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Muon Accelerator Program Winter Meeting, Jefferson Lab, 02/28-03/04/2011

Status of the Muon Collider Ring Design. Y. Alexahin (Fermilab APC). Baseline design (1.5TeV c.o.m.) Task list Recent progress - effect of IR dipole multipole errors (A.Netepenko) - fringe field of IR quads (V.Kapin) - collimation scheme - 3TeV c.o.m Lattice (Eliana)

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Muon Accelerator Program Winter Meeting, Jefferson Lab, 02/28-03/04/2011

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  1. Status of the Muon Collider Ring Design Y. Alexahin (Fermilab APC) • Baseline design (1.5TeV c.o.m.) • Task list • Recent progress - effect of IR dipole multipole errors (A.Netepenko) - fringe field of IR quads (V.Kapin) - collimation scheme - 3TeV c.o.m Lattice (Eliana) • Plans Muon Accelerator Program Winter Meeting, Jefferson Lab, 02/28-03/04/2011

  2. 2 1.5 TeV c.o.m. MC IR Layout y x Dx Rendition by A. Netepenko MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  3. 3 Coil aperture mm 160 Gap mm 55 Nominal field T 8 Nominal current kA 17.85 Quench field @ 4.5 K T 9.82 Rref=40mm b1=10000 b3=-5.875 b5=-18.320 b7=-17.105 IR Dipole IR dipole coil cross-section and good field region Calculated multipole components MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  4. 4 Task List - I • Lattice Design • fringe field & systematic multipole correction • *-tuning sections • collimation scheme • closed orbit & optics correction scheme • injection & abort • monochromatization scheme (?) • RF system • accelerating structure design • high-order mode analysis • impedance & wakefield calculations • longitudinal dynamics simulations MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  5. 5 Task List - II • Beam-Beam & Collective Effects • incoherent beam-beam simulations • transverse impedance & wakefield calculations • coherent beam-beam modes stability • plasma beam-beam compensation (?) • Designs for Different Energies/Species • IR for 3 TeV c.o.m. collider • Higgs / Top Factory (?) • -p collider (?) • Highlighted items must be done by the end of 2011, • others by the end of 2012 MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  6. 6 Effect on Chromatic Functions Wy Wy Dx Wx Wx Dipoles cut in short pieces with thin multipoles added Effect is strong but positive: Wy reduced by ~25%, easy to correct (just reduce strength of the 1st sext) MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  7. 7 Effect on Dynamic Aperture 1024 turns DA, no beam-beam, reference emittance 10 mm mrad Strong effect on DA is baffling, explained by change in detuning coefficient MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  8. 8 Sextupole Correction y Dx Quadratic effect dominates not allowing to reduce dQy/dEy x Corr. sext. MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  9. 9 Octupole Correction of Detuning Octupoles (placed at the same locations) allow to reduce dQy/dEy and restore DA. Effects of higher order multipoles in IR dipoles are yet to be studied 1024 turns DA, no beam-beam, reference emittance 10 mm mrad MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  10. 10 Fringe Field of IR quads (V.Kapin) y0 y0 x0 x0 1024 turns DA (MAD-X PTC) in units of initial coordinates atIP without (left) and with(right) quadrupole fringe field in hard-edge approximation. No beam-beam, Compare with the beam size of 6m at IP. MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  11. 11 Fringe Field of IR quads (cont’d) Ey Ey Ex Ex DA in the plane of Courant-Snyder invariants. Compare with r.m.s. emittance of 3.5 nm. Fringe-field effect is strong but not forbidding (we know that from K.Oide). MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  12. 12 * Tuning Section (Eliana) Dx y x Goal: vary * in a wide range w/o any change in Dx 6 conditions (on ,  and  in x, y) require 6 quads in a dispersion-free straight Is it possible to use this straight for halo removal? MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  13. 13 Halo Removal Idea (Mokhov et al., 1998) Electrostatic deflector is too weak for TeV energies, is ~100 kV ~5 ns pulsed deflector feasible? MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  14. 14 Induction Column (G.Caporaso et al.) Laser Optical fiber distribution system Proton source Focusing HGI SiC photoconductive switches Stack of Blumleins loaded on a central electrode (instead of a beam of particles) as a pulse source? Stack of “Blumleins” MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  15. 15 Plans • Lattice design: - complete 1.5TeV design with tuning & collimation sections - develop 3TeV design • Fringe fields & Multipoles: - include realistic long. profile (Enge function) in MAD-X (F.Schmidt, CERN) or borrow from COSY-Infinity (V.Kapin) - nonlinear corrector arrangement for fringe field and multipole error correction (V.Kapin, F.Schmidt) • Strong-Strong Beam-Beam Simulations: - K.Ohmi (KEK) is willing to join with MAP - A.Valishev and E.Stern (FNAL) also promised to look • Self-Consistent Longitudinal Dynamics: - V.Balbekov & L.Vorobiev (FNAL GS) can address it (using ORBIT?) MC Design Status- Y. Alexahin MAP meeting 03/02/2011

