EIC Users Meeting 6/25/2014 The MEIC Design at Jefferson Laboratory Fulvia Pilat for the MEIC Study Group EIC Users Meeting Stony Brook, June 24-27, 2014

EIC Users Meeting 6/25/2014

The MEIC Design atJefferson Laboratory

Fulvia Pilat for the MEIC Study Group

EIC Users Meeting

Stony Brook, June 24-27, 2014


Context and updates

The MEIC strategy and base of design have not significantly changed in 3+yearsThe “Science Requirements and Conceptual Design for a polarized MEIC at JLAB” published in 2012Augmented the JLAB EIC study Group with additional external collaborationsResolved many of the design challenges, working on resolving remaining onesWorking to support the NSAC process

MEIC design strategy towards high luminosity and polarization (the full scope of EIC is consistent with an upgrade of the MEIC)

High level status of the design, R&D and remaining challenges

Vision and steps towards a Conceptual Design Report (CDR)

Conclusions and outlook

Outline

2


arXiv:1209.0757

Table of ContentsExecutive Summary

1. Introduction

2. Nuclear Physics with MEIC

3. Baseline Design and Luminosity Concept

4. Electron Complex

5. Ion Complex

6. Electron Cooling

7. Interaction Regions

8. Outlook

MEIC Design Report Released

3


MEIC Study Group

4


MEIC Design Goals

EnergyFull coverage of √s from 15 to 70 GeVElectrons 3-12 GeV, protons 20-100 GeV, ions 12-40 GeV/u

Ion speciesPolarized light ions: p, d, 3He, and possibly LiUn-polarized light to heavy ions up to A above 200 (Au, Pb)

At least 2 detectors Full acceptance is critical for the primary detector

LuminosityAbove 1033 cm-2s-1 per IP in a broad CM energy rangeMaximum luminosity >1034 optimized to be around √s=45 GeV

PolarizationAt IP: longitudinal for both beams, transverse for ions onlyAll polarizations >70%

Upgrade to higher energies and luminosity possible20 GeV electron, 250 GeV proton, and 100 GeV/u ion

Design goals consistent with the White Paper requirements

5


MEIC Layout

Warm large booster(3 to 25 GeV/c)

Warm electron collider ring (3-12 GeV) Medium-energy IPs with

horizontal beam crossing

Injector

12 GeV CEBAF

Pre-booster

SRF linac

Ionsource

Cold ion collider ring (25 -100 GeV)

Three Figure-8 rings stacked vertically

IP IP

Ion Sourc

e

Pre-booster

Linac

12 GeV CEBAF

12 GeV

11 GeV

Full Energy EIC Collider rings

MEIC collider rings

Three compact rings:•3 to 12 GeV electron•Up to 25 GeV/c proton (warm)•Up to 100 GeV/c proton (cold)

6


CEBAF Commissioning

7



Design Strategy for: High Luminosity

The MEIC design concept for high luminosity is based on high bunch repetition rate CW colliding beams

Beam Design• High repetition rate• Low bunch charge • Short bunch length• Small emittance

IR Design• Small β*• Crab crossing

Damping• Synchrotron radiation

• Electron cooling

“Traditional” hadrons colliders Small number of bunches Small collision frequency f Large bunch charge n1 and n2

Long bunch length Large beta-star

yyx

nnf

nnfL

*21

**21 ~

4

KEK-B already reached above 2x1034 /cm2/s

Linac-Ring colliders•Large beam-beam parameter for the electron beam•Need to maintain high polarized electron current •High energy/current ERL

9


Design strategy for High Polarization

All rings have a figure-8 shape with critical advantages for both ion and electron beam Spin precessions in the left & right parts of the ring are exactly cancelled Net spin precession (spin tune) is zero, thus energy independent Spin is easily controlled and stabilized by small solenoids or other compact spin rotators

Advantage 1: Ion spin preservation during acceleration

Ensures spin preservation Avoids energy-dependent spin sensitivity for all species of ions Allows a high polarization for all light ion beams

Advantage 2: Ease of spin manipulation • Delivering desired polarization at multiple collision points

Advantage 3: The only practical way to accommodate polarized deuterons(ultra small g-2)

