TLEP–Accelerator Design Study

Frank Zimmermann4th TLEP workshop, CERN, 4 April 2013

work supported by the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no. 227579

cern.ch/accnet

Thanks to R. Aleksan, R. Assmann, P. Azzi, M. Bai, A. Blondel, O. Brüning, H. Burkhardt, A. Butterworth, Y. Cai, A. Chao, W. Chou, P. Collier, J.-P. Delahaye, J. Ellis, M. Fitterer, P. Janot, E. Jensen, M. Jimenez, M. Klein, M. Klute, M. Koratzinos, E. Meschi, A. Milanese, M. Modena, S. Myers, K. Ohmi, K. Oide, J. Osborne, H. Piekarz, L. Rivkin, L. Rossi, G. Roy, D. Schulte, J. Seeman, V. Shiltsev, M. Silari, D. Summers, V. Telnov, R. Tomas, J. Wenninger, U. Wienands, K. Yokoya, M. Zanetti, …

Photo: TLEP seminar at LAL, 22.03.2013

Source: Francois Le Diberder, Clermont Ferrand, March 2013

all lost (or almost lost) HEP

PSB PS (0.6 km)SPS (6.9 km)

LHC (26.7 km)

TLEP (80-100 km, e+e-, up to ~350 GeV c.m.)

VHE-LHC (pp, up to 100 TeV c.m.)

LEP3(e+e-, 240 GeV c.m.)

circular Higgs factories at CERN & beyond

& e± (120 GeV) – p (7, 16 & 50 TeV) collisions ([(V)HE-]TLHeC)

≥50 years of e+e-, pp, ep/A physics at highest energies

a long-term strategy for HEP!

HE-LHC (33 TeV)

“same” detectors!

option 1: installation in the LHC tunnel “LEP3” + inexpensive (<0.1xLC)+ tunnel exists+ reusing ATLAS and CMS detectors+ reusing LHC cryoplants- interference with LHC and HL-LHC

option 2: in new 80-km tunnel “TLEP”+ higher energy reach, 5-10x higher luminosity+ decoupled from LHC/HL-LHC operation & construction+ tunnel can later serve for VHE-LHC (factor 3 in energy from tunnel alone)- more expensive (?)

circular e+e- Higgs factories LEP3 & TLEP

key parametersLEP3, TLEP

LEP3 TLEPcircumference 26.7 km 80 kmmax beam energy 120 GeV 175 GeVmax no. of IPs 4 4 luminosity at 350 GeV c.m. - 0.7x1034 cm-2s-1 luminosity at 240 GeV c.m. 1034 cm-2s-1 5x1034 cm-2s-1 luminosity at 160 GeV c.m. 5x1034 cm-2s-1 2.5x1035 cm-2s-1 luminosity at 90 GeV c.m. 2x1035 cm-2s-1 1036 cm-2s-1

at the Z pole repeating LEP physics programme in a few minutes…!

«Pre-Feasibility Study for an 80-km tunnel at CERN»John Osborne and Caroline Waaijer, CERN, ARUP & GADZ, submitted to ESPG

80-km tunnel in Geneva area – “best” option

even better100 km?

80-km Tunnel Cost Estimate (preliminary!)

• Costs– Only the minimum civil requirements (tunnel, shafts and

caverns) are included – 5.5% for external expert assistance (underground works only)

• Excluded from costing– Other services like cooling/ventilation/ electricity etc– service caverns– beam dumps– radiological protection– Surface structures– Access roads– In-house engineering etc etc

• Cost uncertainty = 50% • Next stage should include costing based on technical

drawings21 February 2013

John Osborne & Caroline Waaijer (CERN)

CE works Costs [BCHF]

Underground

Main tunnel (5.6m)

Bypass tunnel & inclined tunnel access

Dewatering tunnel

Small caverns

Detector caverns

Shafts (9m)

Shafts (18m)

Consultancy (5.5%)

TOTAL ~3.1? (unofficial)

