The LHeC and Future ep Collisions at CERN

Frank ZimmermannLHeC Workshop , Chavannes-de-Bogis

20 January 2014

Work supported by the European Commission under Capacities 7th Framework Programme, Grant Agreement 312453

J. Osborne

Many contributors to accelerator study: Jose Abelleira, Chris Adolphsen, Husnu Aksakal, Rob Appleby, Mei Bai, Desmond Barber, Nathan Bernard, Sergio Bertolucci, Alex Bogacz, Frederick Bordry, Luca Bottura, Chiara Bracco, Hans Braun, Stephen Brooks, Oliver Brüning, Eugene Bulyak, Helmut Burkhardt, Rama Calaga, Swapan Chattopadhyay, Ed Ciapala, Kenan Ciftci, Reina Ciftci, John Dainton, Anders Eide, Emre Eroglu, Miriam Fitterer, Hector Garcia, Brennan Goddard, Yue Hao, Friedrich Haug, Bernhard Holzer, Erk Jensen, Miguel Jimenez, John Jowett, Dmitry Kayran, Max Klein, Peter Kostka, Vladimir Litvinenko, Karl Hubert Mess, Attilio Milanese, Steve Myers, Zafer Nergiz, Ed Nissen, John Osborne, Dario Pellegrini, Tatiana Pieloni, Abrahan Pinedo, Alessandro Polini, Vadim Ptitsin, Louis Rinolfi, Lucio Rossi, Giovanni Rumolo, Stephan Russenschuck, Jake Skrabacz, Daniel Schulte, Ilkyoung Shin, Peter Sievers, Mike Sullivan, Saleh Sutansoy, Hugues Thiesen, Luke Thompson, Rogelio Tomas, Davide Tommasini, Dejan Trbojevic, Joachim Tückmantel, Alessandra Valloni, Alessandro Variola, Ferdinand Willeke, Vitaly Yakimenko, Fabian Zomer, … ++

LHeC CDR published in 2012 (~600 pages)

RR LHeC:new ring in LHC tunnel,with bypassesaround experiments

LR LHeC:recirculatinglinac withenergy recovery

Large Hadron electron Collider

baselineconfiguration

CDR performance targets

e- energy ≥60 GeV (2x HERA)luminosity ~1033 cm-2s-1 (25x HERA)total electrical power for e-: ≤100 MWoperation simultaneous with LHC pp physics

e+p collisions (with similar luminosity?)e-/e+ polarizationdetector acceptance down to 1o

two 10-GeV SC linacs, 3-pass up, 3-pass down; 6.4 mA, 60 GeV e-’s collide w. LHC protons/ions

(C=1/3 LHC allows for ion clearing gaps)

A. Bogacz, O. Brüning, M. Klein, D. Schulte, F. Zimmermann, et al

LHeC Linac-Ring ERL layout

ion gaps & circumferencegap turn 1gap turn 2gap turn 3

gap turn 1gap turn 2gap turn 3

CLHeC=CLHC/n

future: CLHeC+=CFHC/m

IP#1

IP#2

DC=k CLHeC

LHC

FHC

m, n (=3), k: integer

Alice

J.Osborne / A.Kosmicki CERN/GS

Prevessin site

LHC

TI2

LHeC baseline: underground layout / integration with LHC;example: Point 2

ERL Linac Optics

flexible momentum compaction cell; tuned for small beam size (low energy) or low De (high energy)

A. Bogacz

ERL Arc Optics

to be studied: alternative based on FFAG-type arcs à la eRHIC

Non-colliding proton beam

colliding proton beam

Electron beam

Synchrotron radiation

High-gradient SC IR quadrupoles based on Nb3Sn for colliding proton beam with common low-field exit hole for electron beam and non-colliding proton beam

detector integrated dipole: 0.3 T over +/- 9 m

S. Russenschuck

Inner triplets

Exit hole for electrons & non-colliding protons

Inner triplets

Q1Q2

Q2

Q1

Nb3Sn (HFM46): 5700 A, 175 T/m, 4.7 T at 82% on LL (4 layers), 4.2 K

Nb3Sn (HFM46): 8600 A, 311 T/m, at 83% LL, 4.2 K

46 mm (half) ap., 63 mm beam sep.

