polarized beams in rhic a.zelenski, bnl pstp 2011, september 12, st.petersburg
TRANSCRIPT
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Polarized beams in RHICA.Zelenski, BNL
PSTP 2011, September 12, St.Petersburg
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RHIC High-Luminosity (Polarized) Hadron Collider.
2010-100 ,31, 19.5,3.9, 5.5 GeV
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RHIC: the “Polarized” Collider
STARPHENIX
AGS, 24GeVLINAC
BOOSTER, 2.5 GeV
Pol. H- ion source
Spin Rotators
20% Snake
Siberian Snakes
200 MeV polarimeter
RHIC pC “CNI” polarimeters
RHIC
Absolute H-jetpolarimeter
Design goal - 70% Polarization L max = 1.6 1032 s-1cm-2 50 < √s < 500 GeV
AGS pC “CNI” polarimeter
5% Snake
Polarization facilities at RHIC.Polarization facilities at RHIC.
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Optically-Pumped Polarized H- Ion Source (OPPIS) at RHIC,(originally developed in collaboration between KEK, BNL,
TRIUMF and INR Moscow).
Optically-Pumped Polarized H- Ion Source (OPPIS) at RHIC,(originally developed in collaboration between KEK, BNL,
TRIUMF and INR Moscow).
RHIC OPPIS produces reliably 0.5-1.0mA(maximum 1.6 mA) polarized H- ion current.Pulse duration 400 us.Polarization at 200 MeV P = 85-90%.
Beam intensity (ion/pulse)
routine operation:Source - 1012 H-/pulseLinac (200MeV) - 5∙1011
AGS - 1.7∙1011
RHIC - 1.4∙1011
(protons/bunch).A beam intensity greatly exceeds RHIC limit, which allowed strong beam collimation in the Booster, to reduce longitudinal and transverse beam emittances.
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Schematic Layout of the RHIC OPPISSchematic Layout of the RHIC OPPIS
29.2 GHz ECR proton source29.2 GHz ECR proton source
SCS solenoidSCS solenoid
Probelaser
Na-jetIonizer
cell
Na-jetIonizer
cell
Pumpinglaser
CryopumpsCryopumps
Sona-transition
Rb-cellSCS -solenoid
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Depopulation Optical Pumping
5S1/2
5P1/2
λ = 795 nm
Circularly
Polarized lig
ht
MJ = -1/2 MJ = +1/2
Spontaneous
decays.
nLJ
~ 100% polarized Rb
atoms!
1.56 eV
W. Happer, Rev. Mod. Phys. 44, 170 (1972)
relaxation
Optical pumping application is limited by available laser wavelenghes!?Recent progress in laser technology is very promising for new applications.
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Optical pumping of alkali metals
2S1/2
5/2
3/2
F =5/2
2P1/2
3/2
8Li I = 2
Li 671 nmNa 590 K 770 Rb 795 Cs 894 Fr 817
Typical polarization = 60 – 70%
381 MHz
mF-5/2 -3/2 -1/2 1/2 3/2 5/2
Valence electron absorbs light tranfers polarization to nucleus via hyperfine coupling
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Collinear Optical Pumping polarizer at TRIUMF
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Faraday rotation polarimeter of Rb vapor.Faraday rotation polarimeter of Rb vapor.
Θp-optical pumping –on.Θ0-optical pumping -off.
PD1
PD1=I0 sin θp
PD2=I0 cos θp
PRb= (θp- θ0)/ θ0
PD2
Cr:LISAF pumping laser at795 nm
Rb-cell
λ/2
Linear polarized probe laser beam at 780 nm.
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Polarized H- ion current pulse out of 200 MeV linac.
Polarized H- ion current pulse out of 200 MeV linac.
Faradey rotation polarization sinal.
500 uA cuurentAt 200 MeV.85-hole ECRSource for themaximum polarization.
400 uS 12·1011 -polarized H- /pulse.
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EBIS ionizer for polarized 3He gas (proposal).EBIS ionizer for polarized 3He gas (proposal).
He(2S)→He(1S)
He(2S)→He(1S)
He-3 metastability-exchange polarized cell
P - 80-90%.
Pumping laser 1083 nm.