(→raw tunnel cost could be 4.5 BCHF)

luminosity formulae & constraints

𝐿=𝑓 𝑟𝑒𝑣𝑛𝑏𝑁 𝑏

2

4𝜋 𝜎𝑥𝜎 𝑦

=( 𝑓 𝑟𝑒𝑣𝑛𝑏𝑁 𝑏)(𝑁 𝑏

𝜀𝑥) 1

4𝜋1

√𝛽𝑥 𝛽𝑦

1

√𝜀𝑦 /𝜀𝑥

𝑁𝑏

𝜀𝑥=𝜉 𝑥2𝜋𝛾 (1+𝜅𝜎 )

𝑟 𝑒

( 𝑓 𝑟𝑒𝑣𝑛𝑏𝑁 𝑏)=𝑃𝑆𝑅𝜌

8.8575×10−5 mGeV−3 𝐸

4

𝑁 𝑏

𝜎 𝑥𝜎𝑧

30𝛾𝑟𝑒2

𝛿𝑎𝑐𝑐𝛼<1

SR radiation power limit

beam-beam limit

>30 min beamstrahlung lifetime (Telnov) → Nb,bx

→minimize ke=ey/ex, by~bx(ey/ex) and respect by≈sz

LEP2 LHeC LEP3 TLEP-Z TLEP-H TLEP-tbeam energy Eb [GeV] circumference [km] beam current [mA] #bunches/beam #e−/beam [1012] horizontal emittance [nm] vertical emittance [nm] bending radius [km] partition number Jε momentum comp. αc [10−5] SR power/beam [MW] β∗

x [m] β∗

y [cm] σ∗

x [μm] σ∗

y [μm] hourglass Fhg

ΔESRloss/turn [GeV]

104.526.7442.3480.253.11.118.5111.552703.50.983.41

6026.710028085652.52.61.58.1440.181030160.990.44

12026.77.244.0250.102.61.58.1500.20.1710.320.596.99

45.58011802625200030.80.159.01.09.0500.20.1780.390.710.04

1208024.38040.59.40.059.01.01.0500.20.1430.220.752.1

175805.4129.020 0.19.01.01.0500.20.1630.320.659.3

LEP3/TLEP parameters -1 soon at SuperKEKB:bx*=0.03 m, bY*=0.03 cm

SuperKEKB:ey/ex=0.25% even with 1/5 SR power (10 MW) still > LILC!

LEP2 LHeC LEP3 TLEP-Z TLEP-H TLEP-tVRF,tot [GV] dmax,RF [%]ξx/IP ξy/IPfs [kHz] Eacc [MV/m] eff. RF length [m] fRF [MHz] δSR

rms [%] σSR

z,rms [cm] L/IP[1032cm−2s−1] number of IPs Rad.Bhabha b.lifetime [min] ϒBS [10−4] nγ/collision DdBS/collision [MeV] DdBS

rms/collision [MeV]

3.640.770.0250.065 1.67.54853520.221.611.2543600.20.080.10.3

0.50.66N/AN/A0.6511.9427210.120.69N/A1N/A0.050.160.020.07

12.05.70.090.082.19206007000.230.319421890.603144

2.04.00.120.121.29201007000.060.19103352 3740.413.66.2

6.09.40.100.100.44203007000.150.174902 16150.504265

12.04.90.050.050.43206007000.220.25652 27150.516195

LEP3/TLEP parameters -2 LEP2 was not beam-beam limited

LEP data for 94.5 - 101 GeV consistently suggest a beam-beam limit of ~0.115 (R.Assmann, K. C.)

beam-beam effect (single collision)

TLEP: negligible beamstrahlung apart for effect on beam lifetime

TLEP-H TLEP-t ILC (250) ILC (350)beam energy [GeV] 120 175 125 175disruption Dy 2.2 1.5 23.4 84.5

ϒBS [10−4] 15 15 207 310

nγ/collision 0.50 0.51 1.17 1.24

DdBS/collision [MeV] 42 61 1265 2670DdBS

rms/collision [MeV] 65 95 1338 2760

LEP2: • beam lifetime ~ 6 h • due to radiative Bhahba scattering (s~0.215 b)

TLEP:• with L~5x1034 cm−2s−1 at each of four IPs:

tbeam,TLEP~16 minutes from rad. Bhabha • additional lifetime limit due to beamstrahlung

(1) large momentum acceptance (dmax,RF≥3%), (2) flatter beams [smaller ey & larger bx

*, maintaining the same L & DQbb

constant], or (3) fast replenishing(Valery Telnov, Kaoru Yokoya, Marco Zanetti)

beam lifetime

SuperKEKB: t~6 minutes!

