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Some thoughts to stimulate Discussion. Detector Requirements from Physics. ep-physics the same detector needs to cover inclusive (ep -> e’X), semi-inclusive (ep -> e’hadron(s)X) and exclusive (ep -> e’p p) reactions energy variability p : 50 – 250/325 e : 4 - 20 - PowerPoint PPT Presentation
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EICC @ Stony Brook, January 2010
1
Some thoughts to stimulateDiscussion
E.C. Aschenauer
EICC @ Stony Brook, January 2010 2
Detector Requirements from Physics
E.C. Aschenauer
ep-physics the same detector needs to cover inclusive (ep -> e’X), semi-
inclusive (ep -> e’hadron(s)X) and exclusive (ep -> e’pp) reactions
energy variability p: 50 – 250/325 e: 4 - 20 large acceptance absolutely crucial (both mid and forward-rapidity) particle identification is crucial
e, p, K, p, n over wide momentum range and scattering angleexcellent secondary vertex resolution (charm)
particle detection to very low scattering angle around 1o in e and p/A direction
in contradiction to strong focusing quads close to IP small systematic uncertainty (~1%/~3%) for e/p polarization
measurements very small systematic uncertainty (~1%) for luminosity
measurement eA-physics
requirements very similar to epchallenge to tag the struck nucleus in exclusive and diffractive reactions.difference in occupancy must be taken into account
EICC @ Stony Brook, January 2010 3
Energies Simulated in RAPGAP
Beam EnergiesEe + Ep [GeV]
Center-of-mass Energy [GeV]
Events Produced
4+50 28.34+100 40.010+50 44.74+250 63.3
10+100 63.3 One million20+50 63.3
20+100 89.410+250 10020+250 141
E.C. Aschenauer
EICC @ Stony Brook, January 2010 4
(M)eRHIC Luminosities
E.C. Aschenauer
Some luminosity numbers:for MeRHIC without CEC 4 x 250: 1x1032 cm-2s-1
for MeRHIC with CEC 4 x 250: 1x1033 cm-2s-1
for eRHIC with CEC: 20 x 325: 2.8x1033 cm-2s-1
30 x 325 with b* of 5cm: 1.4x1034 cm-2s-1
as the the luminosity does not depend on the energy of electron beam youcan write it as for eRHIC with CEC: 2.8 1033* Ep/250 cm-2s-1
so you can easily scale it going to 20x100 for example
so for MeRHIC assuming 50% operations efficiency one week corresponds to0.5 * 604800(s in a week) * (1x1032 cm-2s-1) = 3*1037 cm-1 so 30pb-1
for eRHIC with CEC we collect in one week ~1fban 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
BNL S&T-Review, July 2009 5
The √s vs. minimum luminosity landscape
E.C. Aschenauer
semi-inclusive DIS
inclusive DIS
Diffraction
electro-weak
4x10010x100 20x100 20x250
exclusive DIS (DVCS)
exclusive DIS (PS & VM)
4x50
H1/ZEUS:~1031cm-2s-1
Hermes:5x1031-1033
W2-dependence of c.s. neglected
EICC @ Stony Brook, January 2010 6
Momentum vs. theta of scat. electron
Proton Energy50 GeV 100 GeV 250 GeV
Elec
tron
Ene
rgy
4
GeV
1
0 G
eV
2
0 G
eV
E.C. Aschenauer
As more symmetricbeam energies
as more thescattered lepton
goes forward
EICC @ Stony Brook, January 2010 7E.C. Aschenauer
4x50
4x10
04x
250
pe: 0-1 GeV pe: 1-2 GeV pe: 2-3 GeV pe: 3-4 GeV
Q2>1GeV2 20o
after 1m ~35cm away from beam pipe
Momentum vs. angle of pions
Same CM energy (63.3 GeV)
What do we see: For DIS: distribution is more “smeared”
as energy balance becomes more symmetric
For diffractive: majority of pions at easily accessible angles, either forward or backward depending on proton/electron energy
8
EICC @ Stony Brook, January 2010 9
t for exclusive VM vs p’ angle
E.C. Aschenauer
4 x 50 4 x 100
4 x 250
very strong correlation between t and “recoiling” proton angle Roman pots need to be very well integrated in the lattice resolution on t!