Pumping laser 1083 nm.
EBIS-ionizer,
B~ 50 kG
EBIS-ionizer,
B~ 50 kG
RFQ
Linac
Booster
AGS
RHIC
RFQ
Linac
Booster
AGS
RHIC
He-transfer line.
Valve. ~50·1011
3He /pulse.
2.5·1011 He++/pulse
Polarization by optical pumping Ionization
1.5·1011 He++/pulse
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AGS Cold Snake installed.AGS Cold Snake installed.
The two-snake solution provides better spin matching at injection and extraction.
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PHENIX and STAR
STAR
STAR:Large acceptance with azimuthal symmetryGood tracking and PIDCentral and forward calorimetry
PHENIX:High rate capabilityHigh granularityGood mass resolution and PIDLimited acceptance
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Intermediate bozons W± - can be produced directly in electroweak processes in
collisions of polarized proton beams of √S= 500 GeV energy at RHIC. In this case parity-violating AL can be as large as 50% and spin-correlation can be
used for studies of different flavor quark contribution to the proton spin.
Sea-quarks polarization studies via intermediate boson W± Production at RHIC, √S= 500 GeV.
u
d
u +d W+ , d +u W-
W +
Spinning Proton Spinning Proton
Spinning Quarks or Gluons
Quark, Gluon, Photon,Electron or Neutrino fromW or Z Decay
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2013 HP8 Measure flavor-identified q and q contributions to the spin of the proton via the longitudinal-spin asymmetry of W production.
Initial 500 GeV p+p run already demonstrates W reconstruction capabilities in STAR and PHENIX, with only ~10 pb1.
W asymmetry measurements with power to discriminate among antiquark distribution models require ~300 pb1 and >60% polariz’n.
u and d polarizations predicted to be substantially different in many nucleon structure models.
Initial 500 GeV p+p run already demonstrates W reconstruction capabilities in STAR and PHENIX, with only ~10 pb1.
W asymmetry measurements with power to discriminate among antiquark distribution models require ~300 pb1 and >60% polariz’n.
u and d polarizations predicted to be substantially different in many nucleon structure models.
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RHIC luminosity in Run-2011
Bunch intensity ~ 1.6 *1011 proton/bunch
Peak luminosity ~1.5*1032 cm2 s
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Polarized beam luminosity.
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Foundation of the RHIC Spin Physics.
High-intensity polarized proton source.
“Siberian snakes” to preserve polarization.
P-P and P-Carbon CNI polarimeters.
Theoretical “tools”: QCD calculations.
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Polarized Proton Polarimetry from the Source to RHIC energies.
A polarimeter has to satisfy the following:
Beam polarization monitor for Physics ( < 5 % )Several samples over a reasonable time period, one fillBeam polarization diagnostic and Machine tuning tool Sample on demand and online, fast/within minutes Low systematic errors.A large dynamic range & Energy independenceLarge analyzing power, large cross section, & low backgroundReasonable Cost.
Unlike electron polarimeters where processes are calculable, proton reactions rely on experimental verification specially at high energies.
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Measuring the beam polarization
In accelerators, the stable spin direction is normally vertical (up/down).
We measure using a nuclear reaction in a plane that is perpendicular to the polarization direction.
NL and NR are the number of scatters to the left and right.
A: is the analyzing power of the reaction
The statistical error in the measurement for PA << 1 is
The polarimeter figure of merit (to optimize) is A2
: is the cross section of the reaction
PA
N N
N N
L R
L R
1
PA N NL R
1 1
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Polarized beams at RHIC.Polarized beams at RHIC.
OPPIS
LINAC
Booster
AGS
RHIC
1.5-1.7 p/bunch, P ~65-70%
10 10∙ 11(maximum 40 10∙ 11) polarized H- /pulse.
5 10∙ 11 polarized H- /pulse at 200 MeV, P=85-90%
2 10∙ 11 protons /pulse at 2.3 GeV
Figure of merit for the double spin Asymmetry Collisions is ~ P4 ∙L
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Polarimetry at RHIC
Faraday rotation polarimeter Lamb-shift polarimeter 200 MeV - absolute polarimeter AGS p-Carbon CNI polarimeter RHIC p-Carbon CNI polarimeter RHIC - absolute H-jet polarimeter Local polarimeters at STAR and PHENIX
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SCHEMATIC LAYOUT OF THE RHIC OPPIS.SCHEMATIC LAYOUT OF THE RHIC OPPIS.
