MEIC:A Medium Energy Electron Ion Collider

at Jefferson Lab

QCD and Hadron Physics, LanzhouMarch 30, 2013

R. D. McKeownJefferson LabCollege of William and Mary

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Outline

• Introduction to Jefferson Lab

• Motivation for Electron Ion Collider

- Science goals

- Requirements and specifications

• MEIC design

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Jlab: A Laboratory for Nuclear Science

FundamentalForces & Symmetries

Hadrons from Quarks

Medical Imaging

Quark Confinement

Structure of Hadrons

Accelerator S&T

Nuclear Structure

Theory and Computation

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Current Jefferson Lab Accelerator Complex

A B C CEBAF Large Acceptance Spectrometer (CLAS) in Hall B

Cryomodules in the accelerator tunnel

Free Electron Laser (FEL)

Superconducting radiofrequency (SRF) cavities

Hall D (new construction)

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12 GeV Upgrade Project

Scope of the project includes: • Doubling the accelerator beam energy• New experimental Hall and beamline• Upgrades to existing Experimental Halls

Maintain capability to deliver lower pass beam energies: 2.2, 4.4, 6.6….

New Hall

Add arc

Enhanced capabilitiesin existing Halls

Add 5 cryomodules

Add 5 cryomodules

20 cryomodules

20 cryomodules

Upgrade arc magnets and supplies

CHL upgrade

Upgrade is designed to build on existing facility: vast majority of accelerator and experimental equipment have continued use

The completion of the 12 GeV Upgrade of CEBAF was ranked the highest priority in the 2007 NSAC Long Range Plan.

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Hall D – exploring origin of confinement by studying exotic mesons

Hall B – understanding nucleon structure via generalized parton distributions

Hall C – precision determination of valence quark properties in nucleons and nuclei

Hall A –form factors, future new experiments (e.g., SoLID and MOLLER)

12 GeV Scientific Capabilities

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Present expectation (subject to rebaseline review):

12 16-month installation May 2012 - May Sept 2013

Hall A commissioning start Oct 2013 Feb 2014

Hall D commissioning start April 2014 Oct 2014

Halls B & C commissioning start Oct 2014 Oct 2015

Project Completion Dec 2016

FY12: reduction of $16MFY13: Pres Request – no restoration Rebaseline in progress

Next DOE Project ReviewMay, 2013

12 GeV Upgrade Project Schedule

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Hall D & Counting House

12 GeV Project Status

Hall D Drift Chamber

• Installation in all 4 Halls has begun

• Challenges with superconducting magnets for experiments• All 7 magnets under contract• Schedule delay a concern for two contracts• Hall D solenoid cool-down is underway

• Upgrade Project 73% Complete, 85% Obligated

• Accelerator commissioning begins October 2013

• Beam to Hall A in 2nd Quarter of FY14

• Beam to Hall D in 1st Quarter of FY15

Hall D Interior

Hall C DipoleMagnet Coil

SC Magnet Conductor Press

FY06FY07

FY08FY09

FY10FY11

FY12FY13

0

20

40

60

80

100

DO

E O

blig

ate

d (

%)

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Beyond 12 GeV Upgrade

• Super BigBite Spectrometer(Approved for FY13-16 construction)- high Q2 form factors - SIDIS

• MOLLER experiment (MIE – FY15-18?)

- Standard Model Test

• SoLID Chinese collaboration CLEO Solenoid

• Enhancements of equipment in B, C, D (Leverage external investments)

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JLab12: 21st Century Science Questions

• What is the role of gluonic excitations in the spectroscopy of light mesons? Can these excitations elucidate the origin of quark confinement?

• Where is the missing spin in the nucleon? Is there a significant contribution from valence quark orbital angular momentum?

• Can we reveal a novel landscape of nucleon substructure through measurements of new multidimensional distribution functions?

• What is the relation between short-range N-N correlations, the partonic structure of nuclei, and the origin of the nuclear force?

• Can we discover evidence for physics beyond the standard model of particle physics?

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12 GeV Approved Experiments by PAC Days

More than 7 years of approved experiments

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12 GeV White Paper

arXiv:1208.1244

1 Executive Summary

2 Meson Spectroscopy, Hybrid Mesons & Confinement

3 The Internal Structure of Hadrons

4 QCD and Nuclei

5 The Standard Model and Beyond

6 Appendix A: Experimental Equipment

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Electron Ion Collider

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NSAC 2007 Long-Range Plan:

“An Electron-Ion Collider (EIC) with polarized beams has been embraced by the U.S. nuclear science community as embodying the vision for reaching the next QCD frontier. EIC would provide unique capabilities for the study of QCD well beyond those available at existing facilities worldwide and complementary to those planned for the next generation of accelerators in Europe and Asia.”

• Jefferson Lab and BNL developing facility designs

• Joint community efforts to develop science case white paper (2013)

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2010 NRC Decadal Study

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Recent Documents

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12 GeV

• With 12 GeV we study mostly the valence quark component

• An EIC aims to study gluon dominated matter.