circular HFs – top-up injectiondouble ring with top-up injection

supports short lifetime & high luminosity

top-up experience: PEP-II, KEKB, light sources

A. Blondel

beamstrahlung lifetime• simulation w 360M macroparticles • t varies exponentially w energy acceptance h• post-collision E tail → lifetime t

beam lifetime versus acceptance dmax for 4 IPs:

M. Zanetti

SuperKEKB: ey/ex <0.25%!

ey/ex =0.4%ey/ex =0.1%

FNAL site filler

±1.6%

circular HFs - momentum acceptance

±2.0%

SLAC/LBNL design

K. Oide

KEK designafter optics correction

±1.3%

with synchrotron motion &radiation(sawtooth)

KEK designbefore optics correction

±1.1%

T. Sen, E. Gianfelice-Wendt, Y. AlexahinY. Cai

circular HFs: synchroton-radiation heat load

LEP3 and TLEP have 3-10 times less SR heat load per meter than PEP-II or SPEAR! (though higher photon energy)

N. Kurita, U. Wienands, SLAC

A. Fasso3rd TLEP3 Day

synchrotron radiation - activation

see talk by A. Ferrari

originalLEP design

LHeC/LEP3 polarization

LHeC equilibrium polarisation vs ring energy, full 3-D spin tracking results (D. Barber, U. Wienands, in LHeC CDR, J. Phys. G: Nucl. Part. Phys. 39 075001)

“… by adopting the levels of alignment that are now standard for synchrotron-radiation sources and by applying harmonic closed-orbit spin matching, there is reason to hope that high polarisation in a flat ring can … be obtained”

80% at the Z pole

LEP3 (27 km)

TLEP (80 km)x1.3

80 (GeV)

transverse polarizationabove WWthreshold!?

loss of polarization due to growing energy spread

see talk by U. Wienands

TLEP key components

tunnel SRF system cryoplants magnets injector ring detectors

tunnel is main costRF is main system

RF system parameters – 175 GeVLHeC TLEP collider TLEP inj.

beam energy [GeV] 60 175 175frequency [MHz] 720 or 800total voltage [GV] 20 12 12av gradient [MV/m] 20 20 20eff. RF length [km] 1 0.6 0.6#cavities 1000 600 600RF efficiency (wall→beam) 55% 55% 55%power throughput [MW] 17 110 10 (peak)power / cavity [kW] 17 183 17

total TLEP RF ~ LHeC RF! high-power TLEP RF: more power throughput

high power

RF system parameters – 120 GeV*LHeC TLEP collider TLEP inj.

beam energy [GeV] 60 120 120frequency [MHz] 720 or 800total voltage [GV] 20 6 4av gradient [MV/m] 20 10 7eff. RF length [km] 1 0.6 0.6#cavities 1000 600 600RF efficiency (wall→beam) 55% 55% 55%power throughput [MW] 17 23 1 (peak)power / cavity [kW] 17 38 <2

*low power version with 20 MW total SR power

low power

low power TLEP RF: much relaxed

wall-plug to beam power efficiency?Francois Le Diberder, March 2013, at a seminar in Clermont Ferrand, has pointed out several ”errors” in the TLEP proposal.E.g. he suggested that TLEP RF efficiency cannot be better than 17% of ILC, while theTLEP proposal assumes 50%!? Similar obviously wrong statements (vis-a-vis LEP, CEBAF, CLIC DB, ...)have been made before by ILC colleagues

in truth TLEP wall-plug to beam power efficiency can be ≥3x more than for ILC

Le Diberder & colleagues are ignoring key differences of TLEP & ILC (LC) RF, such as cw vs. pulsed, gradient, klystron mode of operation,…

see talk by E. Jensen

power – LEP2 experienceG. Geschonke, LINAC96

LEP2 SC system4 mA /beam,3.6 GV total RF,→ 25.9 MW wall plug power, incl. cryogenics!