29.2 GHz ECR proton source29.2 GHz ECR proton source
SCS solenoidSCS solenoid
Probelaser
Na-jetIonizer
cell
Na-jetIonizer
cell
Pumpinglaser
CryopumpsCryopumps
Correction coil
Sona-shield
Rb-cellSCS -solenoid
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Proton Lamb-shift polarimeter .Proton Lamb-shift polarimeter .
H- → H+ → H(2S)
B=575 G
La(10.2eV) -121.6 nm
H(2S)
• N+ =N0(1+P) / 2• N- = N0(1-P) / 2• P=2 (N+-N-)/(N+ +N-)
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OPPIS Lamb-shift polarimeter.OPPIS Lamb-shift polarimeter.
He-ionizer cell
Na-cell, spin-filterand L detectorare placed inside thevacuum chamber.
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Polarization at Lamb Shift Polarimeter on 2/01/07 @ 10:34:58(blue), 12:14(red) & 11:25(green) (I_ion = 225 A. Sona Collimator Dia. = 12 mm)
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
-6.0 -5.5 -5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
Set Point (1 = 25 A)
Pol
ariz
atio
n
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Polarized injector, 200 MeV linac and injection lines.Polarized injector, 200 MeV linac and injection lines.
OPPIS
200 MeV polarimeter
Polarization direction is adjusted vertically in the 750 keV beamline by the solenoidal spin -
rotator.
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Layout of the 200 MeV proton polarimeter, (2010)
16.2 deg
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Polarimeters after the 200 MeV Linac
p-Carbon and p-D polarimetersp-Carbon and p-D polarimeters
D-recoil arm
12 deg. Proton arms
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Proton-Carbon ElasticScattering at 200 MeV.
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Measurements of the cross section and analyzing power
for proton scattering from 12C at 200 MeV.
The blue (green) curves correspond to protons exiting from the ground (4.44-MeV) state.
The black curve represents the sum of the two data sets.
Edward J. Stephenson, 10/22/2009
16.2deg
~40mb/sr
~5mb/sr
~80%
Notes on the Calibration of the 200-MeV Proton Polarization
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Ay=99.96+/0.02%
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elastic
GEANT calculation of pC polarimeter for 200MeV proton beam
Collimator Absorber
Sc1 Sc2 Sc3
inelastic
Ep=198.7MeV
Ep=194.3MeV
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Cu from 0 to 9mm(step by 1mm)
Cu from 0 to 1mm(step by 0.1mm)
Detector and variable absorber setup
for 200 MeV proton beam.
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195.6 Mev
200.0 Mev
Counting rate (S1^S2) vs. Cu absorber thickness.
~20
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Measured Analyzing Power vs length of absorber.
Ay(pC) =0.62+/-0.02
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Measured Analyzing Power vs length of absorber
Cu absorber thickness, mm
Ay(pC) =0.62+/-0.02
Ay(pC) =0.620+/-0.005
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LINAC energy measurements.
Energy measurement by calibrated bending magnet in the Linac HEBT.
Comparison with energy measurement in Booster.
Laser stripping.
Energy stability monitoring in the 200 MeV polarimeter.
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Counting rate (S1^S2/S3) vs Cu absorber thickness.
200.0 Mev
195.6 Mev
~12
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Vertical 16.20 detector
Horizontal 120 detector
Polarization vs current of the spin rotator.
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80.85+/-0.09%
80.29+/-0.019%
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Summary.
1. Elastic proton-Carbon scattering (at 16.2 deg. angle) is used in a new polarimeter setup. Analyzing power at 200 MeV is 99.35%.
2. The elastic scattering is used for calibration of inclusive 12 deg. polarimeter arm:
3. Rate in 16 deg arms is ~ 10 event/pulse (12 deg ~300);
4. Ratio N(Sc1^Sc2)/N(Sc1^Sc3) is used for the beam energy monitoring.
Ay (pC) =0.620+/-0.005.
