Status of FCC-hh Machine Studies in Europe Daniel Schulte for the FCC team FNAL, August 2014

2 FCC-hh Daniel Schulte FNAL August Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 Kick-off, collaboration forming,  study plan and organisation Release CDR & Workshop on next steps Workshop & Review  contents of CDR Workshop & Review  identification of baseline Ph 2: Conceptual study of baseline “strong interact.” Workshop & Review, cost model, LHC results  study re-scoping? Ph 3: Study consolidation Report Prepare 4 large FCC Workshops distributed over participating regions Ph 1: Explore options “weak interaction” Reminder: Proposed FCC Timeline We are just now starting the work and the collaboration needed to get organised wait for the P5 To a large extend identified problems to be addressed a work programme and partners that will take on responsibilities Did start to do some technical work

3 FCC-hh Daniel Schulte FNAL August 2014 Put together something that is reasonable Somewhat conservative With some aggressive choices to avoid excessive cost To criticise and improve To guide the design work and identify challenges Seed of the baseline More aggressive choices will be considered as alternatives When more R&D is required When they involve a performance/cost trade-off Authors: A. Ball, M. Benedikt, L. Bottura, O. Dominguez, F. Gianotti, B. Goddard, P. Lebrun, M. Mangano, D. Schulte, E. Shaposhnikova, R. Tomas, F. Zimmermann Rational for Parameter Choice

4 FCC-hh Daniel Schulte FNAL August 2014 Two main experiments sharing the beam-beam tuneshift Two reserve experimental areas not contributing to tuneshift Currently assume 25ns as baseline May be able to reduce bunch spacing and background Might be able to increase bunch length Will explore this if experiments find it useful 80% of circumference filled with bunches Physics Parameters Cms energy Luminosity LHCHL-LHCHE-LHCFCC-hh Cms energy [TeV] Luminosity [10 34 cm -2 s -1 ]1555 Bunch distance [ns]2525 (5) Background events/bx (34) Bunch length [cm]7.5 8

5 FCC-hh Daniel Schulte FNAL August 2014 Need to determine overall layout LHC-type with 12 insertions (1.4km average, pairwise same length) Racetrack-type with two almost straight sections (each 8.4km) Fill factors include dispersion suppressors (80.5% in the cell) Ambitious magnet strength goal 16T (Ni 3 Sn) or 20T (with high temperature superconductor) Basic Machine Parameters LHCHL-LHCHE-LHCFCC-hh Dipole field [T] (20) Magn. Aperture [mm]5640 Arc fill factor [%]79 Straight section8x0.5km16.8km Total length26.7km100(83)km

6 FCC-hh Daniel Schulte FNAL August 2014 Need to decide on layout LHC-type layout Racetrack (like SSC) Or something else Need to find site close to CERN Civil engineering study started Geology, surface site availability, … Need to integrate ring with LHC, if used as injector FCC Layout and Site

7 FCC-hh Daniel Schulte FNAL August 2014 Long cell => good dipole filling factor (fewer and shorter quadrupoles) Short cells => more stable beam (smaller beta-function) Scale from LHC Natural scaling for same technology 107m => ~300m For FCC magnet technology => 200m Dipole length should be similar (transport) First lattice design exists (B. Holzer, R. Alemany Fernandez) Arc Cell Layout LHC arc cell 106.9m

8 FCC-hh Daniel Schulte FNAL August 2014 Arc Dipoles Arc dipoles are the main cost and parameter driver Baseline is Nb 3 Sn at 16T HTS at 20T also to be studied as alternative Field level is a challenge but many additional questions: Field quality, aperture needs, … Different design choices (e.g. slanted solenoids) should be explored Goal is to develop prototypes in all regions Coil sketch of a 15 T magnet with grading, E. Todesco

9 FCC-hh Daniel Schulte FNAL August 2014 Values in brackets for 5ns spacing Same values for 16T and 20T design Beam-beam tuneshift for two IP 0.01 Beta-function at IP scaled with sqrt(E) from one LHC insertion line design with 0.4m (some safety margin)  Beam current  Bunch charge  Emittance as function of bunch charge Beam Parameters LHCHL-LHCHE-LHCFCC-hh Bunch charge [10 11 ] (0.2) Norm. emitt. [  m] (0.44) IP beta-function [m] IP beam size [  m] (3) RMS bunch length [cm]7.55 8

