Legend:(M)EIC@JLab

1 low-energy IP (s ~ 300)2 medium-energy IPs (s <

3000) ELIC = high-energy EIC@JLab

(s = 20000?) (Ep ~ 250 limited by JLab site)

Use CEBAF “as-is” after 12-GeV Upgrade

Ee = 3 – 11 GeV(upgradeable to 20+ GeV)Ep = 20 – 60+ GeV(12 GeV injection energy)(upgradeable to 250 GeV)

Ecm2 = s =

4EeEp

MEIC/ELIC Design Process at JLab

MEIC Design ChoicesAchieving high luminosity Very high bunch repetition frequency (1.5 GHz) Very small β* to reach very small spot sizes at collision points Short bunch length (σz~ β*) to avoid luminosity loss due to

hour-glass effect (unless other mitigation schemes used) Relatively small bunch charge for making short bunch possible High bunch repetition restores high average current and

luminosity

MEICHigh repetition

rateSmall bunch

charge Short bunch

length Small β*

MeRHICLow repetition rate High bunch charge Long bunch length

(but…) Large β* (but…)

VS.

This luminosity concept has been tested at two B-factories very successfully, reaching luminosity above 1034 cm-2/s-1

Current Ideas for a Collider

Energies s luminosity

MEIC@JLab Up to 11 x 60+

240-3000 Close to 1034

Future ELIC@JLab

Up to 11 x 250(22? x 250)

11000 (22000?)

Close to 1035

Staged MeRHIC@BNL IP12/main

ring

Up to 4 x 250

5 x 250?

800-4000

1600(?)-5000(?)

Few x 1032

Close to 1034(?)

eRHIC@BNL Up to 20 x 325 26000 Few x 1033

ENC@GSI Up to 3 x 15 180 Few x 1032

LHeC@CERN Up to 70 x 7000 1960000 1033

Design Goals for Colliders Under Consideration World-wide

Present focus of interest (in the US) are the (M)EIC and Staged MeRHIC versions, with s up to ~3000 and ~5000,

resp.

Both laboratories are working together to get advice on the best steps towards a US Electron-Ion Collider.

Sam Aronson and Christoph Lehmann/Hugh Montgomery have named an international EIC Advisory Committee:

Joachim Bartels Allen Caldwell

Albert De Roeck Walter Henning (chair)

David Hertzog Xiangdong Ji

Robert Klanner Alfred Mueller

Katsunobu Oide Naohito Saito

Uli Wienands

1st meeting Feb. 16, 2009 at SURA headquarters, D.C.

2nd meeting Nov. 2&3, 2009 at Jefferson Lab

3rd meeting around September???, 2010 At BNL???

Concrete design for EIC@Jlab requested by this meeting

Internal reviewed cost estimate requested by this meeting

Near-Term MEIC Design Parameters

Electron Proton

Collision energy

GeV 3 – 11 20 - 60

Ion booster 3–12 GeV, ring accepts 12 GeV injection

Max dipole field

T 6 Not too aggressive after LHC

Max SR power kW/m

20 Factor two beyond best achieved?

Max current A 2 1 ~ max B-factory current, HOM in componentHERA 0.15 A (?) RHIC 0.3 A

RF frequency GHz 1.5 1.5 Use combination of gap (crossing angle) and RF shift to accommodate lower ion energies

Bunch length mm 5 5 6 mm demonstrated in B-factory, 10 cm in RHIC (?)

IP to front face of 1st quad (l)

m +/- 3 to 4

+/- 7

Vertical β* cm 2 2 Keep βmax below ~2 km, with max = l2/*

Crossing angle mrad

100 50 to 150 desired for detector advantages

Luminosity expected to be around 1 x 1034 e-nucleons/s/cm2

around 60x5 GeV2, and be well above 1033 at “s edges”

(M)EIC@JLab: Plan and Deliverables• Accelerator Design “Contract”

– Medium energy with scaled down parameters (ELIC version M.1)

– “Contract” revision (end of 2010), after user workshops and the next EIC AC meeting

• “Design Manual”– A 20 to 30 page document, archived in web– Explanation of high level design choices– Main and secondary parameters, schemes– Major components, and interfaces between them

• Action items– Finish “action items/decision points” in about a week each– Work scope

• Collecting information/references• Performing estimations/calculations if applicable• Formulate a solution/recommendation• Present in ELIC R&D meeting• Write a (minimum) half page on each item for the “design manual”

• Similar Action Item: Detector/IR document

Slide from Yuhong Zhang

MEIC/ELIC Design Process - Status• Near-term design concentrates on parameters that are within state-of-the-art (exception: small bunch length & small vertical * for proton/ion beams)

• Detector/IR design has concentrated on maximizing acceptance for deep exclusive processes and processes associated with very-forward going particles(detect remnants of struck quark & spectator quarks!)