Advantage 4: Strong reduction of quantum depolarization thanks to the energy independent spin tune

This helps to preserve polarization of the electron beam continuously injected from CEBAF

10


• Ring-Ring with CEBAF as a full energy polarized injector

• Avoids a class of challenging technology R&D (i.e. high current polarized electron source, high energy high current ERL)

• 12 GeV CEBAF source/injector already meets the requirements

• Delivers high luminosity and high polarization

Key design choices

We took some conservative technical choices:

• Limit key design parameters (beam-beam and space charge parameters) within or close to the present state-of-art

• Maximum peak field: SC dipole < 6 T; warm dipole: <1.6 T

• Maximum synchrotron radiation power density at 20 kW/m

• Manageable final focusing: maximum beta at the final focus quads is 2.5 km

11


Detector Full Acceptance Large AcceptanceProton 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 cm 1 0.75 1 0.75

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 (down)3.5 (up)

3 4.5 (down)3.5 (up)

3

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

Nominal Design Parameters

12


MEIC/EIC e-A luminosity

13

EICMEIC


MEIC/EIC e- P Luminosity

A. Accardi

EICMEIC

14


MEIC systems

Ion injector Conventional technology, detailed simulations needed should not present an issue

Ion pre-booster Ion large booster Ion collider ring • Optimization of non-linear dynamics

correction started• Encouraging initial simulation results • New collaborations on Correction and DA

initiated

Electron collider ring Interaction regions

Polarization Preliminary spin tracking of figure 8 OK

Cooling Circulator design

Transfer lines, synchronization Recent work after EICAC

Overview of MEIC design and R&D

15

Critical MEIC R&D Status Talk

High current ERL and circulator Conceptual design, e-cooling simulations done

High charge/current magnetized e-source 2 options (thermionic gun or RF photo-cathode gun)

Ultra fast kicker RF harmonic kicker concept (JLAB LDRD)

Crab cavity New cavity design developed at ODU

E ring RF system R&D in progress at JLAB SRF


Ion Source Prototypes & Parameters

Electron-Cyclotron Resonance Ion Source (ECR)

Universal Atomic Beam Polarized Ion Sources (ABPIS)

Electron Beam Ion source (EBIS)

Polarized light Ions

Non-Polarized Ions

Ions Source Type

Pulse Width (µs)

Rep. Rate (Hz)

Pulsed current (mA)

Ions/pulse (1010)

Polarization (Pz)

Emittance (90%) (π·mm·mrad)

Note

H-/D- ABPIS 500 5 4 (10) 1000 >90% (95) 1.0 / 1.8 (1.2)

H-/D- ABPIS 500 5 150 / 60 40000/15000 0 1.8

3He++ ABPIS-RX 500 5 1 200 70% 1

3He++ EBIS 10 to 40 5 1 5 (1) 70% 1 BNL

6Li+++ ABPIS 500 5 0.1 20 70% 1

Pb30+ EBIS 10 5 1.3 (1.6) 0.3 (0.5) 0 1 BNL

Au32+ EBIS 10 to 40 5 1.4 (1.7) 0.27 (0.34) 0 1 BNL

Pb30+ ECR 500 5 0.5 0.5 (1) 0 1

Au32+ ECR 500 5 10.5 0.4 (0.6) 0 1

• Numbers in red are “realistic extrapolation for future”; numbers in blue are “performance requirements of BNL EBIS

• MEIC ion sources rely on existing and matured technologies• Design parameters are within the state-of-the-art

16


Ion Linac

Parameters Unit Value

Species p to lead

Reference Design 208Pb

Kinetic energy MeV/u 100

Max. pulse current Light ions (A/q≤3) Heavy ions (A/q≥3)

mAmA

2

0.5

Pulse repetition rate Hz 10

Pulse length ms 0.25

Max. beam pulsed power kW 680

Fundament frequency MHz 115

Total length M 150

SuperconductingNormal

conductingQWR

HWR

• Pulsed linac, peak power 680 kW

• Consists of quarter wave and half wave resonators

• Originally developed at ANL as a heavy-ion driver accelerator for Rare Isotope Beam Facility

• Adopted for MEIC ion linac because: • Satisfies MEIC ion linac requirements• Covers similar energies, variety of ion species• Excellent and mature design