23 mm ap.. 87 mm beam sep.

0.5 T, 25 T/m 0.09 T, 9 T/m

LHeC IR layout & SC IR quadrupolesR. Tomas

new design with larger l*

ring-ringee>>ep, be

*<< bp*

ring-linacee≈ep, be

*≈ bp*

minimum e- beta functionand beam sizeslimited by hourglass effect;small crossing angle acceptable;little disruption

much smaller e- emittancesmaller beta functionand beam sizes possible;head-on collision required;significant disruption

; hourglass reduction factor

colliding unequal beams

Dhgepp

pb HHIN

eL

*

, 1

4

1

luminosity of LR collider:

highest protonbeam brightness available(may dependon bunch spacing)

Nb=1.7x1011

eN=3.75 mm

decreasedproton b* function: - reduced l* (23 m → 10 m)- squeeze only one p beam- new magnet technology Nb3Sn

b*p=0.1 m

maximize geometricoverlap factor- head-on collision- small e- emittance

qc=0Hhg≥0.9

(round beams)

average e-

current limited by energy recovery

efficiency

Ie=6.4 mA

HD~1.3D. SchulteLHeC2010

path to 1033 cm-2s-1

LHeC baseline parameters parameter [unit]species e- pbeam energy (/nucleon) [GeV] 60 7000bunch spacing [ns] 25 (50) 25 (50)bunch intensity (nucleon) [1010] 0.1 (0.2) 17beam current [mA] 6.4 860rms bunch length [mm] 0.6 75.5polarization [%] 90 nonenormalized rms emittance [mm] 50 3.75geometric rms emittance [nm] 0.43 0.50IP beta function bx,y* [m] 0.12 0.10

IP rms spot size [mm] 7.2 7.2synchroton tune Qs - 1.9x10-3

LHeC baseline parameters – cont’dparameter [unit]species e- phadron beam-beam parameter x 0.0001 (0.0002)lepton disruption parameter D 6crossing angle 0hourglass reduction factor Hhg 0.91

pinch enhancement factor HD 1.35

c.m. energy ( /nucleon) [GeV] 1300luminosity / nucleon [1033 cm-1s-1] 1.3

BBU: beam stability requires damping (Q~105) detuning helps further (Df/frms~0, or 0.1%) , 802 MHz

D. Pellegrini,D. Schulte

ERL Beam Dynamics

SLC CLIC(3 TeV)

ILC(RDR)

LHeC

Energy 1.19 GeV 2.86 GeV 5 GeV 60 GeV

e+/ bunch at IP 40 x 109 3.72x109 20 x 109 2x109

e+/ bunch before DR inj. 50 x 109 7.6x109 30 x 109 N/A

Bunches / macropulse 1 312 2625 N/A

Macropulse repet. rate 120 50 5 CW

Bunches / second 120 15600 13125 20x106

e+ / second 0.06 x 1014 1.1 x 1014 3.9 x 1014 400 x 1014

X 18X 65

X 6666L. Rinolfi

e+ source requirements

possible e+ source options • recycle e+ together with energy, multiple use,

damping ring in SPS tunnel w t~2 ms • Compton ring, Compton ERL, coherent pair

production, or undulator for high-energy beam• 3-ring transformer & cooling scheme

accumulator ring (N turns)

fast cooling ring (N turns)

extraction ring (N turns)

(Y. Papaphilippou)

(E. Bulyak)

(H. Braun, E. Bulyak,T. Omori,V. Yakimenko)

(D. Schulte)

LHeC baseline parameters incl. e-Pb parameter [unit]species e- p Pb (ult.)beam energy (/nucleon) [GeV] 60 7000 2760bunch spacing [ns] 25 (50) 25 (50) 100bunch intensity (nucleon) [1010] 0.1 (0.2) (0.4) 17 2.5beam current [mA] 6.4 860 10.5rms bunch length [mm] 0.6 75.5 75.5polarization [%] 90 none Nonenormalized rms emittance [mm] 50 3.75 ~1.4geometric rms emittance [nm] 0.43 0.50 0.5IP beta function bx,y* [m] 0.12 0.10 0.10