• Exact energy/luminosity profile still a work in progress

• Summer 2010: MEIC design review followed by internal cost review (and finalizing input from user workshops)

• Many parameters related to the detector/IR design seem to be well matched now (crossing angles, magnet apertures/gradients/peak fields, field requirements), such that we do not end up with large “blind spots”.

Electron-Ion Collider – Roadmap beyond JLab user EIC

workshops• EIC (eRHIC/ELIC) webpage: http://web.mit.edu/eicc/• Weekly meetings at both BNL and JLab

• Wiki pages at http://eic.jlab.org/ & https://wiki.bnl.gov/eic• EIC Collaboration has biannual meetings since 2006

• Last EIC meeting: January 10-12, 2010 @ Stony Brook• Next meeting: July 29-31, 2010 @ Catholic University, DC

• Long INT10-03 program @ Institute for Nuclear Theory, centered around spin, QCD matter, imaging, electroweak Sept. 10 – Nov. 19, 2010• Periodic EIC Advisory Committee meetings (convened by BNL & JLab)

After INT10-03 program (2011 – next LRP)• need to produce single, community-wide White Paper

laying out full EIC science program in broad, compelling strokes • and need to adjust EIC designs to be conform accepted

energy-luminosity profile of highest nuclear science impact• followed by an apples-to-apples bottom-up cost estimate comparison

for competing designs, folding in risk factors• and folding in input from ongoing Accelerator R&D, EICAC & community

Backup

Quotes from EICAC Report on Accelerator R&D PrioritiesHighest priority:

Design of JLab EICHigh current (e.g. 50 mA) polarized electron gun Demonstration of high energy – high current recirculation ERL Beam-Beam simulations for EIC Polarized 3He production and acceleration Coherent electron cooling

High priority, but could wait until decision made:Compact loop magnetsElectron cooling for JLab conceptsTraveling focus scheme (it is not clear what the loss in performance would be if it doesn’t work; it is not a show stopper if it doesn’t)Development of eRHIC-type SRF cavities

Medium Priority:Crab cavitiesERL technology development at JLAB

Slide from Steve Vigdor

EIC – JLab User Meetings Roadmap• March 12 + 13 @Rutgers: Electron-Nucleon Exclusive Reactions• March 14 + 15 @Duke: Partonic Transverse Momentum in Hadrons:

Quark Spin-Orbit Correlations and Quark-Gluon Interactions

• April 07, 08, 09 @ANL: Nuclear Chromo-Dynamic Studies• May 17 +18 @W&M: Electroweak Studies• June 04 + 05 @JLab: MEIC Detector Workshop• June 07,08,09 2010 JLab Users Group Meeting

In parallel: MEIC/ELIC design worked out following highest EICAC(Nov. 2010 meeting) recommendation related to

accelerator

Energy-Luminosity profile of EIC design will likely be optimized over time to adjust to novel accelerator science ideas & the nuclear science case For now we assume a base luminosity, say 1034 e-ions/cm2/s Fold in what energies are needed for e.g. L/T separations, imaging, range in Q2 required at fixed x given y cuts, etc. Study what luminosity is required at what energies to optimize the science output, and fold in implications for the detector/acceptance

EIC Project - RoadmapYear CEBAF Upgrade Electron-Ion Colldier

1994 1st CEBAF at Higher Energies Workshop

1996 (LRP) CEBAF Upgrade an Initiative

~2000 Energy choice settled, “Golden Experiments”

1st workshops on US Electron-Ion Collider

2002 (LRP) JLab 12-GeV Upgrade 4th recommendation

Electron-Ion Collider an Initiative

2007 (LRP) JLab 12-GeV Upgrade highest recommendation

Electron-Ion Collider “half-recommendation”

2010 EIC “Golden Experiments”???

2013? (LRP) JLab 12-GeV & FRIB construction highest recommendation?

EIC a formal (numbered) recommendation?

2015 JLab 12-GeV Upgrade construction complete

EIC Mission Need, formal R&D ongoing?

2025? EIC construction complete?