• All subsystems are either commercially available or based on well-developed technologies

17


Ion Pre-boosterPurpose of pre-booster

• Accumulation of ions injected from linac• Acceleration of ions• Extraction and transfer of ions to the large

booster

Design ConceptsFigure-8 shape(Quasi-independent) modular design

• FODO arcs for simplicity and ease optics corrections

Design constraints• Maximum bending field: 1.5 T• Maximum quad field gradient: 20 T/m• Momentum compaction smaller than 1/25• Maximum beta functions less than 35 m• Maximum full beam size less than 2.5 cm, • 5m dispersion-free sections for RF, cooling,

collimation and extraction.

18

Inje

cti

on

Arc

1

Str

aig

ht

1

Arc

3

Str

aig

ht

2

Arc

2


200

0

200

200

0

200

5

0

5

MEIC Ion Large Booster• Accelerates protons from 3 to 25 GeV (and ion energies with similar magnetic rigidity)• Follow electron/ion collider ring footprints, housed in same tunnel• Made of warm magnets and warm RF

• No transition energy crossing (always below γt=25.03)

• Quadrupole based dispersion suppression.• Tunable to any working point.

• Vertical chicane to bring low energy ions to the plane of the electron ring

• Add electron cooling and SRF

• Share detector with MEIC

IP

Possible to convert the large booster to

a low energy collider ring

19


Lattice design of geometrically-matched collider rings completed

Detector requirements fully satisfied

Collider Ring and IR Layout

20

IPs

e-

ions

e-

ions

IP


Detector Region Design

21

Fully-integrated detector and interaction region satisfyingX Detector requirements: full acceptance and

high resolutionX Beam dynamics requirements: consistent

with non-linear dynamics requirementsX Geometric constraints:

matched collider ring footprints

far forwardfar forwardhadron detectionhadron detectionlow-Q2

electron detectionelectron detection large-apertureelectron quads

small-diameterelectron quads

central detectorcentral detector with endcaps

ion quads

50 mrad beam(crab) crossing angle

n,

ep

p

small anglesmall anglehadron detectionhadron detection

~60 mrad bend

(from GEANT4)

2 Tm 2 Tm dipoledipole

EndcapEndcap Ion quadrupolesIon quadrupoles

Electron quadrupolesElectron quadrupoles

1 m1 m11 m m

IP FP

Roman potsRoman potsThin exit Thin exit windowswindows

Fixed Fixed trackers in trackers in vacuum?vacuum?

Trackers and “donut” calorimeterTrackers and “donut” calorimeter

RICH+

TORCH?

dual-solenoid in common cryostat4 m coil

barrel DIRC + TOF

EM

ca

lori

met

er

EM calorimeter

Tracking

EM

ca

lori

met

er

e/π

th

res

ho

ldC

he

ren

ko

v


MEIC Ion Collider Ring

R = 90.4 m

Arc, 2400

IPs

Long straight

Dog Leg #1

Dog Leg #2

Dog Leg #1

Dog Leg #2Detector elements

CCB/dispersion suppressorArc CCB

Arc CCB

Arc CCB

Arc CCB

FODO-cell arcs

CCB in arcs for local chromaticity correction

Vertical doglegs to bring ions to electron plane

X With horizontal bendX Dispersion suppression

22

Circumference m 1415.3

arc radius / length m 90.4 / 414.90

Long straight m 292.77

Max x/y functions m 2301 / 2450

Betatron tunes (x, y) 25(.79) / 26(.27)

Chromatisities x,y (2 IR) -224 / -233

Momentum compaction 10-3 5.76

Transition gamma tr 13.2

Norm. emittancesx,y m 0.35 / 0.07


MEIC Electron Collider RingFlat ring, defines geometry

FODO-cell arcs

All-energy Universal Spin Rotators (USR)

CCB in straights for chromaticity correction

23

Circumference m 1415.9

arc radius / length m 90.4 / 445.34

Long straight m 262.61

Max x/y functions m 769 / 842

Betatron tunes (x, y) 56(.65) / 52(.89)

