EIC Detectors Tanja Horn Tanja Horn, CUA Colloquium Tanja Horn, EIC Detectors, INT10-3 INT10-3 “Science Case for an EIC”, Institute for Nuclear Theory,

EIC Detectors

Tanja Horn

Tanja Horn, CUA ColloquiumTanja Horn, EIC Detectors, INT10-3

INT10-3 “Science Case for an EIC”, Institute for Nuclear Theory, UW, Seattle

16 November 2010

1

Science of an EIC: Explore and Understand Science of an EIC: Explore and Understand QCDQCD

Tanja Horn, EIC Detectors, INT10-3 2

• Map the spin and 3D quark-gluon structure of nucleons+ Image the 3D spatial distributions of gluons and sea quarks through exclusive J/Ψ, γ (DVCS) and

meson production

+ Measure ΔG, and the polarization of the sea quarks through SIDIS, g1, and open charm production

+ Establish the orbital motion of quarks and gluons through transverse momentum dependent observables in SIDIS and jet production

• Discover collective effects of gluons in nuclei+ Discover signatures of dynamics of strong color fields in nuclei at high energies in eA->e’X(or

A) and eA->e’hadronsX

+ Measure fundamental gluon/quark radii of nuclei through coherent scattering g* + A J/Y + A

+ Explore the nuclear modification of the nucleon's basic gluonic momentum and spatial structure through e + A e‘ + X and e + A e' + cc + X

• Understand the emergence of hadronic matter from quarks and gluons− Explore the interaction of color charges with matter (energy loss, flavor dependence, color

transparency) through hadronization in nuclei in e + A e' + hadrons + X

− Understand the conversion of quarks and gluons to hadrons through fragmentation of correlated quarks and gluons and breakup in e + p e' + hadron + hadron + X

C. Weiss

s

• For large or small y, uncertainties in the kinematic variables become large

Range in y Q2 ~ xys

Range in s

Range of kinematics

• Detecting only the electron ymax

/ ymin

~ 10

• Also detecting all hadrons ymax

/ ymin

~ 100

– Requires hermetic detector (no holes)

• Accelerator considerations limit smin

– Depends on smax

(dynamic range)

• At fixed s, changing the ratio Ee / E

ion can for

some reactions improve resolution, pid, and acceptance

– Luminosity may be lower than shown in profile

C. WeissC. Weiss

valence quarks/gluons

non-pert. sea quarks/gluons

radiative gluons/sea

[Weiss 09]

s

To cover the physics we need…To cover the physics we need…

3Tanja Horn, EIC Detectors, INT10-3

1. 1. To a large extent driven by exclusive physicsTo a large extent driven by exclusive physics

22. But not only .... But not only ...

• Hermeticity (also for hadronic reconstruction methods in DIS)• Particle identification (also SIDIS)• Momentum resolution (kinematic fitting to ensure exclusivity)• Forward detection of recoil baryons (also baryons from nuclei)• Muon detection (J/Ψ)• Photon detection (DVCS)

• Very forward detection (spectator tagging, diffractive, coherent nuclear, etc)

• Vertex resolution (charm)• Hadronic calorimetry (jet reconstruction)

Detector RequirementsDetector Requirements


Where do particles go - generalWhere do particles go - general

p or A eSeveral processes in e-p:

1)“DIS” (electron-quark scattering) e + p e’ + X

2)“Semi-Inclusive DIS (SIDIS)” e + p e’ + meson + X

3)“Deep Exclusive Scattering (DES)” e + p e’ + photon/meson + baryon

4)Diffractive Scattering e + p e’ + p + X

5)Target fragmentation e + p e’ + many mesons + baryons

Token example:

1H(e,e’π+)n


In general, e-p and even more e-A colliders have a large fraction of their science related to the detection of what happens to the ion beams. The struck quark remnants can be guided to go to the central detector region with Q2 cuts, but the spectator quark or struck nucleus remnants will go in the forward (ion) direction.

[Ent 10]

Even more processes in e-A:

1) “DIS” e + A e’ + X

2) “SIDIS” e + A e’ + meson + X

3) “Coherent DES” e + A e’ + photon/meson + nucleus

4) Diffractive Scattering e + A e’ + A + X

5) Target fragmentation e + A e’ + many mesons + baryons

6) Evaporation processes e + A e’ + A’ + neutrons

10 on 60

• Modest (up to ~6 GeV) electron energies in central & forward-ion direction.

• Electrons create showers electron detectors are typically compact.

