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A First Look at the TLEP Accelerator

A First Look at the TLEP Accelerator. Frank Zimmermann, CERN-BE o n behalf of the TLEP SG TH Seminar, 16 October 2013. thanks to R. Aleksan, R. Assmann , M. Benedikt, A . Blondel, Y . Cai, O . Dominguez, J . Ellis, B. Holzer, P . Janot, M . Koratzinos,

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A First Look at the TLEP Accelerator

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  1. A First Look at the TLEP Accelerator Frank Zimmermann, CERN-BE on behalf of the TLEP SG TH Seminar, 16 October 2013 • thanks to R. Aleksan, R. Assmann, M. Benedikt, A. Blondel, • Y. Cai, O. Dominguez, J. Ellis, B. Holzer, P. Janot, M. Koratzinos, • H. Maury Cuna, S. Myers, K. Ohmi, K. Oide, J. Osborne, • L. Rossi, J. Seeman, V. Telnov, R. Tomas, J. Wenninger, • S. White, U. Wienands, K. Yokoya, M. Zanetti, … Work supported by the European Commission under Capacities 7th Framework Programme, Grant Agreement 312453

  2. circular colliders & storage rings … CESR BEPC LEP Tevatron LEP2 HERA DAFNE PEP-II KEKB BEPC-II LHC SuperKEKB (soon) 3rd generation light sources • since 1960 ~30 ring colliders successfully built & operated 1992ESRF, France (EU) 6 GeV ALS, US 1.5-1.9 GeV 1993 TLS, Taiwan 1.5 GeV 1994ELETTRA, Italy 2.4 GeV PLS, Korea 2 GeV MAX II, Sweden 1.5 GeV 1996APS, US 7 GeV LNLS, Brazil 1.35 GeV 1997 Spring-8, Japan 8 GeV 1998BESSY II, Germany 1.9 GeV 2000ANKA, Germany 2.5 GeV SLS, Switzerland 2.4 GeV 2004SPEAR3, US 3 GeV CLS, Canada 2.9 GeV 2006: SOLEIL, France 2.8 GeV DIAMOND,UK 3 GeV ASP, Australia 3 GeV MAX III, Sweden 700 MeV Indus-II, India 2.5 GeV 2008SSRF, China3.4 GeV 2009PETRA-III, Germany 6 GeV 2011ALBA, Spain 3 GeV • + many more e±storage-ring light sources (with ever smaller transverse emittance) well understood technology & typically exceeding design performance within a few years

  3. LEP achievements integrated luminosity peak luminosity evenbetter at higher energy emittance ratio ex/ey R. Assmann Chamonix XI & APAC’01

  4. TLEP design targets • c.m. energies: 240 GeV (ZH) + 91(Z), 160(WW), 350(), [+ 500 GeV (ZHH,H)?] • luminosities: L: several 1034 cm-2s-1/IP at ZH, >> 1035cm-2s-1/IP at the Z • polarization up to WW for ~100 keV energy calibration • extendibility – reusing tunnel + infrastructure for 100-TeVppcollider, 1st step in HEP long-term vision P. Janot et al, arxiv1308.6176

  5. key constraints: in words … • SR power 100 MW ↔ wall plug power → beam current • limit on beam-beam tune shift: • extrapolated from LEP2 & KEKB & other colliders • #bunches ↔ luminosity, e-cloud, parasitic collisions • hor. emittanceex: bending radius r, optics (#magnets) • emittance ratio ey/ex: alignment, tuning, beam-beam • vertical b*y,: bunch length & optics • beam lifetime: • radiativeBhabha scattering (unavoidable) • beamstrahlung(design optimization)

  6. … and in formulae … and in formulae SR radiation power limit beam-beam limit constrained by beamstrahlung to be reduced as much as possible!

