E.C. AschenauerEIC INT Program, Seattle 2010 - Week 11

EIC INT Program, Seattle 2010 - Week 1 1

IR- and Detector DesignConsiderations

E.C. Aschenauer


The Physics we want to study

What is the role of gluons and gluon self-interactions in nucleons and nuclei? Observables in eA / ep:

diffractive events: rapidity gap events, elastic VM production, DVCSstructure functions F2

A, FLA, F2c

A, FLcA, F2

p, FLp,………

What is the internal landscape of the nucleons? What is the nature of the spin of the proton?

Observables in ep inclusive, semi-inclusive Asymmetries electroweak Asymmetries (g-Z interference, W+/-)

What is the three-dimensional spatial landscape of nucleons? Observables in ep/eA

semi-inclusive single spin asymmetries (TMDs) cross sections, SSA of exclusive VM, PS and DVCS (GPDs)

What governs the transition of quarks and gluons into pions and nucleons? Observables in ep / eA

semi-inclusive c.s., ReA, azimuthal distributions, jets

E.C. Aschenauer

Spin 2010, Juelich 3

eRHIC Scope

e-

e+

p

Unpolarized andpolarized leptons5-20 (30) GeV

Polarized light ions He3 215 GeV/u

Light ions (d,Si,Cu)Heavy ions (Au,U)50-130 GeV/u

Polarized protons50-325 GeV

Electron acceleratorto be build

RHICexisting

70% e- beam polarization goalpolarized positrons?

Center mass energy range: √s=30-200 GeV; L~100-1000xHera

longitudinal and transverse polarization for p/He3 possible

e-

E.C. Aschenauer

Kinematic Coverage


Kinematics of scat. electron

Proton Energy50 GeV 100 GeV 250 GeV

Ele

ctr

on

En

erg

y 4

GeV

1

0 G

eV

2

0 G

eV

E.C. Aschenauer

scattered lepton goes to smaller

angles for same Q2 as √s increases

For any hadron beam energyQ2>0.1GeV2

4GeV >5o

10GeV >2o

20GeV >1o


Kinematics of semi-inclusive hadrons

E.C. Aschenauer

4x100 4x2504x50

momentum (GeV)

no cuts:

cuts: Q2 > 0.1 GeV && y < 0.9 GeV

hadrons gomore and moreforward withincreasing

asymmetry inbeam energies


Kinematics of elastic diffraction

E.C. Aschenauer

4x2504x1004x50

no cuts:

cuts: Q2 > 0.1 GeV && y < 0.9 GeV

decay products of r & J/ψ go more and more

forward withincreasing

asymmetry inbeam energies


Diffractive Physics: p’ kinematics

E.C. Aschenauer

4 x 100

t=(p4-p2)2 = 2[(mpin.mp

out)-(EinEout - pz

inpzout)] 4 x 50

4 x 250

?

Diffraction:

p’

need “roman pots” to detect the protons

and a ZDC forneutrons

t=(p3–p1)2 = mρ2-Q2 - 2(Eγ*Eρ-px

γ*pxρ-py

γ*pyρ-

pzγ*pz

ρ)


Additional Remarks

General Remarks detector should have stable acceptance to enable efficient

running at different energies (5 GeV x 50 GeV to 30 GeVx325 GeV)

reduces systematic FL

tracker, ECal and m-ID coverage must be the same to have good momentum and pt resolution

Charm detection structure functions

detecting lepton form decay in addition to scattered via displaced vertex should be enough

charm in fragmentationneed to reconstruct D0 meson completely to measure its z

good PID also required for semi-inclusive physics

lepton has only very little correlation to z of D-meson

E.C. Aschenauer


Measure gA(x) impact parameter dependent

E.C. Aschenauer

What are the real requirements: Momentum resolution t resolution and range what breakup particles need to be detected to veto incoherent,

what is the angular range, what suppression factor? n ZDC g ECAL in front of ZDC p very difficult because of over focussing of quads

A. Caldwell, H. Kowalski Phys.Rev.C81:025203,2010


How to measure coherent diffraction in e+A ?

Beam angular divergence limits smallest outgoing Qmin for p/A that can be measured

Can measure the nucleus if it is separated from the beam in Si (Roman Pot) “beamline” detectors pTmin ~ pz

Atan-1θmin

For beam energies = 100 GeV/n and θmin = 0.1 mrad

Large momentum kicks, much larger than binding energy (~8 MeV)

Therefore, for large A, coherently diffractive nucleus cannot be separated from beamline without breaking up

E.C. Aschenauer

species (A)

pTmin (GeV/c)

d (2) 0.02Si (28) 0.22Cu (64) 0.51In (115) 0.92Au (197) 1.58U (238) 1.90


How to measure coherent diffraction in e+A ?