Scattered Electron Kinematics


low-Q2 electrons in electron endcap

high-Q2 electrons in central barrel: 1-2 < p < 4 GeV

Mo

me

ntu

m (

Ge

V/c

)

Mo

me

ntu

m (

Ge

V/c

)

Electron Scattering Angle (deg) Electron Scattering Angle (deg)

[Horn 08+]

•Larger energies (up to Ee) in the forward-electron direction: low-Q2 events.

7

4 on 250 GeV4 on 50 GeV

diff

ract

ive

DIS

• Both processes produce high-momentum mesons at small angles

• Small angle detection important for understanding target fragmentation

Diffractive and SIDIS (TMDs)[W. Foreman 09]

Tanja Horn, EIC Detectors, INT10-3

10°

5°


Horn 08+recoil baryonsscattered electronsmesons

4 on

250

GeV

4 on

30

GeV

t/t ~ t/Ep

Θ~√t/Ep

PID challenging

very high momenta

electrons in central barrel, but p different

0.2° - 0.45°

0.2° - 2.5°

ep → e'π+n

Exclusive light meson kinematics

Nuclear Science: Map t between tmin and 1 (2?) GeV Must cover between 1 and 5 degrees Should cover between 0.5 and 5 degrees Like to cover between 0.2 and 7 degrees

= 5 = 1.3

Ep = 12 GeV Ep = 30 GeV Ep = 60 GeV

t ~ Ep22 Angle recoil baryons = t½/Ep

t resolution ~ ~ 1 mr


Where do particles go - baryons

[Horn 08+]

DES at higher electron energies4 on 30 5 on 50 10 on 50

Mo

me

ntu

m (

Ge

V/c

)

Lab Scattering angle (deg) Lab Scattering angle (deg) Lab Scattering angle (deg)

10Tanja Horn, EIC Detectors, INT10-3[Horn 08+]

• Need particle ID for p>4 GeV/c in central region

• A DIRC is not sufficient for π/K separation already at relatively modest energies

• Two options

+ Supplement the DIRC with a C4F8O gas Cherenkov (threshold or RICH)

+ Replace it with a dual radiator (aerogel/gas) RICH

• Most important for exclusive reactions, but also for SIDIS, etc.

11

IP

ultra forwardhadron detection

dipole

dipole

low-Q2

electron detectionlarge apertureelectron quads

small diameterelectron quads

ion quads

small anglehadron detection

dipole

central detector with endcaps

EM

Cal

orim

eter

Had

ron

Cal

orim

eter

Muo

n D

etec

tor

EM

Cal

orim

eter

Solenoid yoke + Hadronic Calorimeter

Solenoid yoke + Muon Detector

HT

CC

RIC

H

Cerenkov

Tracking

5 m solenoid

3° beam (crab) crossing angle

TOF (+ DIRC ?)

• Apertures for small-angle ion and electron detection not shown


MEIC interaction region and central detector layout

solenoid

electron FFQs50 mrad

0 mrad

ion dipole w/ detectors

(approximately to scale)

ions

electrons

IP

ion FFQs

2+3 m 2 m 2 m

(“full-acceptance” detector)

Three-stage strategy using 50 mrad crossing angle

Detect particles with angles below 0.5° using 20 Tm dipole beyond ion FFQs.

Distance IP – ion FFQs = 7 m(Driven by push to 0.5 degrees detection before ion FFQs)

detectors

Central detector, more detection space in ion direction as particles have higher momenta.

Detect particles with angles down to 0.5° (10 mrad) before ion FFQs.

Need 2 Tm dipole (for 100 GeV proton beams) in addition to central solenoid.


Forward Ion Detection

Detector Endcaps

13Tanja Horn, Introduction to EIC/detector

concept, Exclusive Reactions Workshop 2010

• Bore angle: ~45° (line-of-sight from IP)

• High-Threshold Cerenkov (e/π)

• Time-of-Flight Detectors? Hadrons, event reconstruction, trigger

• Electromagnetic Calorimeter (e/π)

• Bore angle: 30-40° (line-of-sight from IP)

• Ring-Imaging Cerenkov (RICH)

• Time-of-Flight Detectors (event recon., trigger)

• Electromagnetic Calorimeter? Pre-shower for γ/π° -> γγ

(very small opening angle at high p)

• Hadronic Calorimeter (jets)

• Muon detector (J/Ψ production at low Q2)

Space constraintsSpace constraints

Electron side (left)Electron side (left)

Ion side (right)Ion side (right)

• Electron side has a lot of space

• Ion side limited by distance to FFQ quads (7 m)