Chromatisities x,y (2 IR) -204 / -203

Momentum compaction 10-3 0.76

Transition gamma tr 36.2

Norm. emittancesx,y m 53.5 / 10.7

R = 90.4 m

Arc 445m, 2400

USR, 13.2 , 54m

IPs

USR, 13.2 , 54m

USR, 13.2 , 54m USR, 13.2 , 54m

CCB

Forward e- detection

CCB Long straight


Change the harmonic number of the ion beam at discrete energies (harmonic jump)Employ two 10 cm path length chicanes (one per arc) between jumps

10 regular 3 m long arc dipoles per chicaneThe green dipoles are regular arc dipoles with fixed bending anglesThe bending of the outer and inner red dipoles is adjusted to change the path length

FeaturesX Provides coverage of the full energy rangeX Automatic synchronization of both IP’s with two chicanes for even number of ion bunchesX Requires total additional space of < 20 m (green dipoles are already a part of the arc)X No closed orbit shift (shift the design orbit instead), no SRF frequency change,

no CEBAF synchronization issue (electron frequency is fixed), no R&D requiredX Need to evaluate the engineering challenge of moving cold magnets by up to 50 cm

Beam Synchronization

24

x = 42.6 cm

x = -53.8 cm

Total bending angle and z length are fixed


Design requirements– High polarization (~80%) of protons and light ions (d, 3He++, and possibly 6Li+++)– Both longitudinal and transverse polarization orientations available at all IP’s– Spin flipping (through the source)

Figure-8 structure as a solution– No preferred periodic spin direction, energy-independent zero spin tune Polarization can be controlled by small magnetic fields– Eliminates depolarization problem during acceleration– Works for all ion species including deuterons

Acceleration and spin matching– Polarization is stabilized by weak (< 3 Tm) solenoids– Injection and extraction from straight with solenoid

Polarization control in the collider ring– Beam is injected longitudinally polarized, accelerated and

then the desired spin orientation is adjusted– Weak solenoids for deuterons (< 1.5 Tm each)– Weak radial-field dipoles for protons (< 0.25 Tm each)– Small or no orbit excursions, easy magnet field ramp

Ion Polarization

25


Design requirements– High polarization (>80%) and sufficient life time– Longitudinal polarization at all interaction points– Spin flipping (through the source) at required

frequencies

Highly vertically polarized electron beam is injected from CEBAF

Polarization is vertical in the arc to avoid spin diffusion

Universal spin rotator rotates polarization from vertical

to longitudinal at IP

Spin flipping through the source

Compton polarimeters to measure polarization

Continuous injection is considered to maintain high polarization at higher energies

Figure 8 structure removes electron spin tune energy dependence

Electron Polarization

26

arc

dipolearc dipole

Solenoid 1

Solenoid 2

α2≈4.4º α1≈8.8º

spin

φ1

e-

φ2spin

Lost or Extracted

P0 (>Pt)

Pt


Multi-Staged e-Cooling Scheme

ion sources

SRF Linac

pre-booster (3 GeV)(accumulation)

large booster (25 GeV)

medium energy collider ring

High Energy cooling

DC cooling

Stage Ion (GeV/u) Electron (MeV)

Cooling beam /Cooler

Pre-booster

Assisting accumulation of positive ions

0.1 (injection) long bunches

0.59 DC

Initial cooling to reduce emittance

3 (extraction)long bunches

2.1 DC

Collider ring

Initial cooling for emittance reduction

25 (injection) long bunches

13Bunched

/ERL

Final cooling for emittance reduction

Up to 100 bunched beam

55Bunched

/ERL

During collision (suppress IBS)

Up to 100 bunched beam, 1 cm

55Bunched

/ERL

state-of-the-art

27


Cooling Technology Staging

The “ready-to-build” version utilizes only (loosely speaking) existing and established accelerator technologies

Proton/ion Energy (GeV/u)

Ready-to-Build

Ultimate

Pre-booster DC electron cooling to assist accumulation of positive ions

0.1

DC electron cooling for emittance reduction

3

Collider ring ERL-based electron cooling at injection energy for emittance reduction

25 (option)

ERL-based electron cooling at top energy for emittance reduction

Up to 100 “Weak”

ERL-based electron cooling during collision to suppress IBS

Up to 100 “Weak”