  7. lifetime limit: rad. Bhabha scattering beam lifetime at beam-beam limit: s for rad. Bhabha: help from theorists? → H. Burkhardt, R. Kleiss, EPAC1994 • LEP2: tbeam,LEP2~ 6 h (~30% suppression: s~0.21 barn) • TLEP with L~5x1034 cm−2s−1 at 4 IPs: • tbeam,TLEP~21 minutes, unavoidable

  8. lifetime limit: beamstrahlung (BS) • synchrotron radiation in the strong field of opposing beam • make some e± lose large part of their energy • h: momentum acceptance • sx: horizontal beam size at IP Note: Many theoretical beamstrahlung studies in 1980’s. Example R. Blankenbecler, S.D. Drell , “A Quantum Treatment of Beamstrahlung,” Phys.Rev. D36 (1987) 277 & then be lost→ limited beam lifetime with V. Telnov, PRL 110 (2013) 114801 • mitigations: • (1) large momentum acceptance h • (2) flat beams [i.e. small ey & large bx*] • (3) fast replenishing →minimize ke=ey/ex, by~bx(ey/ex) & respect by≥sz

  9. from LEP2 to TLEP-H • larger ring: higher energy or beam current • 4-5 x more SR power: 23 MW → 100 MW • a few times smaller emittanceat equal energy (r, cell length) • by* reduced by factor 50 - also requires smaller sz ~ by* (natural for larger ring) - steady-state BS energy spread ≤0.3% • top up injection to support short lifetime

  10. TLEP: double ring with topping up A. Blondel short beam lifetime (~tLEP2/40) due to high luminosity supported by top-up injection (used at KEKB, PEP-II, SLS,…); top-up also avoids ramping & thermal transients, + eases tuning

  11. top-up injection: schematic cycle beam current in collider (15 min. beam lifetime) 100% 99% almost constant current energy of accelerator ring 120 GeV injection into collider injection into accelerator 20 GeV acceleration time = 1.6 s (assuming SPS ramp rate) 10 s

  12. top-up injection at PEP-II top-up performance at PEP-II/BaBar Before Top-Up After Top-Up J. Seeman J. Seeman average luminosity ≈ peak luminosity similar results from KEKB

  13. TLEP Main Parameters energy = 91, 160, 240, 350 & 500 GeV c.m. circumference ~100 km total SR power ≤ 100 MW #IPs = 2 or 4 beam-beam tune shift / IP scaled from LEP luminosity / IP ~ 5x1034cm-2s-1 at the Higgs ~1000 x LEP2 top-up injection by* = 1 mm ~ sz

  14. com-parison with LEP2

  15. TLEP energy upgrade?

  16. similar proposals around the world SLAC/LBNL design: 27 km TLEP: 80 or 100 km near Geneva LEP3: 27 km TLEP (LEP4): 80 km near Geneva SuperTRISTAN in Tsukuba: 40 (& 60 or 80 “TLEP”) km or HF in 27-km LHC tunnel (“LEP3”) Y. Cai, U. Wienands, A. Chao et al Mike Koratzinos et al K. Oide FNAL site filler, 16 km FNAL Snowmass proposal: 100 km “TLEP” & FNAL VLLC 233 km ring Chinese Higgs Factory CEPC + Chinese pp Collider 50 or 70 km P. Bhat, T. Sen et al Qing QIN et al

  17. IR optics - momentum acceptance h with synchrotron motion & radiation (sawtooth) KEK design before optics correction KEK design after optics correction • IR optics w. up to h~2% acceptance ±1.1% ±1.3% K. Oide ±2.0% ±1.6% FNAL site filler SLAC/LBNL design Y. Cai T. Sen, E. Gianfelice-Wendt, Y. Alexahin

  18. Emittances in Circular Colliders & Modern Light Sources Y. Funakoshi, KEK no problem achieving target emittances with top up injection TLEP (240) R. Bartolini, DIAMOND

  19. b* history b* [m] year SPEAR PEP, BEPC, LEP PETRA TRISTAN DORIS CESR-c, PEP-II BEPC-II CESR DAFNE KEKB TLEP SuperKEKB IP beam size

  20. SuperKEKB – aTLEP demonstrator beam commissioning will start in early 2015 • by*=300 mm (TLEP: 1 mm) • lifetime 5 min (TLEP: ~15min) • ey/ex=0.25% ! (TLEP: 0.2%) • off momentum acceptance (±1.5%, TLEP: ±2%) • e+ production rate (2.5x1012/s, TLEP: <1x1011/s)