10 FCC-hh Daniel Schulte FNAL August 2014 At 100 TeV even protons radiate significantly Total power of 5 MW (LHC 7kW)  Needs to be cooled away Equivalent to 30W/m /beam in the arcs LHC <0.2W/m, total heat load 1W/m Critical energy 4.3keV, close to B-factory Protons loose energy  They are damped  Emittance improves with time Typical transverse damping time 1 hour Synchrotron Radiation

11 FCC-hh Daniel Schulte FNAL August 2014 Most of the power will be cooled at the beam screen, i.e. at its temperature A part is going into the magnets, i.e. cooled at 2-4K Current ambitious goal beam aperture: 2x13mm magnet aperture: 2x20mm Space for shielding: 7mm LHC-Type Beam Pipe Design

12 FCC-hh Daniel Schulte FNAL August 2014 Better use only some temperatures in order to maintain good vacuum 190K 100MW 200MW 300MW Power for Cooling Multi-bunch instability growth time: 25 turns 9 turns  Q=0.5) Choose 50K for now Need 20x5MW=100MW for cooling Photon stops? Open midplane?

13 FCC-hh Daniel Schulte FNAL August 2014 Copper Coating N. Mounet  Q=0.5, can probably assume this upper limit on working point Need maybe 300  m of copper coating  Difficult because of eddy currents in quench  Induces stress on beam pipe  LHC has 50  m HTS coating? Lots of work Impedance, coating technology, ecloud, …

14 FCC-hh Daniel Schulte FNAL August 2014 R. Tomas Interaction Region and Final Focus Design Two design being investigated: L * = 46m / 38m (how much is needed?)    = 0.8m / 0.3m (goal <1.1m) It is easier to obtain small beta- functions with shorter L* Will have a tendency to reduce L* Need to understand detector requirements as soon as possible Many issues need to be addressed Magnet performance Radiation effects Space constraints from experiments Beam-beam effects and mitigation …

15 FCC-hh Daniel Schulte FNAL August 2014 Lattice design, working point, dynamic aperture, … Beam-beam effects, crossing angle and potential compensation Collision point Parasitic encounters Beam current limitations E.g. arc impedance, collimator impedance, electron cloud, Feedback, octupoles, … Impact and mitigation of magnet imperfections Emittance measurement/control in collision (longitudinal/transverse) Collimation, losses, radiation, machine protection, … … Some Example Performance Issues

16 FCC-hh Daniel Schulte FNAL August 2014 >8GJ kinetic energy per beam Airbus A380 at 720km/h 24 times larger than in LHC at 14TeV Can melt 12t of copper Or drill a 300m long hole  Machine protection Also small loss is important E.g. beam-gas scattering, non-linear dynamics Can quench arc magnets Background for the experiments Activation of the machine  Collimation system Machine Protection and Friends

17 FCC-hh Daniel Schulte FNAL August 2014 D. SchulteCERN summer student lectures, LHC-type solution but other solutions should be investigated hollow beam as collimator crystals to guide particles renewable collimators Collimation

18 FCC-hh Daniel Schulte FNAL August 2014 Total power of background events 100kW per experiment (a car engine) Already a problem in LHC and HL-LHC (heating, lifetime)  Improved shielding required Shield (TAS) Magnets But need to open aperture Machine Protection and Friends II F. Cerutti et al.

19 FCC-hh Daniel Schulte FNAL August 2014 Beam lifetime due to burn-off considered Assume to keep transverse emittance proportional to charge Assume longitudinal emittance is kept constant Average luminosity is about 50% of maximum Operation FCC-hh Luminosity lifetime [h] 19.1 Turn-around time [h]5 Optimum run time [h]12.1 Int. lumi / day [fb -1 ]2.2 

20 FCC-hh Daniel Schulte FNAL August 2014 Consider using an injector in the tunnel of SPS LHC FCC collider ring Injection Important challenge to fill the FCC circumference with bunches Injected batches will be lost Need gaps between batches  Fast kickers (with acceptable impedance)  Robust design Need to match geometry of Injector and FCC-hh collider ring Power consumption, turn-around time, … High brilliance beams and short bunch spacings need exploration

21 FCC-hh Daniel Schulte FNAL August 2014 Luminosity depends on the number of circulating particles And on how much luminosity one obtains per particle Use a round beam  x  y Need to push beta-function, beam-beam tuneshift, injector brightness, turn-around time to either reduce beam current or increase luminosity Flat beams also to be considered General Luminosity Considerations Beam brightness (beam- beam tuneshift, IBS) Collision point beta-function Beam current

