FCC Accelerator Parameters Michael Benedikt Frank Zimmermann CERN
FCC Accelerator Parameters Michael Benedikt & Frank Zimmermann, CERN First FCC Physics Workshop, 16 -20 January 2017 on behalf of the FCC global design study team S. Aull, W. Bartmann, M. Benedikt, M. I. Besana, R. Bruce, O. Brüning, O. Brunner, X. Buffat, F. Burkart, H. Burkhardt, O. Butterworth, R. Calaga, S. Calatroni, F. Cerutti, S. Fartoukh, M. Fiascaris, C. Garion, B. Goddard, B. Haerer, W. Höfle, B. Holzer, J. Jowett, R. Kersevan, R. Martin, L. Mether, A. Milanese, S. Ogur, T. Pieloni, S. Redaelli, G. Rumolo, B. Salvant, M. Schaumann, D. Schulte, E. Shaposhnikova, L. Stoel, C. Tambasco, R. Tomas, D. Tommasini, J. Wenninger, F. Zimmermann, CERN, Switzerland; G. Guillermo, CINVESTAV Merida, Mexico; V. Kornilov, GSI Darmstadt, Germany; O. Boine-Frankenheim, U. Niedermayer, TU Darmstadt, Germany; T. Mitsuhashi, K. Ohmi, K. Oide, D. Zhou, KEK, Tsukuba, Japan; A. Chancé, B. Dalena, J. Payet, CEA, Saclay, France; P. Bambade, A. Faus-Golfe, J. Molson, LAL Orsay, France; A. Bogomyagkov, I. Koop, E. Levichev, P. Piminov, D. Shatilov, S. Sinyatkin, BINP, Russia; O. Etisken, Ankara U. , Turkey; M. Aiba, A. Saa Hernandez, PSI, Switzerland; J. -L. Biarrotte, A. Lachaize, IPNO, France; Y. Cai, J. Fox, Y. Nosochkov, A. Novokhatski, G. Stupakov, J. Seeman, M. Sullivan, SLAC, U. S. A. ; D. Teytelman, Dimtel, USA; J. Abelleira, E. Cruz, A. Seryi, JAI Oxford, U. K. ; R. Appleby, U. Manchester, U. K. ; M. Boscolo, F. Collamati, A. Drago. INFN-LNF, Italy; . Barranco, EPFL, Switzerland; S. Khan, B. Riemann, TU Dortmund, Germany, etc … Work supported by the European Commission under Capacities 7 th Framework Programme project Eu. CARD-2, grant agreement 312453, and the HORIZON 2020 project Euro. Cir. Col, grant agreement 654305, as well as by the German BMBF
Future Circular Collider Study GOAL: CDR and cost review for the next ESU (2019) International FCC collaboration (CERN as host lab) to study: • pp and AA collider (FCC-hh) main emphasis, defining infrastructure requirements ~16 T 100 Te. V pp in 100 km • 80 -100 km tunnel infrastructure in Geneva area, site specific • e+e- collider (FCC-ee), as potential first step • p/A-e (FCC-he) option, integration one IP, FCC-hh & ERL • HE-LHC with FCC-hh technology First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
proton colliders FCC-hh and HE-LHC
FCC-hh peak luminosity with constraints synchrotron radiation power / beam: total beam-beam tune shift limited maximum acceptable r: bending radius C: circumference nb: #bunches/beam Nb: #p/bunch E: beam energy rp: class. proton radius luminosity d n a r e w o p R S r o f la luminosity formu r e id ll o c n o r d a h d e it tune-shift lim with
FCC-hh peak luminosity with other constraint event pile up / Xing maximum acceptable σtot [mbarn] ≈ 42. 1 s -0. 467 -32. 19 s-0. 540 +35. 83 +0. 315 ln 2(s/34); s in units of Ge. V 2 ~112 mbarn at 14 Te. V, ~156 mbarn at 100 Te. V σinel [mbarn] ≈ σtot-11. 7 +1. 59 ln s - 0. 134 ln 2 s ~83 mbarn at 14 Te. V, ~110 mbarn at 100 Te. V luminosity r o f la u m r o f y it s o in lum r e id ll o c n o r d a h d e pile-up limit shorter bunch spacing could help? ! (e. g. 25→ 5 ns would increase nb 5 x!)
