c 12 *[3] c 21 * [4] c 22 *[5] c 11 * [6] y *
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