E.C. Aschenauer

Rely on rapidity gap method simulations look good high eff. high purity

possible with gap alone ~1% contamination ~80% efficiency

depends critical on detector hermeticity

improve further by veto on breakup of nuclei (DIS) Very critical

mandatory to detect nuclear fragments from breakup

Purity Efficiency

rapidity


eSTAR

ePH

EN

IX100m

|--------|

Cohere

nt

e-co

ole

r

22.5 GeV

17.5GeV

12.5 GeV

7.5 GeV

Com

mon

vacu

um

ch

am

ber

27.5 GeV

2.5 GeV

Beam-dump

Polarized e-gun eRHIC

detector25 GeV

20 GeV

15 GeV

10 GeV

Com

mon

vacu

um

ch

am

ber

30 GeV

5 GeV

0.1 GeV

RHIC: 325 GeV p or 130 GeV/u Au

eRHIC: staging all-in tunnel

Gap 5 mm total0.3 T for 30 GeV

SRF linac

Vertically separatedrecirculating passes.# of passes will be chosen to optimize eRHIC cost

energy of electron beam is increasing from 5 GeV to 30 GeV by building-up the linacs

From RHIC to eRHIC

E.C. Aschenauer

eRHIC IR1

p /A e

Energy (max), GeV 325/130 20

Number of bunches 166 74 nsec

Bunch intensity (u) , 1011 2.0 0.24

Bunch charge, nC 32 4

Beam current, mA 420 50

Normalized emittance, 1e-6 m, 95% for p / rms for e

1.2 25

Polarization, % 70 80

rms bunch length, cm 4.9 0.2

β*, cm 5 5

Luminosity, cm-2s-1

1.46 x 1034

Luminosity for 30 GeV e-beam operation will be at 20% level


Emerging Detector Concept

E.C. Aschenauer

Forward / BackwardSpectrometers:

2m 4m central detector acceptance: very high coverage -5 < h < 5

Tracker and ECal coverage the same crossing angle: 10 mrad; Dy = 2cm and Dx = 2/4cm (electron/proton direction)

Dipoles needed to have good forward momentum resolution and acceptance DIRC, RICH hadron identification p, K, p low radiation length extremely critical low lepton energies precise vertex reconstruction (< 10 mm) separate Beauty and Charmed Meson


First Model of eRHIC Detector

E.C. Aschenauer

DIRC: not shown because of cut; modeled following Babar no hadronic calorimeter and m-ID jet

CALIC technology combines mID with HCAL

EM-CalorimeterPbGl High Threshold

Cerenkovfast trigger on e’

e/h separation

Dual-Radiator RICH

as LHCb /HERMES

TraditionalDrift-Chambers

better GEM-Tracker

Central Trackeras BaBar

Si-Vertexas Zeus

Hadronic Calorimeter


Technology choices and needed R&D

E.C. Aschenauer

Some thoughts about technologies LHC trackers have all to much radiation length

GEM trackers and ILC Si detectors would be much better important to keep radiation length in hadron direction low

ILC-TPC endplate ~30% Xo

Babar/Belle no forward detectors

Forward calorimeters small moliere radius PbWO4

especially important for hadron direction DVCSPreshower: -g p0 separation Si-WO

Central calorimeterneeds to be compact with a pointing geometry

sampling calorimeter with accordion structure

Needed R&D low mass trackers compact calorimetry for inside solenoid ion polarimetry currently at best 5% systematic uncertainty

at RHICBjoerken sum rule measurement requires ~2%


IR-Design

0.4

4 m

Q5D5

Q4

90 m

10 mrad 0.3

29 m

3.67 mrad

60 m10 20 30

0.1

88036 m

18.8

m

16.8

m

6.33 mrad4 m

Dipol

e

© D.Trbojevic

30 GeV e-

325 GeV p

125 GeV/u ions

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

Assume 50% operations efficency 4fb-1 / week

E.C. Aschenauer

Spin

rotator


A detector integrated into IR

E.C. Aschenauer

ZDC

FPD

for ERL solution need not to measure electron polarization bunch by bunch need still to integrate luminosity monitor need still to integrate hadronic polarimeters, maybe at different IP

FED

space for e-polarimetryand luminositymeasurements


Can we detect DVCS-protons and Au break up p

E.C. Aschenauer

track the protons through solenoid, quads and dipole with hector beam angular spread 0.1mrad at IR Quads +/- 5mrad acceptance Proton-beam: p’z> 0.9pz