11 MW SR power/beam

→ efficiency ~42%(2.5x ILC)

power consumption for TLEP at 175 GeV (MW)TLEP

Wall-plug RF power 218 (1) [181 w/o RF feedback]

RF cryo power 24 (2)

Magnet system power 6 (3)

Cooling and ventilation 60 (4)

Experiments 25 (5)

General services 15 (5)

SPS & PS as pre-injectors (20 & 3.5 GeV) 5 (6)

e-/e+ source & pre-pre-injector 1(7)

Total 354 [318 w/o RF feedback]

(1): wall power efficiency: power converters: 95%; klystron efficiency: 65%; transmission losses 7%; overall 55% (from the LHeC design report); includes 36 MW for RF feedback margin (which may not be necessary)(2): 60% of LHeC ; cryo power depends on cavity Q0 (34 kW at 2 K for 1200 cavities with Q0 =2.5e10)(3): from LHeC ring-ring magnet design; power for 1 magnet (5.4 m, 0.075 T) = 270 W; assuming 2x80 km of magnets at 0.065 T (dipole field for 175 GeV beam energy)(4): TLEP three times more than LHC; maximum capacity for LEP(5): as for LHC (see appendix)(6): conservative estimate scaled from higher-energy proton operation(7): L. Rinolfi, private communication Mike Koratzinos & F.Z.

power consumption for TLEP* at 120 GeV (MW)TLEP

Wall-plug RF power 44 (1)

RF cryo power 6 (2)

Magnet system power 6 (3)

Cooling and ventilation 30 (4)

Experiments 25 (5)

General services 15 (5)

SPS & PS as pre-injectors (20 & 3.5 GeV) 5 (6)

e-/e+ source & pre-pre-injector 1(7)

Total 132

*: low power version with 1e34 cm^-2/s-1 in each of 4 IPs(1): wall power efficiency: power converters: 95%; klystron efficiency: 65%; transmission losses 7%; overall 55% (from the LHeC design report); including RF feedback margin(2): 60% of LHeC ; cryo power depends on cavity Q0 (34 kW at 2 K for 1200 cavities with Q0 =2.5e10)(3): from LHeC ring-ring magnet design; power for 1 magnet (5.5 m, 0.075 T) = 400 W; assuming 2x80 km of magnets at 0.065 T (dipole field for 175 GeV beam energy)(4): TLEP three times more than LHC; maximum capacity for LEP ; reduced by a factor of 2 for low power(5): as for LHC (see appendix)(6): conservative estimate scaled from higher-energy proton operation(7): L. Rinolfi, power of LPI, private communication Mike Koratzinos & F.Z.

cost - LEP experience

total cost of TLEP = LEP cost x 3 x total Swiss inflation since 1990 (1.2?) = 4.7 GCHF

Source:G. Bachy, A. Hofmann, S. Myers, E. Picasso, G. Plass, “The LEP Collider – Construction, Project Status and Outlook,” Part. Acc. 1990, Vol. 26, pp. 19-32

Swiss annual inflation oscillating around 1.0

TLEP cost breakdown – extremely rough (GEuro)TLEP

Bare tunnel 3.1 (1)

Services & Additional infrastructure (electricity, cooling, ventilation, service cavern, RP, surface structure, access roads)

1.0(2)

RF system 1.0 (3)

Cryo system 1.0 (4)

Vacuum system & RP 0.5(5)

Magnet system for collider & injector ring 0.8(6)

Pre-injector complex SPS reinforcements 0.5

Total 7.9

(1): J. Osborne, Amrup study(2): very rough guess, conservative escalated extrapolation from LEP(3): B. Rimmer, SRF cost per GeV or per Watt for CEBAF upgrade, 2010(4): ½ LHC system [also, possibly some refurbished LHC plants could be reused](5): factor 2.5 higher than KEK (K. Oide) estimate for 80 km ring(6): 24,000 magnets for collider & injector; cost per magnet 30 kCHF (LHeC); 10% added; no cost saving from mass production assumedNote: detector costs not included

preliminary – not endorsed by anybody

TLEP cost – 3rd estimate (Shiltsev’s L.E.P.1/2 law)

cost [𝐺$ ]=2 ( 𝐿10 km )

1 /2

+10 ( 𝐸1TeV )

1 /2

+2 ( 𝑃100MW )

1 /2

[Shiltsev rule for US vs EU accounting]