EM

Cal

orim

eter

Had

ron

Cal

orim

eter

Muo

n D

etec

tor

EM

Cal

orim

eter

TOF

HT

CC

RIC

HTracking


Central Detector

14Tanja Horn, Introduction to EIC/detector concept, Exclusive Reactions Workshop

2010

• 3-4 T solenoid with about 4 m diameter

• Hadronic calorimeter and muon detector integrated with the return yoke (c.f. CMS)

• TOF for low momenta

• π/K separation options

– DIRC up to 4 GeV

– DIRC + LTCC (or dual radiator RICH): up to 9 GeV

• p/K separation

+ DIRC up to 7 GeV

• e/π separation

– C4F

8O LTCC up to 3 GeV

Solenoid Yoke, Hadron Calorimeter, MuonsSolenoid Yoke, Hadron Calorimeter, Muons

Particle IdentificationParticle Identification

• Low-mass vertex tracker

• GEM-based central tracker

• Conical endcap trackers



LTCC / RICH

Tracking

TrackingTracking


Δp/p ~ σp / BR2175°

R1

R2

Crossing angle

• A 2 Tm dipole covering 3-5° eliminates divergence at small angles

• Only solenoid field B (not R) matters at very forward rapidities

• A 3° beam crossing angle moves the region of poor resolution away from the ion beam center line.

– 2D problem!

• Tracker (not magnet!) radius R is important at central rapidities

– Conical trackers improve resolution at endcap corners by (R

2/R

1)2 ~ 4 (not shown)

• position resolution σ~ 100 microns

– CLAS DCs designed for 150 microns

particle momentum = 5 GeV/c 4 T ideal solenoid field

cylindrical tracker with 1.25 m radius (R1)

Goal: dp/p ~ 1% @ 10 GeV/cGoal: dp/p ~ 1% @ 10 GeV/c


Resolution dp/p in solenoid

-10000

-8000

-6000

-4000

-2000

0

2000

4000

6000

8000

10000

-20000 -15000 -10000 -5000 0 5000 10000 15000 20000x [cm]

z [cm]

Figure-8 Collider Ring - Footprint

Present thinking: ion beam has 50 mr horizontal crossing angle

Renders good advantages for very-forward particle detection

20 Tm dipole @ ~20 m from IP

(Reminder: MEIC/ELIC scheme uses 50 mr crab crossing)


Use Crab Crossing for Very-Forward Detection

[Zhang09+]

ionsions

17

326269

Thu Jul 15 22:13:10 2010 OptiM - MAIN: - C:\Working\ELIC\MEIC\Optics\Disp_Figure8_rel\Ring_13_period_1.opt

65

00

1-1

BE

TA

_X

&Y

[m]

DIS

P_

X&

Y[m

]

BETA_X BETA_Y DISP_X DISP_Y73.59280

Thu Jul 15 22:14:56 2010 OptiM - MAIN: - C:\Working\ELIC\MEIC\Optics\5GeV Electe. Ring\Spin_rotator_match_7_IR.

65

00

1-1

BE

TA

_X

&Y

[m]

DIS

P_

X&

Y[m

]

BETA_X BETA_Y DISP_X DISP_Y

348.93239

Thu Jul 15 22:52:10 2010 OptiM - MAIN: - C:\Working\ELIC\MEIC\Optics\Ion Ring_900\Arc_Straight_IR_Str_90_in_2.o

26

00

0

5-5

BE

TA

_X

&Y

[m]

DIS

P_

X&

Y[m

]

BETA_X BETA_Y DISP_X DISP_Y

IP

electrons

ions

8 m drift space after low-Q2 tagger dipole

Chromaticity Compensation

Block

IR

Spin Rotator

Arc end

Chromaticity Compensation BlockArc end

Very forward ion tagging

20 Tm analyzing

dipole


MEIC Interaction Region – forward tagging[Bogacz 10]


Detector/IR – Forward & Very Forward

• Ion Final Focusing Quads (FFQs) at 7 meter, allowing ion detection down to 0.5o before the FFQs (BSC area only 0.2o)

• Use large-aperture (10 cm radius) FFQs to detect particles between 0.3 and 0.5o (or so) in few meters after ion FFQ triplet

x-y @ 12 meters from IP = 2 mm

12 beam-stay-clear 2.5 cm

0.3o (0.5o) after 12 meter is 6 (10) cm

• Large dipole bend @ 20 meter from IP (to correct the 50 mr ion horizontal crossing angle) allows for very-small angle detection (< 0.3o)

x-y @ 20 meters from IP = 0.2 mm

10 beam-stay-clear 2 mm

2 mm at 20 meter is only 0.1 mr…

(bend) of 29.9 and 30 GeV spectators is 0.7 mr = 2.7 mm @ 4 m

Situation for zero-angle neutron detection very similar as at RHIC!