some constraints in numbers • synchrotron radiation power → associated cryogenics power (after various technological improvements and mitigation – higher beam-screen temperature etc. ) limits maximum number of protons (e. g. 1015 p/beam or beam current of ~0. 5 A for 100 km ring at 100 Te. V c. m. ) • maximum beam current + “turnaround time” (FCC + inj. ) constrain integrated luminosity • maximum peak pile up ~1000 or ~200 limits peak luminosity at 25 ns and 5 ns bunch spacing, respectively • maximum acceptable beam-beam tune shift 0. 01 or 0. 03 + optics (minimum b* ~0. 3 -1. 1 m) also limits peak luminosity
hadron collider parameters (pp) parameter FCC-hh HE-LHC* (HL) LHC collision energy cms [Te. V] 100 25 14 dipole field [T] 16 16 8. 3 circumference [km] 100 27 27 beam current [A] 0. 5 1. 27 (1. 12) 0. 58 bunch intensity [1011] 1 (0. 2) 2. 5 (2. 2) 1. 15 bunch spacing [ns] 25 (5) 25 1. 1 0. 3 0. 25 (0. 15) 0. 55 5 30 34 (5) 1 170 1020 (204) 1070 (214) (135) 27 IP b*x, y [m] luminosity/IP [1034 cm-2 s-1] peak #events/bunch crossing stored energy/beam [GJ] 8. 4 1. 4 (0. 7) 0. 36 synchrotron rad. [W/m/beam] 30 4. 1 (0. 35) 0. 18 transv. emit. damping time [h] 1. 1 4. 5 25. 8 2. 3 (15) 40 initial proton burn off time [h] First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017 17. 0 3. 4 *tentative
luminosity evolution over 24 h radiation damping: t~1 h PRST-AB 18, 101002 (2015) for both phases: beam current 0. 5 A, unchanged! total synchrotron radiation power ~5 MW. phase 1: b*=1. 1 m, xtot=0. 01, tta=5 h, 250 fb-1 / year phase 2: b*=0. 3 m, xtot=0. 03, tta=4 h, 1000 fb-1 / year First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
FCC-hh - 100 Te. V c. m. , 25 ns burn off slower than emittance damping → emittance control
FCC-hh - 100 Te. V c. m. , 25 ns in phase 2, b* 1. 1→ 0. 3 m, without (or with less) emittance control: tune shift increases during fill until reaching maximum of 0. 03
FCC-hh - 100 Te. V c. m. , 5 ns equilibrium emittance!
FCC-hh - 100 Te. V c. m. , 5 ns without emittance control (phase 2): tune shift increases during fill
HE-LHC - 25 Te. V c. m. , 25 ns b*=25 cm or 15 cm burn off faster than emittance shrinkage; tune shift decreases during fill
HE-LHC: pile up & performance 25 ns bunch spacing with 160 days of physics, 70% availability, 3 h turnaround time pile up of 1000 or shorter (e. g. b*=25 cm: 920 fb-1/year b*=15 cm: 1100 fb-1/year 5 ns) bunch spacing – what is easier? M. Benedikt, S. Fartoukh, F. Zimmermann
optimized cryo & vacuum system R. Kersevan, C. Garion, O. Boine-Frankenheim, V. Kornilov, F. Petrov, et al. FCC-hh: ≈5 MW SR power emitted in cold arcs beam screen at 40— 60 K (LHC at 5— 20 K) → better Carnot efficiency; but higher resistance → res. wall instability slits & wedge capture and hide photons → no photoelectrons in beam pipe proper possible further improvements (under study): • HTS coating to reduce the impedance a-C coating or laser treatment to reduce SEY
beam-screen temperature picked 50 K for efficiency and beam stability but for 4. 5 K magnets can also consider 110 K total cryo power Ph. Lebrun L. Tavian V. Baglin based on LHC screen 300 MW 200 MW 100 MW D. Schulte First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
FCC-hh layout NEW LAYOUT NOV. 2016 First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
FCC-hh full-ring optics regular arc cell interaction region ongoing: • beam dynamics studies • optimisation of each insertion • definition of system specifications (apertures, etc. ) • improvement of baseline optics and layout First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017 injection with RF betatron collimation extraction/ dumping momentum collim.
