Realization of an Electron-Ion Collider –

BNL ViewSteve Vigdor

Workshop on Perturbative and Non-Perturbative Aspects of QCD at Collider Energies

INT Sept. 13, 2010

“An EIC with polarized beams has been embraced by the U.S. nuclear science com-munity as embodying the vision for reaching the next QCD frontier.”

How can we realize this vision?

Much of 2007 LRP is Well Under Way:

12 GeV upgrade under way – should be complete by 2014-15.

FRIB had successful CD-1 review July 2010. Construction anticipated for ~2013-19.

Much of 2007 LRP is Well Under Way:

DUSEL Preliminary Design Report anticipated to NSF by end of CY2010, presentation to Science Board during 2011.

Technology breakthrough (bunched-beam stochastic cooling) RHIC luminosity upgrade well under way, expected complete in 2013. Detector upgrades complete by 2015.

Next (2013?) LRP Will Benefit from New Long-Range Major Construction Project

1st un-numbered 2007 recommendation:

Accelerator R&D, started with BNL, Jlab resources, now has ONP funding. Need detector R&D funds as well.

However, there are no entitlements ! EIC will be an expensive facility. Major new construction ~2020 in parallel with operations of 3 major facilities (CEBAF, RHIC, FRIB) seems unrealistic. Something will have to give !

What is Needed for NP Community Endorsement of EIC?

Compelling science vision, backed by plausible feasibility simulations for “golden experiments” this workshop and subsequent White Paper (necessary, but not sufficient!)

Clear understanding of critical machine performance requirements

Proofs of principle of beyond state-of-the-art accelerator & detector technology needed to achieve required performance

Credible cost plan for 1st stage that addresses clear subset of science goals at ≲ $500M (OS guidance) for machine + detectors

Timeline and plan that fits with likely ONP funding realities for coming decade (i.e., construction following FRIB, with large contribution from ongoing operations…)

What is Needed for NP Community Endorsement of EIC?

A clear path forward for both BNL and JLab

A sufficiently strong and focused user community, not bifurcated along BNL /JLab fault lines

EIC Important Extension of RHIC Science

Jody Wright

“Condensed matter physics with a force of a different color”

What are the unique quantum many-body manifestations of a non-Abelian gauge theory? Are there lessons for other fundamental (e.g., EW) theories,

that are harder to subject to laboratory investigation?

1) Does asymptotic freedom dense (in color charge) ideal gas QGP? Find “near-perfect” strongly correlated liquid behavior instead !

2) Does rich vacuum structure sphalerons near QGP transition & local symmetry violation? Observed behavior consistent with local (chiral magnetic) P- and CPV; ~ B-violation @ EW phase transition?

3) Do gluon self-interactions universal saturated gluonic matter in hadrons and nuclei? Hints at RHIC, need EIC for definitive answer.

EIC probes weak coupling regime of very high gluon density, where gauge boson occupancy >> 1. All ordinary matter has at its heart an intense, semi-classical force field -- can we demonstrate its universal behavior? Track the transition from dilute parton gas to CGC? “See” confinement reflected in soft-gluon spatial distributions inside nuclei?

EIC Science: Gluon-Dominated Cold Matter in e+A

Search for supersymmetry @ LHC, ILC (?): seeking to unify matter and forces

Electron-Ion Collider: reveal that Nature blurs the distinction

Gluons dominate the soft constituents of hadrons! But density must saturate…

Deep inelastic scattering @ HERA

x < 0.1x < 0.1 x ~ 0.3x ~ 0.3 x ~ 0.8x ~ 0.8

Proton tomography via exclusive

reactions

EIC e + N Important Extension of Nucleon

Structure Studies at HERA, RHIC, JLab,…

DIS, -gluon fusion G(x > few 104)

Bjorken sum rule test to ≲ 2%

SIDIS for low-x sea-quark polarization and transverse spin studies

More luminosity-hungry:

Polarized DVCS, exclusive reactions + LQCD GPD’s map low-x transverse position-dep. PDF’s; Jq from Ji sum rule; Jg?