Stochastic cooling of heavy ions during collision to suppress IBS

Up to 100

Luminosity 1033 1/cm2/s 1 ~ 3 5.6 ~ 14

28


Luminosity at different cooling stagesL

um

ino

sity

(10

33 1

/cm

2/s

)

Add “weak” electron cooling & stochastic cooling (heavy ions) during collision

Add 3 GeV DC cooling at pre-booster

Low energy DC cooling only at pre-

booster injection

Full capacity electron cooling (ERL-circulator cooler)

~0.41 ~1.1

~3.3

5.6

Based on existing technologies

EICAC recommendation

29


Jefferson Lab plans to have a comprehensive Conceptual Design Report in 2-3 years

Resources: Manpower:

Given competing priorities MEIC design and R&D have operated at the 5-6 FTE level at JLAB plus leveraged collaborations

The end of 12 GeV Project accelerator scope (12 GeV experiment till 2017 and the integration of FEL personnel in Accelerator and Engineering significantly increased manpower in 2014

Pursuing new collaborations

MEIC Design and R&D funding:

NP grants (mainly towards supporting 3 post-docs)

Commonwealth of Virginia funding

LDRD (fast kicker R&D)

SBIR (Tech-X)

JLAB Accelerator R&D funds

Plans towards CDR

30


A preliminary (“not ready for review” ) cost estimate for MEIC was carried out in 2012

A task force to issue a cost estimate for MEIC has been appointed at JLAB in January 2014 and is working now. The task force includes senior management from the 12 GeV Project, the Accelerator and Engineering Divisions, with support from the Project Management Group.

A comprehensive MEIC WBS to level 5

Baseline (Base of estimate) – June 2014

Engineering study - July 2014

Cost estimate – September-October 2014

Plan for cost estimate

31


Towards a Conceptual Design Report

Detector R&D

Report on High Energy Electron Cooling

Report on Beam Polarization DesignA

ccel

erat

or R

&D

Report on Detector /IR Design Studies

Existing Design Report

Design Optimization

MEIC Conceptual

Design Report

2MeV DC Cooler Technical Design Report

32


Accelerator Team & Current Collaboration

Core team (CASA): A. Bogacz, Y. Derbenev, D. Douglas, R. Li, R. Kazimi, G. Krafft, F. Lin, V. Morozov, Y. Roblin, M.Spata, C. Tennant, M. Tiefenback,

H. Zhang, Y. Zhang, students (C-Y Tsai , A. Castilla)

RF systems: F. Hannon, R. Rimmer, H. Wang, S. Wang (SRF R&D, Jlab)

RF Fast Kicker: A. Kimber (Engineering), C. Tennant LDRD

High current un-polarized e-source: R. Suleiman (Source, Jlab)

Interaction regions: M. Sullivan (SLAC)

Polarization: A. Kondratenko (Novosibirsk), D. Barber (DESY)

Low energy ion complex: linac: P. Ostroumov (Argonne Lab) pre-booster: B. Erdelyi (Northern Illinois Univ.)

Beam-beam simulation: J. Qiang (LBL)

Cooling Simulation: I. Pogorelov (Tech-X) SBIR

Nonlinear corrections, DA: D. Trbojevic, Y. Jing, Y. Luo (BNL) U. Wienands, Y. Nosochkov (SLAC)

33


Tasks assignments for Accelerator R&D towards CDR

ResponsibilityCore MEIC team High energy electron cooling

ERL-Circulator cooler developmentCollider rings and boosters designInteraction region designElectron polarizationInstabilities and collective effectsFast beam kicker

JLab internal collaboration Electron ring RF (SRF/Rimmer)Cooler demo (FEL/Douglas)

External collaboration (out-sourcing)

2D DC electron cooler technical designStochastic coolingIon polarization Ion sourcesIon linac (update)Low energy ion beam formationDetector backgroundNonlinear corrections, DA

To be determined Magnetized electron photo-cathode gun

34


The MEIC design fulfills the requirements for high luminosity and polarization needed by the nuclear physics community

We have a mature strategy and design and a very significant progress has been achieved on technical challenges in the last 3 years

We need to:

Demonstrate the remaining open technical issues with studies, modeling and a strategic and collaborative R&D program

Strengthen further the Design Team at Jefferson Lab as well as widen the external collaboration