→UScost=14.7G $

→EU cost=5.9GEuro

cost LEP scaling conservative breakdown L.E.P. ½ formula

[GEuro] ~4.5 7.9 5.9

TLEP cost-estimate summary

using 100 km, 240 GeV, 300 MW

U. Chicago Workshop , Feb 25-26, 2013

construction - LEP experience

<6 years

G. Bachy, A. Hofmann, S. Myers, E. Picasso, G. Plass, Part. Acc. 1990, Vol. 26, pp. 19-32

G. Bachy, A. Hofmann, S. Myers, E. Picasso, G. Plass, Part. Acc. 1990, Vol. 26, pp. 19-32

installation - LEP experience

over ~3 years with much less people than for LHC LS1

TLEP/LEP3 key issues

SR handling and radiation shielding optics effect of energy sawtooth

[separate arcs?! (K. Oide)] beam-beam interaction for large Qs

and significant hourglass effect by*=1 mm IR with large acceptance TERA-Z operation (impedance effects

& parasitic collisions)

→ Conceptual Design Study by 2014/15!

see talk by N. Mounet

vertical rms IP spot sizes in nm LEP2 3500

KEKB 940SLC 500 LEP3 320 TLEP-H 220ATF2, FFTB 73 (35), 77SuperKEKB 50ILC 5 – 8CLIC 1 – 2

in regularfont:achieved

in italics:designvalues

LEP3/TLEPwill learn from ATF2 &SuperKEKB

by*:

5 cm→1 mm

merits of a storage ring• better use of beam energy – x240

TLEP-H: DESR= Eb after 240 collisions; in other words, TLEP uses beam energy 240x more efficiently than linear collider where beam energy is spent for 1 collision

• better wall-plug to beam power efficiency – x3

→ together factor ~1000 advantage for TLEP!

arguably ring is greener technology!

There is nothing wrong with change, if it is in the right

direction.

Sir Winston Churchill

VHE-LHC + TLEP L. Rossi

multipurpose tunnel

HE-LHC(20 T)

HE-LHC-LER (0.17→1.5 T)TLEP collider (0.07 or 0.05T) TLEP injector (0.007→0.05/7 T)

20 mm thick shield around cableGaps: 2 x V30xH60 mm

transmission line magnet(B. Foster, H. Piekarz)

super-resistive cable

personal conclusions• need to pursue vigorous accelerator R&D to be

ready to propose new project by 2017/18 • TLEP and VHE-LHC are exciting options with large

synergies• TLEP excellent in terms of energy & luminosity,

and extendable towards VHE-LHC, preparing ≥50 years of e+e-, pp, ep/A physics at highest energies

• TLEP comes for “free” (tunnel, magnets, & detectors “the same” as for VHE-LHC)

• SuperKEKB will be important TLEP demonstrator!

1980 1990 2000 2010 2020 2030

LHC Constr. PhysicsProto.Design, R&D

HL-LHC Constr. PhysicsDesign, R&D

VHE-LHC Constr.Design, R&D

tentative time line

2040

TLEP Constr. PhysicsDesign, R&D

Physics

LHeC& SAPPHiRE?

Constr. PhysicsDesign, R&D

TLEP/LEP3 events & referencesA. Blondel, F. Zimmermann, “A High Luminosity e+e- Collider in the LHC Tunnel to

study the Higgs Boson,” arXiv:1112.2518v1, 24.12.’11K. Oide, “SuperTRISTAN - A possibility of ring collider for Higgs factory,”

KEK Seminar, 13 February 20121st EuCARD LEP3 workshop, CERN, 18 June 2012A. Blondel et al, “LEP3: A High Luminosity e+e- Collider to study the Higgs Boson,”

arXiv:1208.0504, submitted to ESPG KrakowP. Azzi et al, “Prospective Studies for LEP3 with the CMS Detector,”

arXiv:1208.1662 (2012), submitted to ESPG Krakow2nd EuCARD LEP3 workshop, CERN, 23 October 2012P. Janot, “A circular e+e- collider to study H(125),” PH Seminar, CERN, 30 October 2012ICFA Higgs Factory Workshop: Linear vs Circular, FNAL, 14-16 Nov. ’12A. Blondel, F. Zimmermann, “Future possibilities for precise studies of the X(125)

Higgs candidate,” CERN Colloquium, 22 Nov. 20123rd TLEP3 Day, CERN, 10 January 2013

