E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
1
eRHIC Scope
RHIC
Electron accelerator
p
Unpolarized and
polarized leptons
4-20 (30) GeV
eee+
70% e- beam polarization goal
polarized positrons?
Polarized protons
50-250 (325) GeV
Light ions (d,Si,Cu)
Heavy ions (Au,U)
50-100 (130) GeV/u
Polarized light ions
(He3) 215 GeV/u
Center mass energy range: √s=28-200 GeV; L~100-1000xHera
longitudinal and transverse polarisation for p/He-3 possible
Mission: Studying the Physics of Strong Color Fields
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
2
The Relativistic Heavy-Ion Collider @ BNL
12 o’clock proposed
PHOBOS
BRAHMS
RHIC
PHENIX
v = 0.99995c = 186,000 miles/sec
STAR
RF
EBIS
BOOSTER
ERL Test
Facility
AGS
TANDEMS
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
3
The 1st/2nd incarnation of a staged eRHIC
Gap 5 mm total
0.3 T for 30 GeV
Energy, GeV
p (A)
e
250
(100)
4
dump
111
Bunch intensity (u)
, 1011
2.0
0.3
1
2.0
(3)
0.24
Bunch charge, nC
32
5
32
4
Beam current, mA
320
50
420
Normalized
emittance, 1e-6
m, 95% for p /
rms for e
166
e-gun
Number of bunches
15WHY
IP-12?
73
1.2
3 pass
4 GeV ERL
10-20 GeV e x 325 GeV p
130 GeV/u Au
possibility of 30 GeV @
low current operation
50
<10>
20 GeV
e-beam
16 GeV
e-beam
25
70
80
rms bunch length,
cm
20
0.2
β*, cm
50
50
0.1 -> 1
with CeC
E.C. Aschenauer
5 mm
5 mm
12 GeV
 have Experimental Hall @ IP-12 size of STARe-beam
Polarization, %
Luminosity, x
1033, cm-2s-1
2 x 200 m SRF linac
4 (5) GeV per pass
5 (4) passes
Common vacuum
chamber
MeRHIC
eRHIC with
CeC
eRHIC
MeRHIC
p (A) detector
e
detector
325
20
<30>
(125)
Beam Polarized
fully staged detector from MeRHIC to eRHIC 8 GeV
5 mm
e-beam
70
80
vertical space much bigger (room for HCal)
5 mm
to buy magnets only once
4.9need 0.2
can stage detector components, i.e. hadronic calorimeter
25
25
no moving of components (IP2  IP12)
4 to 5 vertically
STAR
STAR
systematics reduced  same detector
for all energies
separated
2.8
recirculating passes
EIC EW Meeting, W&M, VA, May 2010
4
The latest design of eRHIC
Common vacuum chamber
eRHIC staging all-in tunnel
30 GeV
25 GeV
20 GeV
Polarized e-gun
eRHIC detector
Beam-dump
15 GeV
10 GeV
6 pass 2.5 GeV ERL
5 GeV
0.1 GeV
Common vacuum chamber
27.5 GeV
22.5 GeV
17.5GeV
12.5
GeV
7.5 GeV
2.5 GeV
RHIC: 325 GeV p
or 130 GeV/u Au
The most
cost
effective
design
STAR
100m
|--------|
5
LINAC SS and ARC Design
200 m ERL Linac
e+ ring
1.27 m beam high
© V. Litvinenko
30 GeV e+ ring
30 GeV ERL
HE ERL
passes
LE ERL
passes
6 passes
1.27 m beam high
30 GeV
25 GeV
20 GeV
15 GeV
10 GeV
5 GeV
© V. Litvinenko
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
6
IR-Design
10
20
0.329 m
0.188036 m
0.44 m
eRHIC - Geometry high-lumi IR with β*=5 cm, l*=4.5 m
and 10 mrad crossing angle
30 GeV e-
30
60 m
m
90 m
© D.Trbojevic
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
7
eRHIC – Geometry high-lumi IR
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
m
1
2
Beam current, mA
3
4
5
Normalized emittance, 1e-6 m, 95% for p / rms
for e
6
420
1.2
10 mrad
7
© 50
D.Trbojevic
25
 Two designs of the IR exist for both low luminosity (~
and high
Polarization,
80
luminosity% (~ 2x1034) depends on distance IR to70focusing quads
length,
cm
4.9 can have energy0.2
rms
Bybunch
using
a crossing
angle (and crab cavities), one
independent geometries for the IRs and no synchrotron radiation in the
β*, cm
5
5
detectors
1.46 x 1034
Luminosity,
Big advantage
in
detecting
particles
at
low
angle
-2
-1
cm s
(including hour-glass effect
 can
as e-beam