22 FCC-hh Daniel Schulte FNAL August 2014 Very First Ion Considerations UnitLHC Design FCC- hh Operation mode-Pb-Pb p-Pb Number of bunches Part. P. bunch[10 8 ] (1.4)/1.4 β-function at the IP[m] RMS beam size at IP[um] Initial luminosity[10 27 cm -2 s -1 ] (3.2) Peak luminosity[10 27 cm -2 s -1 ] (3356) Integr. lumi. per fill [  b -1 ] < Total cross-section[b] Initial luminosity lifetime[h]< (10.6) Much more work to be done: Improved injectors, integration into interaction region, … M. Schaumann

23 FCC-hh Daniel Schulte FNAL August 2014 Collaboration is being established Based on MoUs, where possible First management meeting September 9-10 at CERN Technical workshop March 2015 Please join EU Design Study proposal to be submitted September 2, covers Arc design, Interaction region insertion, Cryogenic beam vacuum system conception, High field accelerator magnet design ALBA, CNRS, CIEMAT, CEA, EPFL, INFN, KIT, STFC, TUD, TUT, UOX, ULIV, UT, CERN Have FCC-hh Design Meetings at 16:00 CET on Thursdays You are welcome to sign up (send to Collaboration

24 FCC-hh Daniel Schulte FNAL August 2014 Single beam collective effects Beam-beam collective effects and dynamic aperture Collimation and absorber concepts Injection and extraction concepts and designs Ion beam operation design considerations Interaction region and final focus design Lattice design and integration and single particle dynamics Machine detector interface Machine protection, magnet protection, QPS, BLM concepts Radiation maps and effects HE-LHC performance needs and conceptual design RF and feedback conceptual design FCC-hh Functional Design Workpackages Many technologies also need work Magnets (arc and insertions) Collimators Vacuum system …

25 FCC-hh Daniel Schulte FNAL August 2014 Work/meeting structures established based on INDICO, see: -FCC Study: In particular: -FCC-hh Hadron Collider Physics and Experiments VIDYO meetings - -Contacts: -FCC-ee Lepton Collider (TLEP) Physics and Experiments VIDYO meetings - -Contacts: Work and Organisation

26 FCC-hh Daniel Schulte FNAL August FCC-hh Hadron Collider VIDYO meetings - -Contacts: -FCC-hadron injector meetings - -Contacts: -FCC-ee (TLEP) Lepton Collider VIDYO meetings - -Contacts: -FCC infrastructure meetings - -Contacts: Work and Organisation II

27 FCC-hh Daniel Schulte FNAL August 2014 Have a first baseline parameter list Technological challenges need to be addressed to prove its feasibility Need to optimise the parameters and design and develop alternatives for improved performance/cost A large amount of work lies ahead Many important and interesting studies and developments are required US in a great position to contribute Collaboration is forming Excellent time to join Conclusion Thanks to the FCC team

28 FCC-hh Daniel Schulte FNAL August 2014 Reserve

29 FCC-hh Daniel Schulte FNAL August 2014 Average Luminosity

30 FCC-hh Daniel Schulte FNAL August MHz seems a good baseline 16MV minimum with no margin 32MV seems fine 200MHz appear somewhat low Needs higher voltage (>100MV) Or longer bunches (12cm) 800MHz appears too high Combination of 200 and 400MHz? RF Design Considerations Assumed impedance (x2) E. Shaposhnikova Bunch length 32MV 24MV 16MV Feedback design is critical Emittance control also

31 FCC-hh Daniel Schulte FNAL August 2014 Arc design Magnet performance dependent One of the main parameter drivers Layout of insertion lines Experiment insertions Collimation Injection and extraction Others (RF, additional experiments) Geometry Racetrack vs. LHC-type layout In the first stage, need to determine required lengths for beam lines and identify and address the main issues Overall Layout

32 FCC-hh Daniel Schulte FNAL August 2014 Using the same components and transverse dimensions This allows to stay with the same quadrupole gradient and dipole strength Change of technology modifies this, e.g. for FODO cell Lattice Scaling

33 FCC-hh Daniel Schulte FNAL August 2014 Goal: L * >= 25m, need to iterate with the experiment   = 1.1m Total length < 1400m Rogelio’s approach Based on LHC IR design Scaled according to energy and length Interaction Region and Final Focus Design