  16. Final Focus Quads 11 Requirements adopted for this design:  full aperture 2A = 10sigma_max + 2cm (Sasha Zlobin wants + 1cm more)  maximum tip field in quads = 10T (G=200T/m for 2A=10cm)  bending field 8T in large-aperture open-midplane magnets, 10T in the arcs  IR quad length < 2m (split in parts if necessary!) a (cm) 5y 5x z (m) Gradient (T/m) 250 187 -131 -131 -89 82 Quench @ 4.5K 282 209 146 146 (with inner radius 5mm larger) Quench @ 1.9K 308 228 160 160 Margin @ 4.5K 1.13 1.12 1.12 Margin @ 1.9K 1.23 1.22 1.22  Is the margin sufficient? If not lower beam energy or increase * to allow for smaller aperture  We don’t need 5sigma+ half-aperture, 3sigma+ is enough: can accommodate N=50 m!  No dipole field from 6 to 16.5m, is it worthwhile to create ~2T by displacing the quads? MC Lattie Design - Y.Alexahin FNAL, November 11, 2009 MC Lattie Design - Y.Alexahin 3rd MCDW BNL December 3, 2009

  17. One More Innovation: the Arc Cell 5 Dx (m) SY SA SY SX DDx/5 SX x y  Central quad and sextupole SA control the momentum compaction factor and its derivative (via Dx and DDx) w/o significant effect on chromaticity  Large  -functions ratios at SX and SY sextupole locations simplify chromaticity correction  Phase advance 300/ cell  spherical aberrations cancelled in groups of 6 cells  Large dipole packing factor  small circumference (C=2.6 km with 9.2T dipole field) Now C=2.5 km with B=10T MC Lattice Update - Y. Alexahin NFMCC Meeting Oxford, MS, January 14, 2010

  18. Momentum Acceptance 6 x* Qx Qy y* p p p c Fractional parts of the tunes With 2 IPs the central tunes are 18.56, 16.58 - good (!) for beam-beam effect - good for the orbit stability and DA  Static momentum acceptance = 1.2%, while the baseline scheme calls for only 0.3%  Central value of themomentum compaction factor = -1.4510-5, can be made even smaller MC Lattice Update - Y. Alexahin NFMCC Meeting Oxford, MS, January 14, 2010

  19. Muon Collider Parameters 9 h z /  “Hour-glass factor” s (TeV) 1.5 3 Av. Luminosity / IP (1034/cm2/s) 1.25* 5 Max. bending field (T) 10 14 Av. bending field in arcs (T) 8.3 12 Circumference (km) 2.5 4 No. of IPs 2 2 Repetition Rate (Hz) 15 12 Beam-beam parameter / IP 0.087 0.087 * (cm) 1 0.5 Bunch length (cm) 1 0.5 No. bunches / beam 1 1 No. muons/bunch (1012) 2 2 Norm. Trans. Emit. (m) 25 25 Energy spread (%) 0.1 0.1 Norm. long. Emit. (m) 0.07 0.07 Total RF voltage (MV) at 800MHz 20230 + in collision / 8GeV proton 0.008 0.007 8 GeV proton beam power (MW) 4.8 4.3 ----------------------------------------------------------------------- *) With increase by the beam-beam effect P – average muon beam power (~  ) – beam-beam parameter • C – collider circumference (~  if B=const) • – muon lifetime (~ ) • * – beta-function at IP MC Lattice Update - Y. Alexahin NFMCC Meeting Oxford, MS, January 14, 2010

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