1. Muon Accelerator Program Winter Meeting, Jefferson Lab, 02/28-03/04/2011 Status of the Muon Collider Ring Design  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 Y. Alexahin (Fermilab APC)

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

3. IR Dipole MC Design Status- Y. Alexahin MAP meeting 03/02/2011 3 Coil aperturemm160 Gapmm55 Nominal fieldT8 Nominal currentkA17.85 Quench field @ 4.5 KT9.82 Rref=40mm b1=10000 b3=-5.875 b5=-18.320 b7=-17.105 IR dipole coil cross-section and good field region Calculated multipole components

4. Task List - I MC Design Status- Y. Alexahin MAP meeting 03/02/2011 4 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

5. Task List - II MC Design Status- Y. Alexahin MAP meeting 03/02/2011 5 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

6. Effect on Chromatic Functions MC Design Status- Y. Alexahin MAP meeting 03/02/2011 6 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) Wy Wx Dx Wy

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

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

9. Octupole Correction of Detuning MC Design Status- Y. Alexahin MAP meeting 03/02/2011 9 1024 turns DA, no beam-beam, reference emittance 10  mm mrad 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

10. Fringe Field of IR quads (V.Kapin) MC Design Status- Y. Alexahin MAP meeting 03/02/2011 10 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. x0 y0 x0

11. Fringe Field of IR quads (cont’d) MC Design Status- Y. Alexahin MAP meeting 03/02/2011 11 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). Ex Ey Ex

12.  * Tuning Section (Eliana) MC Design Status- Y. Alexahin MAP meeting 03/02/2011 12  x  y 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? Dx

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

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

15. Plans MC Design Status- Y. Alexahin MAP meeting 03/02/2011 15  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?)

16. MC Lattie Design - Y.Alexahin FNAL, November 11, 2009 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!) 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? a (cm) z (m) 5y5y 5x5x MC Lattie Design - Y.Alexahin 3 rd MCDW BNL December 3, 2009

17. One More Innovation: the Arc Cell 5 SY DDx/5 Dx (m) SX SASY xx y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 Fractional parts of the tunes  Static momentum acceptance =  1.2%, while the baseline scheme calls for only  0.3%  Central value of the momentum compaction factor = -1.45  10 -5, can be made even smaller With 2 IPs the central tunes are 18.56, 16.58 - good (!) for beam-beam effect - good for the orbit stability and DA pp cc x*x* y*y* pp QxQx QyQy pp MC Lattice Update - Y. Alexahin NFMCC Meeting Oxford, MS, January 14, 2010

19. Muon Collider Parameters 9  s (TeV)1.53 Av. Luminosity / IP (10 34 /cm 2 /s) 1.25*5 Max. bending field (T)1014 Av. bending field in arcs (T)8.312 Circumference (km)2.54 No. of IPs22 Repetition Rate (Hz)1512 Beam-beam parameter / IP0.0870.087  * (cm)10.5 Bunch length (cm)10.5 No. bunches / beam11 No. muons/bunch (10 12 )22 Norm. Trans. Emit. (  m)2525 Energy spread (%)0.10.1 Norm. long. Emit. (m)0.070.07 Total RF voltage (MV) at 800MHz20 230  + in collision / 8GeV proton0.0080.007 8 GeV proton beam power (MW)4.84.3 ----------------------------------------------------------------------- *) With increase by the beam-beam effect P  – average muon beam power (~  ) C – collider circumference (~  if B=const)  – muon lifetime (~  )  * – beta-function at IP – beam-beam parameter h  z /   “Hour-glass factor” MC Lattice Update - Y. Alexahin NFMCC Meeting Oxford, MS, January 14, 2010