IP rms spot size [mm] 7.2 7.2 7.2synchroton tune Qs - 1.9x10-3 1.9x10-3

LHeC baseline parameters incl. e-Pb – cont’dparameter [unit]species e- p Pb (ult.)hadron beam-beam parameter x 0.0001 (0.0002) 0.0001lepton disruption parameter D 6 0.3crossing angle 0 0hourglass reduction factor Hhg 0.91 0.91

pinch enhancement factor HD 1.35 1.0

c.m. energy ( /nucleon) [GeV] 1300 814luminosity / nucleon [1033 cm-1s-1] 1.3 0.1

system wall plug powercryogenics (Q0=2.5x1010) 21 MW (P∞1/Q0)RF operation & microphonics control

24 MW

addt’l RF power to compensate SR losses (12 MW at 6.4 mA at rdip=764 m ([R=1 km with F=76.4%])

24 MW (P∞Ie/rdip2)

injector 7 MWmagnets (arcs + IR) 4 MWtotal ~80 MW

electrical power budget

J. Skrabacz,2008

racetrack shape with acceleration in one or both straight sections; shape optimized for minimum construction (& operation) cost

Single or double acceleration? How many revolutions for optimum energy gain?Can we reduce emittancegrowth and cost?

choice of baseline layout

input cost figures (2008 study)rough estimate for cost / (unit length) extracted from XFEL, ILC and ELFE designs:linac: 160 k$/m

- with an effective gradient of 11.8 MV/m (XFEL)arc section: 50k$/m

- 300 M$ per ILC Damping Ringdrift straight: 10k$/m

- vacuum + perhaps some diagnostics?, taken as ~20% of cost of arc section from ELFE design

ILC tunnel cost: ~5k$/m- already taken to be included in above numbers- otherwise important only for the straight drifts,

potentially raising the drift cost to 15k$/m

construction cost at 60 GeV

single linac

double linac

2-3 circulations are optimum at 60 GeV(w/o restraining energy loss)

~400 MEuro

J. Skrabacz(assuming 15 MV/m)

each pointhas cost-optimizedlengths of linac,arc, and drifts

3 turns2.5 turns

effective cost = construction cost + SR-dependent operation cost= construction cost+ l DESR

effective cost

[ ] l = M$/GeV

value for weight factor l?

Ie=6.4 mA with DE=1 GeV over 1 year (107 s) → 36 GWh SRF electrical power; over 10 yrs: 360 GWhelectricity cost ~50 $/MWh → ~20 M$ in total

l=10-100 M$/GeV!

optimized cost vs energyJ. Skrabacz

“optimum of optimum”cost increasesabout linearly withenergy

adding weight parameter l in units of M$/(GeV energy loss)to limit operating cost

J. Skrabacz, “Optimizing Cost and Minimizing Energy Loss in the Recirculating Race-Track Design of the LHeC Electron Linac,”U.M., CERN REU, 2008

opt. circumference vs energyJ. Skrabacz

total circumferencealso increaseslinearly withenergy

better shapes?J. Skrabacz

“ballfield” designs with additional shape parametersmight reduce energy loss, emittance growth, or cost

extreme ballfields vs racetrack

racetrack looks best after all

J. Skrabacz60 GeV

cost-optimized #turns vs energyJ. Skrabacz

above 60 GeVsingle recirculation may be optimum!above ~140 GeVsingle linac!

l=100

beam energy

l=10 M$/GeV

l=100 M$/GeV

20 GeV 4.5 3.540 GeV 3.5 2.560 GeV 3.5 1.580 GeV 3.5 1.5100 GeV 2.5 1.5120 GeV 2.5 1.5140 GeV 1.5 0.5

pulsed w/o energy recovery

140-GeV linacinjector dump

IP7.9 km

Ee=140 GeV, <Ie>=0.27 mA, L≈4x1031 cm-2s-1 , extendable in energy

0.4 km

final focus

V. Litvinenko, 2nd LHeC workshopDivonne 2009cw with 2-beam energy recovery

L≈1035 cm-2s-1 , no SR, efficient ER, CLIC expertise, 2 linacs

single-pass higher energy linacs

• L ≥ 1034 cm-2s-1 needed for ep Higgs physics• higher brightness p beams for HL-LHC (LIU)• further squeezing bp* looks possible• higher e- current & smaller e- emittance

- 6.4 mA → 12.8 or 25.6 mA(Cornell ERL: 100 mA; BNL eRHIC ERL: 50 mA (pol.))