4th TLEP mini-workshop, CERN, 4-5 April 20135th TLEP mini-workshop, 25-26 July 2013, Fermilab https://tlep.web.cern.ch https://cern.ch/accnet

HE-LHC &VHE-LHC events & references

R. Assmann, R. Bailey, O. Brüning, O. Dominguez, G. de Rijk, J.M. Jimenez, S. Myers, L. Rossi, L. Tavian, E. Todesco, F. Zimmermann, “First Thoughts on a Higher-Energy LHC,” CERN-ATS-2010-177

E. Todesco, F. Zimmermann (eds), “EuCARD-AccNet-EuroLumi Workshop: The High-Energy Large Hadron Collider,” Proc. EuCARD-AccNet workshop HE-LHC’10 , Malta, 14-16 October 2010, arXiv:1111.7188 ; CERN Yellow Report CERN-2011-003HiLumi LHC WP6 HE-LHCJoint Snowmass-EuCARD/AccNet-HiLumi meeting `Frontier Capabilities for Hadron

Colliders 2013,‘ CERN, 21-11 February 2013

https://cern.ch/accnet

http://hilumilhc.web.cern.ch/HiLumiLHC/activities/HE-LHC/WP16/

Appendix

• tentative time line w/o LHeC

• example parameters for HL-LHC, HE-LHC, VHE-LHC, TLHeC, VHE-TLHeC

• ERC consolidation grant request THALES

• TLEP work topics & TLEP draft design study proposal

1980 1990 2000 2010 2020 2030

LHC Constr. PhysicsProto.Design, R&D

HL-LHC Constr. PhysicsDesign, R&D

VHE-LHC Constr.Design, R&D

tentative time line w/o LHeC

2040

TLEP Constr. PhysicsDesign, R&D

Physics

(V)HE-LHC parameters – 1

O. Dominguez, L. Rossi, F.Z.

smaller?! (x1/4?)

(V)HE-LHC parameters – 2

O. Dominguez, L. Rossi, F.Z.

(s=100 mb)

numbers for lifetime and average integrated luminosity need to be updated for ~40% higher cross section at 100 TeV

collider parameters TLHeC VHE-TLHeCspecies e± p e± pbeam energy [GeV] 120 7000 120 50000bunch spacing [ms] 3 3 3 3bunch intensity [1011] 5 3.5 5 3.5beam current [mA] 24.3 51.0 24.3 51.0rms bunch length [cm] 0.17 4 0.17 2rms emittance [nm] 10,2 0.40 10,2 0.06bx,y*[cm] 2,1 60,5 0.5,0.25 60,5sx,y* [mm] 15, 4 6, 2beam-beam parameter x

0.05, 0.09 0.03,0.01 0.07,0.10 0.03,0.007

hourglass reduction 0.63 0.42CM energy [TeV] 1.8 4.9luminosity [1034cm-2s-1] 0.5 1.6

parameters for TLHeC & VHE-TLHeC (e- at 120 GeV)

ERC Consolidation Grant Proposal “THALES” –

PI: Rogelio Tomas

includes international network for feeding new ideas, guidance, local support for experimental tests, review & collaboration

draft work topics: TLEP accelerator parameter optimization with regard to

lifetime and luminosity, at different energies, & different tunnels

RF system design, prototyping & integration for collider and accelerator ring

optics design for collider ring including low-beta IRs, off-momentum dynamic aperture, different energies

beamstrahlung: lifetime, steady state beam distribution, dependence on tune etc.

beam-beam interaction with large hourglass effect

emittance tuning studies, errors, tolerances, etc.

optics design and beam dynamics for the accelerator ring, ramping speed etc

impedance budget, CSR, instabilities cryogenics system design

magnets design: collider ring dipole, accelerator ring dipole, low-beta quadrupole

radiation, shielding, cooling for 100 MW SR power

vacuum system design engineering study of 80-km tunnel design of injector complex including e+

source, and polarized e- source machine detector interface, integration of

accelerator ring at detector (s), low-beta quadrupoles, shielding (e.g. against beamstrahlung)?

injection scheme polarization, Siberian snakes, spin

matching, acceleration & storage, polarized sources

(19 September 2012)

TLEP Design Study Proposal(draft)

to be submitted toECFA

a new tunnel for TLEP in the Geneva area?