Secure R&D funding commensurate with the stated goals

We believe we can deliver a comprehensive Conceptual Design Review in 2-3 years

Conclusions and outlook

35


Backup Slides

36


electron beams with high polarization are injected from CEBAF– avoid spin decoherence, simplify spin transport from CEBAF to MEIC, alleviate the detector background

Polarization is designed to be vertical in the arc to avoid spin diffusion and longitudinal at collision points using spin rotators

A Universal spin rotator rotates the electron polarization from 3 to 12GeV

spin flipping is implemented by changing the source polarization

A Compton polarimeter is considered for polarization measurements Two long opposite polarized bunch trains (instead of alternate polarization between bunches) simplify the Compton polarimetry

The figure-8 geometry removes electron spin dependence on energy

Continuous injection of electron bunch trains from the CEBAF is envisioned to preserve and/or replenish the electron polarization, especially at higher energies, and

maintain a constant beam current in the collider ring

Spin matching in some key regions is considered if it is necessary

Electron polarization

37

… …… …

Empty buckets Empty buckets1.33ns

748.5MHz

Polarization (Up) Polarization (Down)

bunch train & polarization pattern in the collider ring


Why a magnetized electron cooler?

With the cathode immersed in a solenoid, the gun generates an almost parallel (laminar) beam state of a large size

– Larmor circles very small compared to the beam size

This state is then transported to the solenoid in the cooling section – Conserves the canonical emittances

The solenoid field is chosen to make the electron beam size match properly the ion beam size

Magnetization results in the following critical advantages

(compared to a non-magnetized gun):

Large reduction (by two orders of value) of (local and global) space charge

Improves the dynamics in CCR (tune shift, micro-bunching)

Strong suppression of CSR micro-bunching/ energy spread growth

Limits reduction of cooling rates due to high electron transverse velocity spread and short-wave misalignments

– Ion collides with “frozen” electrons

38


Continuous injection principle

Note that:– Continuous injection mainly considered at higher energies– A relatively low averaged beam current of tens-of-nA level – Constant beam current maintained

On possible injection bunch pattern

Continuous Injection Technique

39

Lost or Extracted

P0 (>Pt)

Pt

10 )1(

injdk

ringrevequ I

ITPP

……

1.33 ns, 748.5 MHz 2.4 pC

2.3μs, ~1700 bunches2.4 pC

1.33 ns, 748.5 MHz

2.3μs, ~1700 bunches

……

……

1 ms

Iave = 59 nA 140 ms


Detector Type Full Acceptance High Luminosity

Proton Electron Proton Electron


Collision frequency MHz 748.5 748.5 748.5 748.5



Polarization ~ 80% > 80% ~ 80% > 80%


Energy spread 10-4 ~ 3 7.1 ~ 3 7.1

Normalized emittance, x/y µm rad 0.4 / 0.04 54 / 5.4 0.4 / 0.04 54 / 5.4

Horizontal and vertical β* cm 10 / 2 10 / 2 8 / 0.8 5.5 / 0.55

Beam-beam tune shift, x/y 0.014 0.03 0.014 0.03

Laslett tune shift 0.03 < 0.001 0.03 < 0.001

Distance from IP to 1st FF quad m7 (downstream)3.5 (upstream)

34.5 (downstream)3.5 (upstream)

3

Luminosity per IP, 1033 cm-2s-1 8.3 21

MEIC Nominal Parameters at Design Point 100X5 GeV2

40EICAC Meeting 2/28/14



Proton Electron Proton Electron




Beam Current A 0.25 2.6 0.25 2.6

Polarization ~ 80% > 80% ~ 80% > 80%


Energy spread 10-4 ~ 3 7.1 ~ 3 7.1







3

Luminosity per IP, 1033 cm-2s-1 2.4 6.0

MEIC Nominal Parameters at Design Point 50X5 GeV2




Lead Electron Lead Electron



Ions/electrons per bunch 1010 0.005 2.5 0.005 2.5


Polarization -- > 80% -- > 80%


Energy spread 10-4 ~ 3 7.1 ~ 3 7.1







3

Luminosity per nucleon-IP, 1033 cm-2s-1 11.3 28

MEIC Nominal Parameters for Lead Ion at Design Point 40X5 GeV2


EIC Users Meeting 6/25/2014 43EICAC Meeting 2/28/14


Item FY16 FY17 FY18 FY19 FY201. Optimize Research through Increased Weeks of Operation 6 3 3 7 7