low asoperation
0.75owillatbehadron
side  |h|
< h=0.851)
5.5 Beam-p: y ~ 6.2
Luminosity
for go
30 GeV
at 20% level
E.C. Aschenauer
3x1033)
EIC EW Meeting, W&M, VA, May 2010
8
(M)eRHIC Luminosities
Old Design:
for MeRHIC without CEC 4 x 250:
for MeRHIC with CEC
4 x 250:
for eRHIC with CEC:
20 x 325:
New Design:
for eRHIC with CEC:
1x1032 cm-2s-1
1x1033
cm-2s-1
2.8x1033 cm-2s-1
20 x 325 with b* of 5cm:
1.4x1034 cm-2s-1
as the the luminosity does not depend on the energy of electron beam you
can write it as
for eRHIC (new design):
1.4 1034* Ep/325 cm-2s-1
so you can easily scale it going to 20x100 for example
so for eRHIC assuming 50% operations efficiency one week corresponds to
0.5 * 604800(s in a week) * (1.4x1034 cm-2s-1) = 4*1039 cm-1 so 4000pb-1
an operations efficiency of 50% is low, but conservative at this moment.
For EIC systematic errors will be the limiting factor
i.e., g1, FL, Dg, Dq
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
9
Questions about QCD
 Confinement of color, or why are there no free quarks and gluons
at a long distance?
A very hard question to answer

What
is answer:
the quark-gluon structure inside a hadron?
Lets
try to
Probes
to “see”
andgluons
“locate”
quarks
and gluons, without
 What
is the
role of
and the
gluon
self-interactions
in nucleons and nuclei?
 What
is the them
internal
landscape ofwith
thetheir
nucleons?
disturbing
or interfering
dynamics?
 What
is the nature
of theform
spin of
the neutral
proton? hadrons?
 How
do quarks
and gluons
color
 What is the three-dimensional spatial landscape of nucleons?
Probes
to “monitor”
the hadronization
process?
 What
governs
the transition
of quarks and
gluons into pions and nucleons?
 How to understand the spin of a hadron?
Hadrons are a composite particle of quarks and gluons
 What is the physics behind the QCD mass scale?
The key to the solution
The Gluon
 It represents the difference between QED and QCD
 Can’t “see” it directly, but,
it is behind the answers to all these questions
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
10
The √s vs. minimum luminosity landscape
W2-dependence of
c.s. neglected
Diffraction
exclusive DIS (PS & VM)
electro-weak
H1/ZEUS:
~1031cm-2s-1
exclusive DIS (DVCS)
semi-inclusive DIS
Hermes:
5x1031-1033
inclusive DIS
4x50 4x100 10x100 20x100
E.C. Aschenauer
20x250
EIC EW Meeting, W&M, VA, May 2010
11
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
EIC EW Meeting, W&M, VA, May 2010
12
Momentum vs. theta of scat. electron
Electron Energy
10 GeV
20 GeV
50 GeV
Proton Energy
100 GeV
250 GeV
4 GeV
As more symmetric
beam energies
as more the
scattered lepton
goes forward
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
13
pe: 1-2 GeV
pe: 2-3 GeV
pe: 3-4 GeV
No dependence on hadron beam energy
Q2>0.1GeV2
4GeV  >5o
10GeV  >2o
20GeV  >1o
4x250
4x100
4x50
pe: 0-1 GeV
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
14
Momentum vs. angle of pions
What do we see:
Same CM energy  For DIS: distribution is more “smeared” as
energy balance becomes more symmetric
(63.3 GeV)
 For diffractive: majority of pions at easily
accessible angles, either forward or backward
depending on proton/electron energy
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
15
t for exclusive VM vs p’ angle
t=(p4-p2)2 = 2[(mpin.mpout)-(EinEout - pzinpzout)]
t=(p3–p1)2 = mρ2-Q2 - 2(Eγ*Eρ-pxγ*pxρ-pyγ*pyρ-pzγ*pzρ)
4 x 50
4 x 100
very strong correlation between
t and “recoiling” proton angle
 Roman pots need to be very
well integrated in the lattice
 resolution on t!