  21. luminosity of e+e- colliders TLEP-Z S. Henderson TLEP-W TLEP-H TLEP-t

  22. e+e- Higgs factories: luminosity ultimate precision at Z, WW, ZH ; sensitive to New Physics in multi-TeVrange & to SM closure → case for VHE-LHC ultimate energy reach up to 1 or 3 TeV ; direct searches for New Physics

  23. TLEP technical systems BNL 5-cell 700 MHz cavity • SC RF at ~800 MHz as developed for ESS, BNL, CERN SPL • need 12 GeV/turn at 350 GeV • ~600 m of SC RF cavities @ 20 MV/m • LEP2 had 600 m at 7 MV/m • high power : ~200 kW / cavity in collider • power couplers similar to ESS – 700-800 MHz preferred • cryogenics system for the RF • like LHC cryo system (~ ½ LHC’s) • arc magnets • ~500-700 G at top energy, ~50 G at injection • similar to LHeC prototype magnets RF Coupler (ESS/SPL) • we could build it tomorrow! LHeC dipole w 0.35 mm laminations (BINP) • LHeC dipole withone-turn conductor& air cooled • interleaved laminations [1 mm iron, 2 mm plastic] • (CERN)

  24. polarization LEP R. Assmann loss of polarization due to growing energy spread LEP observations + model predictions polarization scaling (energy spread!): LEP at 61 GeV → TLEP at 81 GeV TLEP optimized scenario TLEP U Wienands, April 2013  100 keVbeamenergy calibration byresonantdepolarization (using pilot bunches) aroundZpeak and W pair threshold: mZ~0.1 MeV, Z ~0.1 MeV, mW ~ 0.5 MeV r = 9000 m, C = 80 km lower energy spread, high polarization up to W threshold A. Blondel

  25. 80-100 km tunnel in Geneva region J. Osborne, C. Waaijer, CERN, ARUP & GADZ, submitted to European Strategy Symposium 2012 TLEP/VHE-LHC

  26. is 80-100 km too big? “Of course, it should not be the size of an accelerator, but its costs which must be minimized.” • Gustav-Adolf Voss, • builder of PETRA, • † 5. October 2013

  27. FCC study - scope & structure Future Circular Colliders (FCC) - Conceptual Design Study & Cost Review for next European Strategy Update Infrastructure tunnels, surface buildings, transport (access roads), civil engineering, cooling ventilation, electricity, cryogenics, communication & IT, fabrication and installation processes, maintenance, environmental impact and monitoring, safety Hadron collider Optics and beam dynamics Functional specifications Performance specs Critical technical systems Related R+D programs HE-LHC comparison Operation concept Detector concept Physics requirements e+ e- collider Optics and beam dynamics Functional specifications Performance specs Critical technical systems Related R+D programs Injector (Booster) Operation concept Detector concept Physics requirements Hadron injectors Beam optics and dynamics Functional specs Performance specs Critical technical systems Operation concept e- p option: Physics, Integration, additional requirements two pillars: pp & e+e-; emphasis on ppmachine, driving infrastructure

  28. possible long-term strategy TLEP (80-100 km, e+e-, up to ~350 GeV c.m.) PSB PS (0.6 km) LHC (26.7 km) SPS (6.9 km) HL-LHC VHE-LHC (pp, up to 100 TeVc.m.) & e± (120 GeV) – p (7, 16 & 50 TeV) collisions ([(V)HE-]TLHeC) ≥50 years of e+e-, pp, ep/A physics at highest energies

  29. tentative long-term time line 1980 2000 2010 1990 2030 2020 2040 Design, R&D LHC Constr. Physics Proto. Design, R&D Constr. Physics HL-LHC Design, R&D TLEP Physics Constr. Design, R&D Constr. Physics VHE-LHC

  30. back up

  31. synchroton-radiation: heat load TLEP has >10 times less SR heat load per meter than PEP-II or SPEAR! (though higher photon energy) N. Kurita, U. Wienands, SLAC SR heat per meter lower than for many operating rings

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