Power/Cryogens 2.4 1.6 1.5 2.2 2.3Staffing to support 4-Hall operation 3.0 4.1 3.7 4.7 4.1Experimental Capital Equipment 0.5 0.8 1.3 2.3 2.3

Sub Total 5.9 6.5 6.5 9.2 8.7

• Reduce Risk of Major Disruptions in Machine and Experimental Hall Operations Spare Compressor for CHL-2 1.0 Spare C100 Cryomodule 1.0 1.5 0.5 End Station Refrigerator Upgrade/Replacement 0.5 0.5 0.5 0.5 0.5

CHL 1&2 Cold Compressor Controls 1.0 0.5 Sub Total 2.5 3.0 1.5 0.5 0.5

• Advance MEIC Research and Development 3.1 3.8 3.0 2.0 2.0

Sub Total 3.1 3.8 3.0 2.0 2.0

• Sustainability 4.0 3.0 2.0

MIE – MOLLER Experiment 4.7 10.7 6.2 0.7 LQCD / SciDAC – estimated funding based on discussion w/HEP/ONP 1.0 1.4 1.2 1.2 1.2

Priorities for Optimizing Scientific Output FY16-20(M$)



Universal Spin Rotator

• Rotating spin from vertical to longitudinal• Consists of 2 solenoids & 2 (fixed angle) arc dipoles• Universal

energy independent

works for all energies (3 to 12 GeV)

orbit independent

does not affect orbital geometry

Compensation of solenoid x-y coupling

arc

dipolearc

dipole

Solenoid 1

Solenoid 2

α2≈4.4º α1≈8.8º

spin

φ1 Electron

beamφ2spin

17.90320

Tue Jul 13 23:59:50 2010 OptiM - MAIN: - C:\Working\ELIC\MEIC\Optics\5GeV Electe. Ring\sol_rot_2.opt

15

0

1-1

BE

TA_

X&

Y[m

]

DIS

P_

X&

Y[m

]

BETA_X BETA_Y DISP_X DISP_Y

solenoid 4.16 m

decoupling quad insert

solenoid 4.16 m

V. Livinenko & A. Zholents, 1980

E (GeV)

1 BL1 (Tm)

1 2 BL2 (Tm)

2

3 /2 15.7 /3 0 0 /6

6 0.62 12.3 2/3 1.91 38.2 /3

9 /6 15.7 2/3 62.8 /2

12 0.62 24.6 4/3 1.91 76.4 2/3



Proton/He-3 Polarization at IPs

IIP

IP

• Three Siberian snakes, both in horizontal-axis• Vertical polarization direction periodic• Spin tune: 1/2

IIP

IPVertical

longitudinal • Two Siberian snake, with their parameters set at specific values. Spin tune: 1/2

Three Siberian snakes, all longitudinal-axis

Third snake in straight is for spin tune

Spin tune: 1/2

Case 1: Longitudinal Proton Polarization at IP’s

Case 2: Transverse proton polarization at IP’s

Case 3: Longitudinal & transverse proton polarization on two straights

IIP

IP

longitudinal axis

Vertical axis

axis in special angle



Deuteron Polarizations at IPs

Stable spin orientation can be controlled by magnetic inserts providing small spin rotation around certain axis and shifting spin tune sufficiently away from 0

Polarization is stable as long as additional spin rotation exceeds perturbations of spin motion

Polarization direction controlled in one of two straights

Longitudinal polarization in a straight by inserting solenoid(s) in that straight

Case 1: Longitudinal Deuteron Polarization at IP’s

IP

IIP

Solenoid

IP

IIP

Insertion

Case 2: Transverse Deuteron Polarization at IP’s

• Magnetic insert(s) in straight(s) rotating spin by relatively small angle around vertical axis (A. Kondratenko)


Documents

EIC Users Meeting 6/25/2014 The MEIC Design at Jefferson Laboratory Fulvia Pilat for the MEIC Study Group EIC Users Meeting Stony Brook, June 24-27, 2014