E.C. Aschenauer
4 x 250
EIC EW Meeting, W&M, VA, May 2010
16
A detector integrated into IR
a lot of space
for polarimetry
and luminosity
measurements
ZDC
FPD
FED
 Dipoles needed to have good forward momentum resolution
 Solenoid no magnetic field @ r ~ 0
 DIRC, RICH hadron identification  p, K, p
 high-threshold Cerenkov  fast trigger for scattered lepton
EIC EW
Meeting, W&M, VA, May
E.C.
Aschenauer
 radiation length
very
critical  low lepton
energies
2010
17
Can we detect DVCS-protons and Au break up p
 track the protons through solenoid, quads and dipole with hector
proton track Dp=10%
proton track Dp=20%
proton track Dp=40%
Equivalent to fragmenting protons
from Au in Au optics (197/79:1 ~2.5:1)
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
18
eRHIC Detector in Geant-3
central
tracking
ala BaBar
Silicon Strip
detector
ala Zeus
Drift
Chambers
Drift
Chambers ala HERMES FDC
EM-Calorimeter
LeadGlas
High Threshold
Cerenkov
fast trigger on e’
e/h separation
Dual-Radiator
RICH
ala HERMES
 DIRC: not shown because of cut; modeled following Babar
 no hadronic calorimeter in barrel yet
 investigate ILC technology to combine mID with HCAL
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
19
MeRHIC Detector in Geant-3
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
20
More Detector Concepts in the same framework
“eSTAR”
Detector optimized for
diffractive physics
by Allen Caldwell
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
21
STAR @ RHIC
Tracking: TPC
Particle ID: TOF
Electromagnetic
Calorimetry:
BEMC+EEMC+FMS
(-1 ≤  ≤ 4)
Upgrades:
Muon Tracking
Detector
HLT
Heavy Flavor Tracker
(2013)
E.C. Aschenauer
Full azimuthal particle identification
EW Meeting,
VA, May 2010
over aEIC
broad
range W&M,
in pseudorapidity
Forward Gem
Tracker
(2011)
22
Kinematics at 4+100
Scattered electron
Scattered jet
4x100 open kinematics: scatters the electron and jet to mid-rapidity
Forward region (FMS): Electron either Q2 < 1 GeV, or very high x and Q2
Jet either very soft or very hard
Note: current thinking has hadron in the blue beam: optimized for high x and Q2
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
23
Current PHENIX Detector at RHIC
MPC
Muon Arms
South:
North:
Central Arms
3.1 < | h | < 3.9
2.5o < Q < 5.2o
1.2 < | h | < 2.4
12o < Q < 37o
10o < Q < 37o
| h | < 0.35
60o < Q < 110o
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
24
e-
EIC EW Meeting, W&M, VA, May 2010
What will the current PheniX see
pe: 1-2 GeV
pe: 2-3 GeV
pe: 3-4 GeV
4x100
pe: 0-1 GeV
Current PheniX detector
not really useable for
DIS
acceptance not matched to DIS kinematics
BUT ….