High-Q2 e+p,d parity viol’n weak coupling running below Z-pole; e LFV?

BNL Planning Assumptions

But need to identify clear science deliverables for lower-s 1st facility stage…

Strongest science case made for the eventual full EIC: e+A for low-x gluon densities, probing conjectured universal saturation surface ( need HI beams, s > 100 GeV, far forward coverage in both e and A directions) e+N DIS & SIDIS for nucleon spin structure in gluon-dominated regime, TMD’s, etc. ( need polarized beams) deep exclusive e+p for GPD’s, (2+1)-D imaging of proton wave fcn. ( need L ~ 1034, high-precision detectors) EW e+N program likely to still be relevant in mid-2020’s parton interactions & hadronization in cold matter

BNL Planning Assumptions

Work on plan to allow straightforward upgrade path from 1st stage, but to incorporate starts on as much of the science program as possible in 1st stage (needed to keep strong user community engaged recent design advances)

Fully utilize RHIC A, p beams and infrastructure

Utilize RHIC detector infrastructure, halls, subsystems as possible to control costs

Utilize BNL LDRD funds plus RHIC R&D funds to jump-start accelerator and detector R&D where possible

Work with JLab as possible to arrange collaborative approach to LRP

eSTAR

ePHEN

IX

eRHIC Design Under Active Consideration

2 SRF linac1 -> 5 GeV per pass4 (6) passes

Vertically separatedrecirculating passes.# of passes will be chosento optimize eRHIC cost C

oherent

e-cooler5 mm

5 mm

5 mm

5 mm

20 GeV e-beam

15 GeV e-beam

10 GeV e-beam

5 GeV e-beam

Com

mon

vacu

um

ch

am

ber

Gap 5 mm total0.3 T for 30 GeV

eRHIC detector

inje

ctor

RHIC: 325 GeV p or 130 GeV/u Au with DX magnets

removed

© V. Litvinenko

eRHIC-I eRHIC: energy of electron beam is

increased from 5 GeV to 30 GeV by building up the

linacs

Vis-à-vis earlier MeRHIC design, this allows for:

more IP’s

reusing infra-structure + det. components for STAR, PHENIX?

reduced cost

easier up-grade path

minimal environmental impact concerns

IR design to reach 1034 lumi-nosity

1.27 m beam high

30 GeV e+ ring

30 GeV ERL 6 passes

HE ERL passes

LE ERL passes

30 25 20 15 10 5 GeV

© V. Litvinenko

Modified eRHIC

Design Improved

Luminosity Achieve *=5 cm with 200 T/m LARP SC quads No e bend near detector, 10 mrad hadron beam crossing angle

Can eventually cover s from 80-160 GeV with above L, 30-200 GeV with > 2 1033 cm2s1

e+A luminosities per nucleon very similar 1st stage e energy will depend on cost

Pursuing Aggressive R&D on Critical Technologies

Developing high-current electron ERL (20 MeV) with RHIC R&D funds; 704 MHz SRF cavities for ERL with HEP funding via BNL-SBU CASE.

Developing proof-of-principle of Gatling Gun approach to multi-cathode high-current (eventually ~50 mA) polarized e gun with BNL LDRD funds.

Also laser system for polarized gun with LDRD funds.

Gap 5 mm total0.3 T for 30 GeV

Pursuing Aggressive R&D on Critical Technologies

Aiming for ~2014 proof-of-principle demo of Coherent e Cooling for hadron beams @ RHIC, aided by BNL LDRD and Program Devel. Funds + pending ONP proposal (joint with Jlab and Tech-X)

Prototyping small-gap dipole and quadrupole magnets and vacuum chambers for compact recirculation arcs on electron beam, with BNL LDRD funds.

Also exploring relevance of CeC for improving RHIC p+p luminosities and ERL-driven options for X-ray FEL (LDRD).