enough space for Roman Pots & small-angle calorimeters

[Slide from R. Ent 10]

• From arc where electrons exit and magnets on straight section

Synchrotron radiation Synchrotron radiation

Random hadronic backgroundRandom hadronic background

• Dominated by interaction of beam ions with residual gas in beam pipe between arc and IP

• Comparison of MEIC (at s = 4,000) and HERA (at s = 100,000)Comparison of MEIC (at s = 4,000) and HERA (at s = 100,000)

− Distance from ion exit arc to detector: 50 m / 120 m = 0.4

− Average hadron multiplicity: (4000 / 100000)1/4 = 0.4

− p-p cross section (fixed target): σ(90 GeV) / σ(920 GeV) = 0.7

− At the same ion current and vacuum, MEIC background should be about 10% of HERAo Can run higher ion currents (0.1 A at HERA)o Good vacuum is easier to maintain in a shorter section of the ring

• Backgrounds do not seem to be a major problem for the MEICBackgrounds do not seem to be a major problem for the MEIC

− Placing high-luminosity detectors closer to ion exit arc helps with both background types

− Signal-to-background will be considerably better at the MEIC than HERAo MEIC luminosity is more than 100 times higher (depending on kinematics)

Backgrounds and detector placementBackgrounds and detector placement


20

EM

Cal

orim

eter

Had

ron

Cal

orim

eter

Muo

n D

etec

tor

EM

Cal

orim

eter



HT

CC

RIC

H

Cerenkov

Tracking

5 m solenoid

• JLab layout has conical rather than cylindrical forward / backward trackers (with line-of-sight from IP)

• JLab detector does not have the forward RICH inside the solenoid magnet

• JLab detector reserves space for DIRC readout (but details need to be worked out!)

• JLab detector allocates space for Cerenkov (LTCC) in central barrel for high-momentum PID

• JLab interaction region has a larger ion beam crossing angle 50-60 mrad vs 10 mrad

Minor differencesMinor differences


JLab and BNL central detector layouts similar

JLab BNL[Nadel-Turonski talk week 5] [Aschenauer talk week 1&8]

eRHIC Detector ConcepteRHIC Detector Concept


Forward / BackwardForward / Backward

Spectrometers:Spectrometers:

2m2m 4m4m

central detector acceptance: very high coverage -5 < central detector acceptance: very high coverage -5 < < 5 < 5

Tracker and ECal coverage the sameTracker and ECal coverage the same

crossing angle: 10 mrad; crossing angle: 10 mrad; y = 2cm and y = 2cm and x = 2/4cm (electron/proton direction) x = 2/4cm (electron/proton direction)

Dipoles needed to have good forward momentum resolution and acceptanceDipoles needed to have good forward momentum resolution and acceptance

DIRC, RICH hadron identification DIRC, RICH hadron identification , K, p, K, p

low radiation length extremely critical low radiation length extremely critical low lepton energies low lepton energies

precise vertex reconstruction (< 10 precise vertex reconstruction (< 10 m) m) separate Beauty and Charmed Meson separate Beauty and Charmed Meson

minimum angle for “elastic protons”

minimum angle for “elastic protons”

to be detected in the main detector

to be detected in the main detector

10 mrad 10 mrad p p tt = 1 GeV

= 1 GeV

[Aschenauer talk week 1&8]

IR-Design-Version-IIR-Design-Version-I

0.44

m0.

44 m

Q5Q5D5D5

Q4Q4

90 m90 m

10 mrad10 mrad 0.

329

m0.

329

m

3.67 mrad3.67 mrad

60 m60 m

1010 2020 3030

0.18

8036

m0.

1880

36 m

18.8 m

18.8

m

16.8 m

16.8 m

6.33 mrad

6.33 mrad4 m4 m

DipoleDipole

© D.Trbojevic© D.Trbojevic

30 GeV e30 GeV e--

325 GeV p325 GeV p

125 GeV/u ions

125 GeV/u ions

eRHIC - Geometry high-lumi IR with β*=5 cm, l*=4.5 meRHIC - Geometry high-lumi IR with β*=5 cm, l*=4.5 mand 10 mrad crossing angleand 10 mrad crossing angle

Assume 50% operations efficiencyAssume 50% operations efficiency

4fb4fb-1 -1 / week / week


SpinSpin

rotatorrotator

[Aschenauer talk week 1]