4x100
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
4x100
25
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
=< 1
North
Muon|h|
Arm
145cm
replace South muon arm by a endcap spectrometer
HCAL
80cm
HCAL
EM
CAL
EMCAL
Preshower
R
I
C
H
IP
68cm
60cm
2T Solenoid
Silicon Tracker
VTX + 1 layer
Silicon Tracker
FVTX
1.2 < h < 2.7
8o < q < 37o
5o @ 2m
17.4 cm dy
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
26
Summary
 A lot of change/progress since the last EIC Collaboration
meeting
 new eRHIC design more elegant and staging is very naturaly
included
 working on costing of the new version
 test many detector options eSTAR, ePHENIX and a dedicated
detector
eSTAR & ePHENIX look promising with some restrictions
 need to adjust the dedicated detector design fully to the new
IR design
 will integrate luminosity and e/p-polarisation measurements on
the next step
 Need input from the EW community what is required for
detector, machine and IR design
 Submitted first detector LDRD to BNL  high resolution
vertex detector based on CMOS pixel
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
27
Quads for β*=5 cm
© B.Parker
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
28
Luminosities in electron-hadron collisions
e+A facilities
© 2010 Plot by A.Accardi
except
eRHIC luminosity by V. Litvinenko
eRHIC II
eRHIC
ELIC
HERA II
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
29
Questions about QCD (biased list)
 Confinement of color, or why there is no free quarks and gluons at
a long distance?
A very hard question to answer
 What is the quark-gluon structure inside a hadron?
Probes to “see” and “locate” the quarks and gluons, without
disturbing them or interfering with their dynamics?
 How quarks and gluons form color neutral hadrons?
Probes to “monitor” the hadronization process?
 How to understand the spin of a hadron?
A composite particle of quarks and gluons
 What is the physics behind the QCD mass scale?
…
The key to the solution
The Gluon
 It represents the difference between QED and QCD
 Can’t “see” it directly, but,
it is behind the answers to all these questions
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
30
Energies Simulated for kinematics
Beam Energies
Ee + Ep [GeV]
4+50
4+100
Center-of-mass
Energy
[GeV]
28.3
40.0
10+50
4+250
10+100
20+50
44.7
63.3
63.3
63.3
20+100
10+250
20+250
89.4
100
141
E.C. Aschenauer
Events
Produced
One million
EIC EW Meeting, W&M, VA, May 2010
31
The 1st incarnation from a staged eRHIC
10-20 GeV e x 325 GeV p
130 GeV/u Au
possibility of 30 GeV @
low current operation
Polarized
e-gun
Beam
dump
20 GeV
e-beam
16 GeV
e-beam
Common vacuum
chamber
Gap 5 mm total
0.3 T for 30 GeV
2 x 200 m SRF linac
4 (5) GeV per pass
5 (4) passes
12 GeV
e-beam
8 GeV
e-beam
5 mm
5 mm
5 mm
5 mm
STAR
E.C. Aschenauer
4 to 5 vertically
separated
recirculating passes
EIC EW Meeting, W&M, VA, May 2010
32
IR-Design for MeRHIC IP-2
 synchrotron shielding omitted
 allows p and heavy ion decay product tagging
 IP-2: height beam-pipe floor ~6’ (with digging ~10’)
 limits detector design  no HCal in central detector
E.C. Aschenauer
EIC EW Meeting, W&M, VA, May 2010
33
The latest design of eRHIC
eRHIC staging all-in tunnel
energy of electron beam is increasing
from 5 GeV to 30 GeV by building-up the linacs
eRHIC detector
The most
cost
effective
design
2 SRF linac
1 -> 5 GeV per pass
4 (6) passes
Vertically separated
recirculating passes.
# of passes will
be chosen to optimize
eRHIC cost
Common vacuum chamber
Gap 5 mm total
0.3 T for 30 GeV
RHIC: 325 GeV p
or 130 GeV/u Au
eSTAR
E.C. Aschenauer
© V. Litvinenko
EIC EW Meeting, W&M, VA, May 2010
20 GeV
e-beam
15 GeV
e-beam
10 GeV
e-beam
5 GeV
e-beam
5 mm
5 mm
5 mm
5 mm
34