The Landscape of EIC

mEIC

EIC

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EIC Science (I)

EIC will complete our knowledge of the nucleon through exploration of the gluon-dominated regime at low x.

• How much spin is carried by gluons?• Does orbital motion of sea quarks contribute to spin?

- Generalized parton distributions (GPD)

- Transverse momentum dependent (TMD) distributions• What do the parton distributions reveal in transverse

momentum and coordinate space?

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EIC Science (II)

Map the gluon field in nuclei• What is the distribution of glue in nuclei?• Are there modifications as for quarks?• Can we observe gluon saturation effects?

Study spacetime evolution of color charges in nuclei• How do color charges evolve in space and time?• How do partons propagate in nuclear matter?• Can nuclei help reveal the dynamics of fragmentation?

Search for physics beyond the standard model

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EIC Requirements

From the 2013 EIC White Paper:

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EIC

The Reach of EIC

JLab12

EMC/E665 HERMES

• High Luminosity 1034cm-2s-1

• High Polarization 70%

• Low x regimex 0.0001

Discovery Potential!

0.0001 0.001 0.01 0.1 11.00E+30

1.00E+31

1.00E+32

1.00E+33

1.00E+34

1.00E+35

1.00E+36

1.00E+37

1.00E+38

x

HERA (no p pol.)

COMPASS

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Polarized Luminosity

x = Q2/ys

(x,Q2) phase space directly correlated with s (=4EeEp) :

@ Q2 = 1 lowest x scales like s-1

@ Q2 = 10 lowest x scales as 10s-1

current data

w/ EIC data

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Polarized Luminosity: SIDIS

Major improvement over present data!

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Medium Energy EIC@JLab

JLab Concept

MEIC:• 3-12 GeV on 20-100 GeV ep/eA collider• fully-polarized, longitudinal and transverse• luminosity: up to few x 1034 e-nucleons cm-2 s-1

Upgradable to higher energies (250 GeV protons)

Pre-booster

Ionsource

Transfer beam line

Medium energy IP

Electron collider ring

(3 to 12 GeV)Injector

12 GeV CEBAF

SRF linacWarm large

booster(up to 20 GeV)

Cold ion collider ring

(up to 100 GeV)

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MEIC Design Report

• Posted: arXiv:1209.0757

• Stable concept for 3 years

Overall MEIC design features:

• Highly polarized (including D)

• Full acceptance & high luminosity

• Minimize technical risk and R&D

“world’s first polarized e-p collider and world’s first e-A collider”

• EPJA article by JLab theory on MEIC science case (arXiv:1110.1031; EPJ A48 (2012) 92)

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Design Features: High Polarization

All ion rings (two boosters, collider) have a figure-8 shape • Spin precession in the left & right parts of the ring are exactly cancelled• Net spin precession (spin tune) is zero, thus energy independent

• Ensures spin preservation and ease of spin manipulation • Avoids energy-dependent spin sensitivity for ion all species• The only practical way to accommodate medium energy polarized deuterons

which allows for “clean” neutron measurements

This design feature permits a high polarization for all light ion beams

(The electron ring has a similar shape since it shares a tunnel with the ion ring)

Use Siberian Snakes/solenoids to arrange polarization at IPs

IIP

IP

longitudinal axis

IIP

IP

Vertical axis

IP

IIP

Solenoid

IP

IIP

Insertion

Longitudinal polarization at both IPs

Transverse polarization at both IPs

Longitudinal polarization at one IP

Transverse polarization at one IP

Proton or Helium-3 beams Deuteron beam

Slide 25

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Design Features: High Luminosity

• Follow a proven concept: KEK-B @ 2x1034 /cm2/s– Based on high bunch repetition rate CW colliding beams– Uses crab crossing

• MEIC aims to replicate this concept in colliders w/ hadron beams• The CEBAF electron beam already possesses a high bunch repetition rate • Add ion beams from a new ion complex to match the CEBAF electron

beam

KEK-B MEIC

Repetition rate MHz 509 748.5

Particles per bunch (e-/e+) or (p/e-) 1010 3.3 / 1.4 0.42 / 2.5

Beam current A 1.2 / 1.8 0.5 / 3

Bunch length cm 0.6 1 / 0.75

Horizontal & vertical β* cm 56 / 0.56 10/2 to 4/0.8

Beam energy (e-/e+) or (p/e-) GeV 8 / 3.5 60 / 5

Luminosity per IP, 1034 cm-2s-1 2 0.56 ~ 1.4

• high bunch repetition rate

• small bunch charge

• short bunch length (sz )

• small b* ( b* ~ sz )

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MEIC Accelerator R&D: Electron Cooling

• Electron Cooling in Collider – proof of principle of concept & techniques Cooling simulations are in progress (collaboration with Tech-X established through an SBIR grant)

ERL circulator cooler (linear optics and ERL) design has been completed Fast RF kicker concept has been developed, plan to test with two kickers from SLAC Test of beam-beam kicker concept at FNAL/ASTA facility and collaboration are in planning Optics design of a cooler test facility based on JLab FEL ERL has been completed