- ge = 50 mm → 20 mm at 1 nC bunch charge(LCLS, PITZ sources ≤ 1 mm)

- we still had 20 MW power margin till 100 MW- trend towards SC cavities with higher Q0

(→ lower cryo power)

higher luminosity

normalized emittance for 1 nC has been reduced from tens of mm to 1 mm

0.0

5.0

10.0

15.0

20.0

25.0

30.0

1979 1984 1989 1994 1999 2004

Year

No

rma

lize

d R

MS

Em

itta

nc

e a

t 1

nC

(m

m-m

rad

) Thermionic Injectors

PhotoinjectorsSLAC

Boeing

BNL

LANL - APEX

LANL – AFELBNL/UCLA/SLAC

BNL/KEK/SHIBNL/UCLA/SLAC

PITZ scaling: (nC)m)( 7.0 qn

LCLS scaling: (nC)m)( 1 qn

LHeCbaseline50 mm

Bruce Carlsten, SPACE CHARGE 2013

higher-Q0 Nb SRF cavities

Q0=1011

Q0=3x1010

18 MV/m 4 MV/m

world-record Q0 for a multi-cell cavity of the Cornell ERL, June 2013

Horizontal Test Cryostat

LHeC baseline considers Q0=2.5x10 10 at lower fRF

M. Liepe & S. Posen

34Future Circular Collider StudyMichael BenediktP5 Meeting 16 December 2013

potential of Nb3Sn SRF cavities

Data from P. Dhakal

R&D progressingat JLAB& Cornell

Robert Rimmer, JLAB

LHeC target

LHeC Higgs factory (LHeC-HF) parameters parameter [unit]species e- pbeam energy (/nucleon) [GeV] 60 7000bunch spacing [ns] 25 25 bunch intensity (nucleon) [1010] 0.1 → 0.4 17→ 22beam current [mA] 6.4 → 25.6 860 → 1110normalized rms emittance [mm] 50 → 20 3.75 → 2.5geometric rms emittance [nm] 0.43 → 0.17 0.50 → 0.34IP beta function bx,y* [m] 0.12 → 0.10 0.10 → 0.05

IP rms spot size [mm] 7.2 → 4.1 7.2 → 4.1lepton D & hadron x 6 → 23 0.0001→ 0.0004hourglass reduction factor Hhg 0.91→ 0.70

pinch enhancement factor HD 1.35

luminosity / nucleon [1033 cm-1s-1] 1.3 → 16

SAPPHiRE: Small Accelerator for Photon-Photon Higgs production using Recirculating Electrons

Reconfigured LHeC

SAPPHiRE gg Higgs factory100 MW total wall-plug power, Lgg ~6x1032 cm-2s-1

(1 year = 107 s at design luminosity)

machine LHeC LHeC-HF SAPPHiRE

luminosity [1034 cm-2s-1]

0.1 (ep) 2 (ep) 0.06 ( gg>125 GeV)

Higgs production cross section

~200 fb ~200 fb >1.7 pb

no. Higgs/yr 2k 40k >10k

LHeC ep & gg Higgs factories

SRF/ERL test facility at CERN

Alessandra Valloni

important milestone and key to future projects

up to 4 cryo-modulesbeam energy up to 1 GeV

beyond 2030?