FCC-hh injector studies injector options: • SPS LHC FCC 100 km FCC intersecting version • SPS/SPSupgrade FCC • SPS -> FCC booster FCC SPS FCC current baseline is to fully re-use the existing CERN accelerator complex • injection energy 3. 3 Te. V from LHC First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
pp/p-pbar in the L-E plane First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
limits on integrated luminosity F. Z. et al, IPAC’ 16 integrated luminosity per year vs maximum pile-up, assuming 160 days of physics run, a machine availability A of 71%, two primary collision points (n. IP=2), nb=10600 bunches per beam, and a maximum beam intensity of Nb, 0=1015 protons; curves for different av. turnaround times tta First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
physics prospects distributed at FCC Week 2016 in Rome First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
could you help us respond? “There presently is no physics case for a 100 -Te. V hadron collider” R. Brinkmann, M. Wing, DESY, 2016 “A 100 Te. V p-p collider requires 50 x luminosity of HL-LHC [i. e. 3 x 1036 cm-2 s-1 or 140 ab-1]” B. Richter, SLAC, 2014 “A 100 Te. V p-p collider should be designed with lower luminosity [i. e. 1033 cm-2 s-1]” M. Harrison, BNL, 2015 First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
FCC-hh as A-A collider
FCC heavy-ion collider (Pb-Pb) • synchrotron radiation damping is about twice as fast • Pb nuclei are accompanied by intense fluxes of high energy quasi-real photons: • • powerful secondary beams extreme luminosity burn-off complicated collimator interaction stronger intra-beam scattering ultimately limits emittance J. Jowett, M. Schaumann PRST-AB 18, 091002 (2015) First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
FCC-hh as A-A collider beam energy [Te. V] c. m. energy/nucleon pair [Te. V] no. bunches / beam IP beta function [m] long. emit. rad. damping time [h] initial luminosity [1027 cm-2 s-1] peak luminosity [1027 cm-2 s-1] based on existing LHC complex; fast radiation damping; secondary beams from IP require dedicated collimators, … J. Jowett, M. Schaumann First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017 Pb-Pb 4100 39. 4 2072 Pb-p 50 62. 8 2072 1. 1 0. 24 24. 5 57. 8 1. 1 0. 5 2052 9918 M. Schaumann, “Potential performance for Pb-Pb, p-Pb, and p-p collisions in a future circular collider, Phys. Rev. ST Accel. Beams 18, 091002 (2015). A. Dainese et al. , “Heavy ions at the Future Circular Collider, ” contribution to forthcoming CERN Report on Physics at FCC-hh, http: //arxiv. org/abs/1605. 01389.
FCC-ee
FCC-ee scope A. Blondel, J. Ellis, C. Grojean, P. Janot, et al. JHEP 01 (2014) 164 q possible 1 st step of ~100 Te. V hadron collider (FCC-hh) First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
FCC-ee & CEPC exploit lessons & recipes from past & present e+e- and pp colliders FCC-ee LEP: high energy SR effects B-factories: KEKB & PEP-II: high beam currents top-up injection combining successful ingredients of recent colliders → extremely high luminosity at high energies Marica Biagini 2016 First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017 DAFNE: crab waist Super B-factories S-KEKB: low by* KEKB: e+ source HERA, LEP, RHIC: spin gymnastics
ee luminosity w crab waist and its constraints synchrotron radiation power / beam: beam-beam tune shift constant maximum acceptable Piwinski angle luminosity a l u m r o f y t i s o n i lum y r o t c , t fa W , Z , for H with
ee luminosity scaling FCC-ee vs LEP: x 4. 5 x 4 x 1. 5 -2 <x 2 x 1/251/50
FCC-ee luminosity per IP further increase with squeeze to by*=1 mm, bx*=0. 5 m monochromatization? a. QED Z baseline 2016, crab waist w 2 IPs by*=2 mm, bx*=1 m H? WW HZ CEPC First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017 ?