100 GeV: ptmax < 0.45 GeV tmax < 0.2 GeV2

Detector: acceptance starts Θ > 10 / 20 mrad tmin > 1 / 4 GeV2

need more work to find a way to cover intermediate range solution could be to do the same as for the electrons swap the

dipole and quads lumi goes down

proton track Dp=10% proton track Dp=20%

Equivalent to fragmenting protons from Au in Au optics (197/79:1 ~2.5:1)

proton track Dp=40%


Quite some progress on integrating detector in machine design

Main features of detector design identified and implemented in design

BUT need more feedback on requirements from physics

groups which hopefully comes with defining the physics

program for an EIC @ the INT BNL: look into the possibilities to use existing

detectors eSTAR, ePHENIX eSTAR & ePHENIX look promising, but have some

restrictions compared to a dedicated detector

E.C. Aschenauer

and Summary

EIC INT Program, Seattle 2010 - Week 1 20E.C. Aschenauer

BACKUP


solenoid

electron FFQs100 mrad

0 mrad

ion dipole w/ detectors

(approximately to scale)

ions

electrons

IP

detectors

ion FFQs

2+3 m 2 m 2 m

Make use of a 100 mr crossing angle for ions!

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

Distance IP – electron FFQs = 3.5 mDistance IP – ion FFQs = 7.0 m

100 mr crossing angle3.5 m distance IP – electron FFQs Easy to squeeze baby-size

electron FFQs in here

Jlab: Detector/IR cartoon

E.C. Aschenauer

Slides Rolf Ent


4 on 60 11 on 60

1H(e,e’π+

)nSIDIS p

Need Particle ID for p > 4 GeV in central region DIRC won’t work, add threshold Cherenkov or RICH

Need Particle ID for well above 4 GeV in forward region (< 30o?) determines bore of solenoid

In general: Region of interest up to ~10 GeV/c mesonsMomentum ~ space needed for detection

{{

Jlab: Where do particles go - mesons

E.C. Aschenauer

Slides Rolf Ent


• EM Calorimeter (30-50 cm)

– Crystals, small area

• TOF (5-10 cm)

• RICH (60-100 cm)

– C4F8O + Aerogel

EM

Calo

rim

ete

r

Had

ron

Calo

rim

ete

r

Mu

on

Dete

cto

r

EM

Calo

rim

ete

r

Solenoid yoke + Hadronic Calorimeter

Solenoid yoke + Muon DetectorTOF

HTC

C

RIC

H

RICH

Tracking

2m 3m 2m

• IP is shown shifted left by 0.5 meter here, can be shifted

– Determined by desired bore angle and forward tracking resolution

– Flexibility of shifting IP also helps accelerator design at lower energies (gap/path length difference induced by change in crossing angle)

• Or DIRC (10 cm) + LTCC (60-80 cm)

– C4F

8O gas

– π/K: 4 - 9 GeV/c (threshold)

– e/π: up to 2.7 GeV/c (LTCC)

– K/p: up to 4 GeV/c (DIRC)

Jlab: Overview of Central Detector Layout

E.C. Aschenauer

Slides Rolf Ent


solenoid


0 mrad



ions

electrons

IP

detectors

ion FFQs

2+3 m 2 m 2 m


Detect particles with angles down to 0.5o

Need up to 2 Tm dipole bend, but not too much!

Jlab: Detector/IR cartoon

E.C. Aschenauer

Slides Rolf Ent


• Downstream dipole on ion beam line ONLY has several advantages– No synchrotron radiation

– Electron quads can be placed close to IP

– Dipole field not determined by electron energy

– Positive particles are bent away from the electron beam

– Long recoil baryon flight path gives access to low -t

– Dipole does not interfere with RICH and forward calorimeters

• Excellent acceptance (hermeticity)

solenoid


0 mrad



ions

electrons

IP

detectors

ion FFQs

2+3 m 2 m 2 m

exclusive mesons

0.2 - 2.5°

recoil baryons

4 on 30 GeV

Q2 > 10 GeV2


Slides Rolf EntJlab: Detector/IR cartoon

E.C. Aschenauer


Processes used to study the Physics

E.C. Aschenauer

exclusive /diffractive reactions

ep/A e’p’/A’VM

semi-inclusivereactionsep/A e’pX

electro-weak

reactions

inclusivereactionsep/A e’X

Close to 4pacceptance

Excellentelectron

identification

PID:to identifyHadrons

Backgroundsuppression

Detectoutgoing scattered proton

Detect very low Q2

electron

good jetidentification

excellentabsoluteand/orrelative

luminosityvery precisepolarization

measurement

high demands onmomentum and/orenergy resolutiongood vertex

resolution


Detector Requirements from Physics

Detector must be multi-purpose Need the same detector for inclusive (ep -> e’X), semi-

inclusive (ep -> e’hadron(s)X), exclusive (ep -> e’pp) reactions and eA interactions