“For time and the world do not stand still…”

John F. Kennedy

RECFA - Budapest– 5th October 2013

15 T 100 TeV in 100 km20 T 100 TeV in 80 km

FCC (Future Circular Colliders)

CDR and cost reviewfor the next ESU (2018)(including injectors)

FCC - 80-100 km tunnel infrastructure in Geneva area – design driven by pp-collider (FHC) requirements

with possibility of e+e- (TLEP) and p-e (FHeC)

F. Bordry

e- energy = 60, 120, 250 GeV p energy = 50 TeVIP spot size determined by pe- current from FLC (SR power ≤ 50 MW)#IPs = 1 or 2

key parameters for FHLC/FHeC

collider parameters e± scenarios protonsspecies e± e± e± pbeam energy [GeV] 60 120 250 50000bunch spacing [ms] 0.125 2 33 0.125 to 33bunch intensity [1011] 3.8 3.7 3.3 3.0beam current [mA] 477 29.8 1.6 384 (max)rms bunch length [cm] 0.25 0.21 0.18 2rms emittance [nm] 6.0, 3.0 7.5, 3.75 4, 2 0.06, 0.03bx,y*[mm] 5.0, 2.5 4.0, 2.0 9.3, 4.5 500, 250sx,y* [mm] 5.5, 2.7beam-b. parameter x 0.13 0.050 0.056 0.017hourglass reduction 0.42 0.36 0.68CM energy [TeV] 3.5 4.9 7.1luminosity[1034cm-2s-1] 21 1.2 0.07

preliminary (!) parameters for FHeC

http://indico.cern.ch/e/fcc-kickoff

FCC Kick-off Meeting inGeneva next month

Infrastructure, cost estimates

P. Lebrun

VL Hadron collider

D. Schulte

Hadron injectors

B. Goddard

e- p option Integration aspects O. Brüning

Future Circular Colliders - Conceptual Design StudyStudy coordination, host state relations, global cost estimate

M. Benedikt, F. Zimmermann

e+ e- collider

J. Wenninger

High Field Magnets

L. BotturaSupercon-ducting RFE. Jensen

CryogenicsL. TavianSpecific

Technologies(MP, Coll, Vac,

BI, BT, PO)JM. Jimenez

Physics and experiments

Hadron physic Experiments, infrastructureA. Ball, F. Gianotti,

M. Mangano

e+ e- exper., physics

A. Blondel J.Ellis, P.Janot

e- p physics +M. Klein

Operation aspects, energy efficiency, OP & mainten., safety, environment.

P. Collier

Planning (Implementation roadmap, financial planning, reporting)F. Sonnemann

Team preparing FCC Kick-Off & Study

contributors to LHeC design effort

study coordinator deputy coordinator

looking for int’l co-conveners!

PSB PS (0.6 km)SPS (6.9 km)

HL-LHC

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

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

possible long-term strategy

LHeC/FHeC: e± (60-250 GeV) – p (7 and/or 50 TeV) collisions !

≥50 years e+e-, pp, e±p/A physics at highest energies

LHeC & SAPPHiRE?

LHC (26.7 km)

LHeC as TLEP injector?

LHeC-FHC collider if TLEP is not constructed?!

FHeC as TLEP-FHCCollider ?!

LHC Constr. PhysicsProto.Design, R&D

HL-LHC Constr. PhysicsDesign, R&D

VHE-LHC/FHC

Constr.Design, R&D

TLEP? Constr. PhysicsDesign, R&D

Physics

LHeC/SAPPHiRE Constr. PhysicsDesign, R&D

possible long-term time line

FHeC Constr.Design, R&D Physics

PhysicsConstr.+ LHeC-FHC

(with TLEP)

(w/o TLEP)

LHeC design matured over past 6 years; CDR published in 2012; ERL baseline looks conservative

design parameters (circumference, beam energy, RF frequency, number of passes, etc.) can be further optimized for cost and/or performance

new high luminosity parameters for Higgs physicsLHeC-based gg collider Higgs factory (SAPPHiRE) LHeC compatible with long-term strategy (FCC)

• LHeC/SAPPHiRE RF & cryo identical to TLEP/FLC’s – can be reused; remaining LHeC can serve as TLEP injector

•FHeC: combination of TLEP/FLC and VHE-LHC/FHC with highest-energy highest-luminosity e±p collisions; direct LHeC-FHC collisions as backup

summary

thank you for your attention