FCC-ee key parameters parameter FCC-ee energy/beam [Ge. V] 45 120 175 120 105 91500 770 78 50 4 30 6. 6 16. 6 3 5. 1 1. 3 2. 0 0. 0012 1. 67 7. 55 3. 1 3. 34 103 22 bunches/beam 30180 beam current [m. A] luminosity/IP x 1034 cm-2 s-1 energy loss/turn [Ge. V] 1450 207 90 0. 03 synchrotron power [MW] CEPC 100 LEP 2 RF voltage [GV] 0. 4 0. 2 3. 0 10 6. 9 3. 5 rms bunch length (SR, +BS) [mm] 1. 2, 6. 7 1. 6, 2. 0, 2. 4 3. 8 2. 1, 2. 5 2. 1, 2. 6 12, 12 rms emittance ex, y [nm, pm] longit. damping time [turns] crossing angle [mrad] beam lifetime [min] FCC-ee: 2 separate rings 0. 2, 1 0. 1, 1 0. 6, 1 1. 3, 2. 5 6, 18 22, 250 1320 72 23 39 31 30 30 30 0 0 67 57 61 434 94 185 CEPC: single beam pipe like LEP
low emittance “easy” for large rings emittance normalized to beam energy vs. circumference for storage rings in operation (blue dots) and under construction or being planned (red dots); the ongoing generational change is indicated by the transition from the blue line to the red line R. Bartolini
beamstrahlung – potential limit at 175 Ge. V synchrotron radiation in the field of opposing bunch at the IPs, ‘beamstrahlung’, can become lifetime limit for large bunch populations, small horizontal beam size & short bunches g e e h : ring energy acceptance lifetime expression by V. Telnov, modified version by A. Bogomyagkov et al r : mean bending radius at the IP (in the field of the opposing bunch) for acceptable lifetime, r h must be sufficiently large o flat beams (large sx) o bunch length o large momentum acceptance: aiming for ≥ 1. 5% at 175 Ge. V - LEP: <1% acceptance, Super. KEKB ~ 1. 5% V. Telnov, A. Bogomyagkov, E. Levichev, D. Shatilov, et al.
matched layouts: FCC-hh & FCC-ee 1, FCC-ee 2, FCC-hh layout 11. 9 m FCC-ee booster (FCC-hh footprint) IP 30 mrad FCC-hh/ ee Booster 9. 4 m 0. 6 m Lepton beams must cross over through the common RF to enter the IP from inside. Only a half of each ring is filled with bunches. Common RF (tt) Max. separation of 3(4) rings is about 12 m: wider tunnel or two tunnels are necessary around the IPs, for ± 1. 2 km. IP • 2 main IPs in A, G for both machines • asymmetric IR optic/geometry for ee to limit synchrotron radiation to detector ; ee injector bypass K. Oide
FCC-ee design snapshots off-momentum dynamic aperture at ttbar threshold (350 Ge. V) synchr. radiation in each element ± 2% OK for beamstrahlung IR layout & MDI SR masks, HOMs, luminosity monitor, …. First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017 impedance model / wake field
by* evolution over 40 years b* [m] year SPEAR PEP, BEPC, LEP PETRA TRISTAN DORIS CESR-c, PEP-II BEPC-II CESR DAFNE CEPC KEKB 6 mm 1. 2 mm Super. KEKB 0. 3 mm entering a new regime for ring colliders – Super. KEKB will pave the way towards b*≤ 2 mm FCC-ee 1 and 2 mm
Super. KEKB: extremely low b* Ie+=3. 6 A, Ie-=2. 6 A PSR ~ 13 MW C = 3 km beam commissioning started this year K. Oide et al. top up injection at high current by* =300 mm (FCC-ee: 1 mm) lifetime 5 min (FCC-ee: ≥ 20 min) ey/ex =0. 25% (similar to FCC-ee) off momentum acceptance (± 1. 5%, similar to FCC-ee) e+ production rate (2. 5 x 1012/s, FCC-ee: Super. KEKB goes beyond FCC ee/CEPC, testing all concept <1. 5 x 1012/s (Z cr. waist)
FCC-he
LHe. C: FCC-he template or precursor? LHe. C CDR (~600 pages) published in 2012
FCC-he based on LHe. C ERL separate arcs acceleration turn 1 acceleration turn 2 acceleration turn 3 10 GV SC linac deceleration turn 6 deceleration turn 5 10 GV SC linac deceleration turn 4 proton beam LHe. C collision point FCC-he collision point LHC/HE-LHC CLHe. C=CLHC/n CLHe. C=CFCC/m FCC n =3 or 4, m=11?