34 FCC-hh Daniel Schulte FNAL August 2014 R. Tomas Interaction Region and Final Focus Design

35 FCC-hh Daniel Schulte FNAL August 2014 L * = 46m Achieves    = 0.8m About 1100m long Need to verify separation Some iterations useful Improvements possible Excellent start Baseline appears possible R. Tomas Note: small beta-function can reduce synchrotron radiation Interaction Region and Final Focus Design

36 FCC-hh Daniel Schulte FNAL August 2014 Loss of Landau damping Filling factor in momentum Need enough voltage to keep beam stable Filling factor should not exceed 0.8 E. Shaposhnikova 400MHz Option

37 FCC-hh Daniel Schulte FNAL August 2014 Need to quantitatively asses physics parameters Flux of photons increases with B, 1.3x10 17 m -1 s -1, i.e. twice LHC Critical energy 4.3keV, i.e. 100 times LHC, similar to KEKB, photoemission yield? Photon capture efficiency? Likely need mitigation techniques Need hardware studies, simulation studies and beam experiments Electron Cloud W/m O. Domingues Sanches De La Blanca

38 FCC-hh Daniel Schulte FNAL August 2014 Have chosen total tuneshift of 0.01 Should be conservative value Damping will decrease emittance and increase tuneshift Need to explore how we can control the luminosity and emittance Noise into feedback, kickers, small beam-beam offsets, … Need to measure emittance in collision Can we live with larger tuneshift like in a lepton ring? Can we just wait for an equilibrium? Can the luminosity be controlled, i.e. not too high? The beams will probably tend to become flat. What are the consequences? Which experiments do we need? Operation and Head-on Beam-beam Effects

39 FCC-hh Daniel Schulte FNAL August 2014 Likely will have more parasitic crossings than in LHC Longer L* Potentially shorter bunch spacing (down to 5ns) Study impact and mitigation techniques Choice of beam parameters Crab cavity Wires Electron lenses Impedances Collimators … Feedback Tolerances and single particle effects Much to be learned from the LHC Collective Effects and Mitigation

40 FCC-hh Daniel Schulte FNAL August 2014 Values in brackets for 20T magnet field Radiation given by beam energy and dipole field Leads to damping of the longitudinal and transverse emittance Leads to significant power load on the beam screen Synchrotron Radiation LHCHL-LHCHE-LHCFCC-hh Dipole field [T] (20) Synchr. Rad. in arcs [W/m/aperture] (44) Eng. Loss p. turn [MeV] (5.9) Crit. eng. [keV] (5.5) Total synr. Power [MW] (5.8) Long. Damp. Time [h] (0.32) Transv. Damp. Time [h] (0.64)

41 FCC-hh Daniel Schulte FNAL August 2014 Cost Main direct cost driver are the arcs Main part of the circumference Dipoles are the single most expensive component Luminosity performance Experimental insertion design Beam-beam effects Current limitations … Robustness Clean conditions for the experiments and stable machine Collimation, machine protection … Cost optimisation will put stress on performance and robustness Parameter Drivers

42 FCC-hh Daniel Schulte FNAL August 2014 Dipoles are critical for FCC-hh design and cost Achievable dipole field Cost as a function of aperture (and field) Strong cost increase with increasing aperture Practical minimum aperture is likely 40mm (L. Bottura) Use this as an ambitious target Tolerances and field quality important for the beam and cost In particular field quality at injection energy Dynamic aperture, alignment, … Currently consider four beam pipe design approaches LHC-type copper coated beam screen (baseline) LHC-type beam screen coated with high temperature superconductor Use of photon stops Open midplane magnets Arcs

43 FCC-hh Daniel Schulte FNAL August 2014 Need to understand how to operate in the 40-60K temperature window, if heat load changes Transparency of beam screen is important for vacuum quality and impedance Shielding of magnets from synchrotron radiation load Try to use less space than in LHC but with higher load This appears very challenging High temperature superconductor (HTS) coating? Electron cloud (photon absorption, secondary emission yield of HTS, …) Potentially photon stops, … Beam Pipe, Vacuum, Cryogenics

44 FCC-hh Daniel Schulte FNAL August 2014 Copper Coating N. Mounet  Q=0.9  Q=0.5  Q=0.1