All in addition to ongoing work on lattice, IR and detector design, plus beam & spin dynamics and beam-beam simulations.

Anticipated FY11 Milestones Oct. 2010: STAR, PHENIX submit decadal plans, including assessment of detector adaptation to e+p and e+A collisions

Oct. 2010: Begin LDRD funding for BNL/Columbia/IPHC collab’n on CMOS Active Pixel Sensor R&D for EIC vertexing

Q2 FY11: Launch competitive (not site-specific!) EIC detector R&D program, with independent review committee, using either RHIC R&D or ONP funds (under discussion…)

Q2 FY11: Workshop on strategy for RHIC future – decadal planning for A+A, p+p, d+A, e+p, e+A, detector upgrades, …

Q2 FY11: External review of eRHIC design

Q4 FY11: External review of eRHIC cost estimation, as function of s reach

Q4 FY11: Community-wide EIC science White Paper, to make compelling case to rest of NP community and DOE

Anticipated FY12 Milestones

Q2 FY12: JLab, BNL, EIC Collaboration, EICAC, DOE define facility design down-select criteria and review mechanism.

N.B. If both labs are not willing to participate in a down-selection prior to LRP, then we must at least go into LRP with clear mechanism for making a subsequent selection.

Q4 FY12: Update EIC Science White Paper with realizable EIC design(s), including cost range, performance goals, science deliverables and upgrade paths, in preparation for (assumed) Spring 2013 LRP resolution meeting.

Quotes from Nov. 2009 EICAC Report on Science and Community Convergence

• The [Fall 2010] INT Program should be used to articulate the theoretical motivation, but also to compare those goals with reality by examining the sensitivities of simulated experiments. An outcome should be the science / machine matrix discussed earlier. At the conclusion of the INT program, we can anticipate some follow-up event(s) in 2011 where the joint community agrees on the theme of a final White Paper.

• The EIC Community appears to be made of two sub-groups, roughly associated with the BNL or JLab concepts for the machine…it is our opinion that there remains time for vigorous debate about scientific options and priorities; however, for full consideration at the next LRP, one coherent, joint-QCD-community request should be made.

• To progress further, some assurance from lab managements would be useful, stating that, which ever facility scheme will be chosen in the end of the evaluation process, both laboratories are committed to making it a success together.

Backup Slides

The √s vs. luminosity landscapeThe √s vs. luminosity landscape

2121

semi-inclusive DISsemi-inclusive DIS

inclusive DISinclusive DIS

DiffractionDiffraction

electro-weakelectro-weak

4x1004x10010x1010x100 0 4x2504x250

20x10020x100 20x25020x250

exclusive DIS (DVCS)exclusive DIS (DVCS)

exclusive DIS (PS & VM)exclusive DIS (PS & VM)

HERA

Minimum luminosities to “get in the game” -- from Elke Aschenauer

30x32530x325

EIC should HERA +

2 orders of magnitude in luminosity

polarized p, 3He beams

heavy-ion beams

eRHIC IRs, β*=5cm, l*=4.5 m

30 GeV e- beam

325 GeV p

beam

325 GeV p

beam

Spin

-Rota

tor

10 mrad

L=1.4x1034cm-2s-1, 200 T/m gradient

0.45

m

90.m

Nb3Sn

200 T/m

Star detector©Dejan Trbojevic

Plan to use newly commissioned LARP Ni3Sn SC quads with 200 T/m gradient

The first Nb3Sn Long Quadrupole (LQS01) designed and fabricated by the US LHC Accelerator Research Program (LARP) reached its target gradient of 200 T/m during the first test. LQS01 is a 90 mm aperture, 4 meter long quadrupole with Nb3Sn coils made of RRP 54/61 strand

Accelerator R&D working with detector R&D

parameter unit spec comment

wavelength nm 780

repetition rate kHz 70414.07 MHz / 20 cathodes

pulse energy at photocathode uJ 2.8

assuming QE=0.2%

average laser power at cathode W 2

assuming QE=0.2%

average laser power W 4

pulse width nsec 1.2GaussianFWHM

jitter psec 50

amplitude stability 1.00E-04

contrast 1.00E-06

Polarized Gun Laser System (LDRD)