FCC-he key parameters
FCC-he ERL-ring luminosity of LR collider: (round beams) HD~1. 3 D. Schulte LHe. C 2010 Hfill~0. 8 highest proton average emaximize geometric overlap factor beam brightness current - head-on collision available - small e- emittance smallest possible limited by energy qc=0 proton b* function: recovery H ≥ 0. 8 - reduced l* hg efficiency - squeeze only one p beam Ie=15 m. A
FCC-he & HE-LHC-ep parameters parameter FCC-he ep at HE-LHC ep at HL-LHC LHe. C Ep [Te. V] 50 12. 5 7 7 Ee [Ge. V] 60 60 3. 5 1. 7 1. 3 bunch spacing [ns] 25 25 protons / bunch [1011] 1 2. 5 2. 2 1. 7 gep [mm] 2. 2 2. 5 2. 0 3. 75 electrons / bunch [109] 2. 3 1. 0 electron current [m. A] 15 15 15 6. 4 IP beta function bp* [m] 15 10 7 10 hourglass factor 0. 9 pinch factor 1. 3 proton-ring filling factor 0. 8 luminosity [1033 cm-2 s-1 ] 11 9 8 1. 3
FCC-he & HE-LHC-e. A parameters parameter FCC-Ae e. A at HE-LHC LHe. C EA [Te. V] 4100 1025 574 Ee [Ge. V] 60 60 60 2. 2 1. 1 0. 8 2215 592 ions / bunch [108] 1. 2 ge. A [mm] 0. 9 1. 0 1. 5 electrons / bunch [109] 11 11 4. 7 electron current [m. A] 15 15 6. 4 IP beta function b. A* [m] 15 10 10 hourglass factor 0. 9 pinch factor 1. 3 ion-ring filling factor 0. 8 e-N luminosity [1032 cm-2 s-1 ] 28 9 1. 5 no. bunches
summary
luminosity vs energy - most options
conclusions • FCC complex enables several high-energy high-luminosity colliders • performance constrained by operation cost, detector limits, and beam dynamics • sub designs optimized for cost & performance • does the projected performance meet physics needs? • it is of key importance to further develop and articulate the FCC physics programmes! First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
(incidentally, the only appearance of a Roman in the history of mathematics) “NOLI TURBARE CIRCULOS MEOS!“ Archimedes of Syracuse, 287 – 212 BC thank you for listening!
spare slides
hadron-collider beam power Collider c. m. Pel: tot. el. Pb: IP energy power beam [Te. V] [MW] power [GW] LHC 13. 0 ~150 8000 HE-LHC 25. 0 ~250 32000 (guess) FCC-hh 100. 0 50000 (target) SPPC 70. 2 600 70000 (guess) First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017 luminosity Pb/Pel L [nb-1 s-1] L/Pel (/IP) [nb-1 s-1 / MW] 10 340 50000 0. 07 128000 1. 4 300 (phase 2) 120 100000 0. 6 120000 0. 2
hadron collider history Hadron collider peak luminosity as a function of year – for past, operating, and proposed facilities [Courtesy W. Fischer]. First FCC Physics Workshop Frank Zimmermann CERN, 16 -20 January 2017
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