t=(p4-p2)2 = 2[(mpin.mpout)-(EinEout - pzinpzout)] t=(p3–p1)2 = mρ2-Q2 - 2(Eγ*Eρ-pxγ*pxρ-pyγ*pyρ-
pzγ*pzρ)
EICC @ Stony Brook, January 2010 10
IR-Design for MeRHIC IP-2
E.C. Aschenauer
no synchrotron shielding included allows p and heavy ion decay product tagging IP-2: height beam-pipe floor ~6’ (with digging ~10’)
EICC @ Stony Brook, January 2010 11
First ideas for a detector concept
E.C. Aschenauer
Dipole3Tm
Dipole3Tm
Solenoid (4T)
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 radiation length very critical low lepton energies
EICC @ Stony Brook, January 2010 12
MeRHIC Detector in Geant-3
E.C. Aschenauer
DIRC: not shown because of cut; modeled following Babar no hadronic calorimeter in barrel, because of vertical space @ IP-2
Drift Chambers central tracking
ala BaBar
Silicon Stripdetectorala Zeus
EM-CalorimeterLeadGlas
High ThresholdCerenkov
fast trigger on e’e/h separation
Dual-Radiator RICH
ala HERMES
Drift Chambers ala HERMES FDC
EICC @ Stony Brook, January 2010 13E.C. Aschenauer
BACKUP
EICC @ Stony Brook, January 2010E.C. Aschenauer
14
STAR
PHENIX
2 x 200 m SRF linac4 (5) GeV per pass5 (4) passes
Polarized e-gun
Beamdump
4 to 5 vertically separatedrecirculating passes
Cohe
rent
e-
cool
er
5 mm
5 mm
5 mm
5 mm
20 GeV e-beam16 GeV e-beam
12 GeV e-beam
8 GeV e-beam
Com
mon
vac
uum
ch
ambe
r
Gap 5 mm total0.3 T for 30 GeV
(M)eRHICdetector
MeRHIC
detector
10-20 GeV e x 325 GeV p 130 GeV/u Au
possibility of 30 GeV @low current operation
ERL-based eRHIC Design
EICC @ Stony Brook, January 2010 15
Zeus @ HERA I
E.C. Aschenauer
EICC @ Stony Brook, January 2010 16
Zeus @ HERA II
E.C. Aschenauer
EICC @ Stony Brook, January 2010 17
Hera I vs. Hera II
E.C. Aschenauer
Focusing Quads close to IPProblem for forward acceptance
EICC @ Stony Brook, January 2010 18
ions
electrons
solenoid dipole bendingscattered protons “up”
IP withcrossing angle electron FFQs
ion FFQs
Distance from IP to electron FFQ: 6 m to ion FFQ: 9m
Electron FF quad
Distance from IP
length Field strength
Beam size sx@ 3 GeV
Beam size sy@ 3 GeV
Quad 1 6.0 meter 50 cm -1.14 kG/cm
5 mm 4 mm
Quad 2 6.75 meter
120 cm 0.71 kG/cm
8 mm 3 mm
Quad 3 8.7 meter 50 cm -0.75 kG/cm
4 mm 4 mm
Modest electron final focusing quad field requirements quads can be made small
ELIC Detector/IR Layout
E.C. Aschenauer
by R. Ent
EICC @ Stony Brook, January 2010 19
8 meters (for scale)
140 degrees
Tracking
TOF
dipole
solenoid
RICH
ECAL
DIRC
HCAL
HTCC
Offset IP?
Ion beame beam
dipole1st (small) electron FF quad @ 6 m
ELIC detector cartoon - Oct. 09
E.C. Aschenauer
Additional electron detection (tracking, calorimetry) for low-Q2 physics not on cartoon
by R. Ent
EICC @ Stony Brook, January 2010 20
Event kinematics produced hadrons (p+)
E.C. Aschenauer
DIS
DIFFRACTIVE
4x50 4x250
withoutmagneticfield
DIS:smalltheta important
20x250