Able to run for different energies (and ep/A kinematics) to reduce systematic errors Ability to tag the struck nucleus in exclusive and diffractive

eA reactions Needs to have large acceptance

Cover both mid- and forward-rapidity particle detection to very low scattering angle; around 1o in e

and p/A direction particle identification is crucial

e, p, K, p, n over wide momentum range and scattering angle excellent secondary vertex resolution (charm)

small systematic uncertainty for e,p-beam polarization and luminosity measurement

E.C. Aschenauer


eRHIC – Geometry high-lumi IR

1.6 m

1 32 4 5 6

0.85 m

7

10 mrad

5.4

cm

8.4

cm

10.4

cm

1 m

© D.Trbojevic

E.C. Aschenauer

Two designs of the IR exist for both low luminosity (~ 3x1033) and high luminosity (~ 2x1034) depends on distance IR to focusing quads

By using a crossing angle (and crab cavities), one can have energy-independent geometries for the IRs and no synchrotron radiation in the detectors

Big advantage in detecting particles at low angle can go as low as 0.75o at hadron side |h| < 5.5 Beam-p: y ~

6.2

m

eRHIC IR1

p /A e

Energy (max), GeV 325/130 20

Number of bunches 166 74 nsec

Bunch intensity (u) , 1011 2.0 0.24

Bunch charge, nC 32 4

Beam current, mA 420 50

Normalized emittance, 1e-6 m, 95% for p / rms for e

1.2 25

Polarization, % 70 80

rms bunch length, cm 4.9 0.2

β*, cm 5 5

Luminosity, cm-2s-1 1.46 x 1034

(including hour-glass effect h=0.851)

Luminosity for 30 GeV e-beam operation will be at 20% level


STAR @ RHIC

Heavy Flavor Tracker (2013)

Tracking: TPC

Forward Gem Tracker(2011)

Electromagnetic Calorimetry:BEMC+EEMC+FMS(-1 ≤ η ≤ 4)

Particle ID: TOF

Full azimuthal particle identification over a broad range in pseudorapidity

Upgrades:Muon Tracking Detector HLT

E.C. Aschenauer


Kinematics at 4+100

Scattered electron Scattered jet

4x100 open kinematics: scatters the electron and jet to mid-rapidityForward region (FMS): Electron either Q2 < 1 GeV, or very high x and Q2

Jet either very soft or very hardNote: current thinking has hadron in the blue beam: optimized for high x and Q2

E.C. Aschenauer


Current PHENIX Detector at RHIC

MPC 3.1 < | h | < 3.9 2.5o < Q < 5.2o Muon Arms 1.2 < | h | < 2.4 South: 12o < Q < 37o

North: 10o < Q < 37o

Central Arms | h | < 0.35 60o < Q < 110o

e-

electrons will not make it to the south muon arm to much material

would like to have hadrons in blue beam and leptons in yellow beam direction

E.C. Aschenauer


What will the current PheniX see4x100

pe: 0-1 GeV pe: 1-2 GeV pe: 2-3 GeV pe: 3-4 GeV

4x100 4x100

Current PheniX detector not really useable for

DISacceptance not matched to DIS kinematics

BUT ….

E.C. Aschenauer


HCALEMCAL

Preshower

The new PheniX Spectrometer

Coverage in |h| =< 4 (2o < q < 30o) 0.1 < Q2 < 100 (5o – 175o) need an open geometry detector planes for next decadal plan

replace current central detector with a new one covering |h| =< 1replace South muon arm by a endcap spectrometer

60cm

2T SolenoidEMCAL

HCAL

Silicon TrackerVTX + 1 layer

Silicon TrackerFVTX

1.2 < h < 2.7 8o < q < 37o

North Muon Arm

RICH

68cm

IP

80cm

145cm

5o @ 2m 17.4 cm dy

E.C. Aschenauer

Summary:

the new PheniX detector can make

important measurements

in ep/eA

Lets integrate it fully into the design

and the next decadal plan

Documents

E.C. AschenauerEIC INT Program, Seattle 2010 - Week 11