Solenoid (15 m

)

SRF

injector

dumper

MEIC Electron cooler

Dechirper Rechirper

e-Cooler Test Facility @ FEL

A technology demonstration possible using JLab FEL facility

• eliminating a long return path could double the cooling rate

(in center of figure-8)

Required R&D: demonstrate ERL-based cooler concept by 2016 (at FEL/ERL conditions)

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Proposed Cooling Experiments at IMP

Replacing the existing thermionic gun in the cooler by a JLab photo-cathode gun (Poelker)

Highly invasive to a user facility

Proposed experiments• Bunched electron beam to cool a DC ion beam

(New phenomena: longitudinal bunch (Hutton))• Bunched electron beam to cool a bunched ion

beams

(need an RF cavity for bunching the ion beams)

DC cooler

Storage rings for Heavy ion coasting beam

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Further ongoing MEIC Accelerator R&D• Space Charge Dominated Ion Beam in the Pre-booster

Simulation study is in progress by Argonne-NIU collaborators

• Beam Synchronization A scheme has been developed; SRF cavity frequency tunability study is in progress

• Beam-Beam Interaction Phase 1 simulation study was completed

• Interaction Region, Chromaticity Compensation and Dynamic Aperture Detector integration with IR design has been completed, offering excellent acceptance Correction scheme has been developed, and incorporated into the IR design Tracking simulations show excellent momentum acceptance; dynamic aperture is increased Further optimization in progress (e.g., all magnet spaces/sizes defined for IR +/- 100 m)

• Beam Polarization Electron spin matching and tracking simulations are in progress, achieving acceptable

equilibrium polarization and lifetime (collaboration with DESY) New ion polarization scheme and spin rotators have been developed (collaboration with

Russian group) – numerical demonstration of figure-8 concept with misalignments ongoing

• Electron Cloud in Ion Ring

• Ion Sources (Polarized and Universal)

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solenoid

electron FFQs50 mrad

0 mrad

ion dipole w/ detectors

ions

electrons

IP

ion FFQs

2+3 m 2 m 2 m

Detect particles with angles below 0.5o beyond ion FFQs and in arcs.Need 4 m machine element free region

detectors

Central detector Detect particles with

angles down to 0.5o before ion FFQs.Need 1-2 Tm dipole.

EM

Cal

orim

eter

Had

ron

Cal

orim

eter

Muo

n D

etec

tor

EM

Cal

orim

eter

Solenoid yoke + Muon Detector

TOF

HT

CC

RIC

H

RICH or DIRC/LTCC

Tracking

2m 3m 2m

4-5m

Solenoid yoke + Hadronic Calorimeter

Very-forward detectorLarge dipole bend @ 20 meter from IP (to correct the 50 mr ion horizontal crossing angle) allows for very-small angle detection (0.1-0.3o).Need 20 m machine element free region

MEIC: Full Acceptance Detector

7 meters

Three-stage detection

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MEIC Point Design Parameters

Detector type Full acceptance high luminosity & Large Acceptance

Proton Electron Proton Electron

Beam energy GeV 60 5 60 5

Collision frequency MHz 750 750 750 750

Particles per bunch 1010 0.416 2.5 0.416 2.5

Beam Current A 0.5 3 0.5 3

Polarization % > 70 ~ 80 > 70 ~ 80

Energy spread 10-4 ~ 3 7.1 ~ 3 7.1

RMS bunch length mm 10 7.5 10 7.5

Horizontal emittance, normalized µm rad 0.35 54 0.35 54

Vertical emittance, normalized µm rad 0.07 11 0.07 11

Horizontal and vertical β* cm 10 and 2 10 and 2 4 and 0.8 4 and 0.8

Vertical beam-beam tune shift 0.014 0.03 0.014 0.03

Laslett tune shift 0.06 Very small 0.06 Very small

Distance from IP to 1st FF quad m 7 3.5 4.5 3.5

Luminosity per IP, 1033 cm-2s-1 5.6 14.2

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EIC Realization Imagined

Assumes endorsement for an EIC at the next NSAC Long Range PlanAssumes relevant accelerator R&D for down-select process done around 2016

Activity Name 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025

12 GeV Upgrade

FRIB

EIC Physics Case

NSAC LRP

EIC CD0

EIC Machine Design/R&D

EIC CD1/Downsel

EIC CD2/CD3

EIC Construction

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Summary

• There has been excellent progress on developing the EIC science case over the last 2 years, with important contributions from both the BNL and JLab communities. White paper now available.

• We anticipate an NSAC Long Range Plan in the next 2-3 years – need to realize a recommendation for EIC construction.

• MEIC design is stable and mature. R&D planning in progress, with good opportunities for collaboration.

• We are hopeful that an international collaboration can develop to advance the science and technology of electron ion colliders.

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Announcement

EIC14 An International Workshop for Accelerator science

and Technology for Electron-ion Collider

March 24 – 28, 2014

Newport News, Virginia, USA

Y. Zhang, IMP Seminar 34

Welcome to Virginia!