22 44 66 88 1010

2.5 m2.5 m

3.5 m3.5 m

1212 1414

90 mm90 mm

5.75 m5.75 m

1616

IPIP

Dipole:Dipole:

2.5 m, 6 T2.5 m, 6 T

=18 mrad=18 mrad

4.5 m4.5 m=18 mrad=18 mrad

=10 mrad=10 mrad

Estimated Estimated **≈ 8 cm≈ 8 cm

=44 mrad

=44 mrad

6.3 cm6.3 cm ZDCZDC

pp cc/2.5/2.5

15.7 cm15.7 cm

6 mrad6 mrad

11.2 cm11.2 cm

4.5 cm4.5 cmneutronsneutronsppcc/2.5/2.5

IP configuration for eRHIC – IP configuration for eRHIC – Version-IIVersion-II


ee

Quad Gradient: Quad Gradient:

200 T/m200 T/m


0.44

843

m0.

4484

3 m

Q5Q5 D5D5Q4Q4

90.08703 m90.08703 m

10 mrad10 mrad0.

3906

5 m

0.39

065

m

60.0559 m60.0559 m

1010 2020 3030

0.33

3 m

0.33

3 m

IP configuration for eRHIC – IP configuration for eRHIC – Version-IIVersion-II


4 m4 m

4.54.5

=18 mrad

=18 mrad

5.75 m5.75 m

5.75 cm5.75 cm

11.9

m11

.9 m

17.65 m17.65 m

=27.194 mrad

=27.194 mrad


Summary

Tanja Horn, EIC@JLab - taking nucleon structure beyond the valence region, INT09-43W 25Tanja Horn, EIC Detectors, INT10-3

• JLab and BNL detector concepts generally similar

• Emphasis on small-angle coverage+ Three stage approach for forward hadron detection

• Detector is well suited for a wide range of experiments

• Integration with accelerator important

• Goal: hermetic detector with high resolution over full acceptance

Backup material

Tanja Horn, EIC@JLab - taking nucleon structure beyond the valence region, INT09-43W 26Tanja Horn, EIC Detectors, INT10-3

4 on 60

• Modest (up to ~6 GeV) electron energies in central & forward-ion direction.

• Electrons create showers electron detectors are typically compact.

• Larger energies (up to Ee) in the forward-electron direction: low-Q2 events.

• Requirements on the electron side are dominated by near-photon physics: electrons need to be peeled away from beam by tagger magnet(s).

Mo

me

ntu

m (

Ge

V/c

)

Mo

me

ntu

m (

Ge

V/c

)

Scattered Electron Kinematics


low-Q2 electrons in electron endcap

high-Q2 electrons in central barrel: 1-2 < p < 4 GeV

Kinematic CoverageKinematic Coverage


x ~ Q2/ys

mEIC at JLab, 11 on 60 GeVJLab 12 GeVH1ZEUS

HERA, y=0.004 mEIC 3 on 20, y=0.004

x

Q2

(GeV

2 )

[Nadel-Turonski 09]

28

xQ

2 (G

eV2 )

High Density Matter

Nuclear Structure & Low x Parton Dynamics

High precision partons in LHC plateau Large x

partons

New physics on scales ~10-19

LHeC Experiment

• Overlaps with HERA and the LHeC

• Overlaps (or close to overlap) with JLab 12 GeV

• Gives an order of magnitude higher reach in s than COMPASS and a much higher luminosity

s (CM energy)

A medium-energy EIC is complementary to the LHeC

Detector/IR in pocket formulas

•max ~ 2 km = l2/* (l = distance IP to 1st quad)

• IP divergence angle ~ 1/sqrt(*)

• Luminosity ~ 1/*

Example: l = 7 m, * = 20 mm max = 2.5 km

Example: l = 7 m, * = 20 mm angle ~ 0.3 mr

Example: 12 beam-stay-clear area

12 x 0.3 mr = 3.6 mr ~ 0.2o

Making * too small complicates small-angle (~0.5o) detection before ion Final Focusing Quads, and would require too

high a peak field for these quads given the large apertures (up to ~0.5o). * = 1-2 cm and Ep = 20-60+ GeV ballpark right!

• FFQ gradient ~ Ep,max /sqrt(*) (for fixed max, magnet length)

Example: 6.8 kG/cm for Q3 @ 12 m @ 60 GeV

7 T field for 10 cm (~0.5o) aperture


Documents

EIC Detectors Tanja Horn Tanja Horn, CUA Colloquium Tanja Horn, EIC Detectors, INT10-3 INT10-3 “Science Case for an EIC”, Institute for Nuclear Theory,