• 10 W Erbium doped fiber amplifier system at 1560 nm, frequency doubled in periodically-poled material• CW diode laser + electro-optic modulation for pulse source

• control of pulse shape, low jitter• Two companies proposing designs

• high peak power in the amplifier is the technical challenge

• problem has been solved in similar commercial systems

• cost $100-$200 K

Progress on eRHIC design: Coherent Electron CoolingGeneral EIC R&D item: Over the past three years, we developed an impressive arsenal of analytical- and numerical-tools to predict the performance of a CeC. Joint proposal with Jlab and Tech-X submitted to carry out a Proof of Principle demonstration of coherent electron cooling.

EIC Advisory Committee (to JLab and BNL)

Joachim Bartels (Universitait Hamburg, DESY)Allen Caldwell (Max-Planck Institute for Physics, Munich)Albert De Roeck (CERN) Walter Henning (ANL, Chair) David Hertzog (University of Illinois) Xiangdong Ji (University of Maryland) Robert Klanner (DESY) Al Mueller (University of Columbia) Katsunobu Oide (KEK) Naohito Saito (JPARC) Uli Wienands (SLAC)

Get Good AdviceGet Good Advice

1st meeting 2/16/09. 2nd meeting 11/02/09.

Quotes from EICAC Report on Facility Design & Strategy• The EICAC is impressed with the…work…on accelerator designs since the

last meeting… the two laboratories are at very different levels of design maturity.

• It is the growing view of several members of EICAC that as soon as possible a “down select” should be made…there is much R&D that needs to be done…addressing all the challenges of both [designs] is expensive and perhaps unwarranted. The highest priority on the facility side is to develop the JLAB design to a stage similar to where the BNL design is at present.

• In terms of strategy…the EICAC feels that the proponents might consider aiming for the EIC facility from the beginning, with a medium-range performance scope and future upgrade opportunities.

• It may…be wise to consider the possibility of more than one interaction region to satisfy these different [science and detector] requirements. This would also provide a natural way for different physics communities to group themselves.

Quotes from EICAC Report on Accelerator R&D Priorities

Highest 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

Quotes from EICAC Report on Detector Development

• The EICAC feels that there is no need at this point to carry out detailed GEANT simulations, but rather to study responses based on parameterizations. The trade-off between the resolutions and acceptances of the detectors on the one hand, and luminosity, polarization and beam energies on the other hand for the physics can be understood with these kinds of studies.

• In a prioritized way, R&D suggested for the near term should begin to address the following areas: -Low-mass vertex-tracker/tracker, and integration of a TRD detector in the tracker-particle identification at mid-rapidity for particles with momenta up to 4 GeV, e.g., using DIRC technology-low cost photon detection, e.g., SiPMs-ion polarimeters

• The EICAC considers it important that the detector R&D efforts are conducted jointly for MeRHIC and MEIC. Contacts with other communities like LHeC are also strongly encouraged.

Quotes from EICAC Report on Path to “Down Select”

• [At Fall 2010 INT Workshop]: i) For each of the two directions, it would be very useful to prepare a concrete list of the requested measurements (including the scientific motivation, kinematic region, required accuracy etc.); and/or ii) each of the two groups should investigate to what extent their scientific goals could be reached by the other machine (i.e. 'proton imaging' etc by the BNL design, 'saturation' etc by the JLab version).

• …it would be useful to define a few sets of parameters (energy, luminosity, polarization) based on the expectations from each machine for simulation studies. Available space at the IR should also be defined. These can then be put together with detector designs to understand the physics capabilities for the signature (and other) measurements. These results should then be put together with expected cost, time scale for the accelerator development, and possibilities for future upgrades to higher energies and luminosity in determining which accelerator option is to be backed by the community.