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Proton-Carbon CNI polarimeters in AGS and RHIC.
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October 6-10, 2008 A.S. Belov, A. N. Zelenski, SPIN2008, USA
BRAMS
STARPHENIX
AGSLINAC
BOOSTER
Pol. H- ion source
Spin Rotators
10-20% Snake
Siberian Snakes
200 MeV polarimeter
RHIC pC “CNI” polarimeters
PHOBOS
RHIC
Absolute H-jetpolarimeter
Design goal - 70% Polarization, Lmax = 1.6 1032 s-1cm-2 , 50 √s 500 GeV
AGS pC “CNI” polarimeter
Polarization facilities at RHIC. Polarimeters.Polarization facilities at RHIC. Polarimeters.
5.9% Snake
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p-Carbon Polarimetry at RHICp-Carbon Polarimetry at RHIC
Polarized proton Recoil carbon
90º in Lab frame
Carbon target
LL NN or
RR NN or
or
Pbeam N
ANpC
N NL NR
NL NR
Pbeam Required Accuracy ~5%
Pbeam Required Accuracy ~5%
p C
p C
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the left – right scattering asymmetry AN arises from the interference of
the spin non-flip amplitude with the spin flip amplitude (Schwinger)
in absence of hadronic spin – flip contributions
AN is exactly calculable (Kopeliovich & Lapidus):
hadronic spin- flip modifies the QED“predictions”
interpreted in terms of Pomeron spin – flip and parametrized as
AN for Coulomb -Nuclear Interference.
AN for Coulomb -Nuclear Interference.
)Im()Im( *2
*1
hadflipnon
hadflip
hadflipnon
emflipN CCA
1)p pphad
Z
ty
y
y
m
ZA
pAtot
pAtotp
N 81
1
82
2/3
2
25 2
1
2
1
2
1II ppp
AN (t)
had
p
had
mt
s 05 )(
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Hydrogen Gas Jet and Carbon Wire Targets.
Gas Jet Target Carbon Wire Target
Beam Cross Section
p
FWHM~1.8mmFWHM~1.8mm
Average Pave Peak Ppeak
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The target ladder.
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New target motion mechanism.
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Detector SetupDetector Setup
Ultra thin Carbon ribbon Target(3.5g/cm2)
11
3344
55
66
22
Si strip detectorsSi strip detectors(TOF, E(TOF, ECC))
18cm18cm
10mm10mm
2mm pitch 12 strips2mm pitch 12 strips
72 strips in total72 strips in total
Redundancy
Systematic/Consistency Check
Redundancy
Systematic/Consistency Check
Detector port (inner view)Detector port (inner view)
SSDSSD
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Event Selection
Carbon
400<E<900keV
Very clean Carbon event extraction!
3
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AN at Coulomb Nuclear Interference (CNI) RegionAN at Coulomb Nuclear Interference (CNI) Region
AN C1 flipem *non flip
had C2non flipem * flip
had
pChad
(p 1)
st ? Reggen/Pomeron
exchange
zero hadronic spin-flip
With hadronic spin-flip (E950)
Phys.Rev.Lett.,89,052302(2002)
pC Analyzing Power
Ebeam = 21.7GeVEbeam = 21.7GeV
(High energy & small t limit)
Ebeam = 100 GeVEbeam = 100 GeV
unpublished
Run04
9%
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Polarization measurements in RHIC at 100 GeV.Polarization measurements in RHIC at 100 GeV.
Polarization at 100 GeVin RHIC 60-65%.
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May 3, 2011 A. Poblaguev Spin Meeting
APEX measurements
May 3, 2011 A. Poblaguev Spin Meeting 56
• Many measurements during short period of time• No collisions, rotations, etc.• Different targets in the same fill.
Blue 2Vertical Target 63 measurements
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Polarization profiles, Run 2011
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• Very thin target , practically non-destructive.• Very high rate.• Very good signal/noise ratio. Delayed C-ion
detection.• Single bunch measurements.
• Remaining problems :• Target alignment (Solved).• Carbon strips are not straight. Target lifetime.
P-CNI polarimeter can be an ideal wire-scanner.
P-CNI polarimeter as a wire scanner.
AGS and RHIC CNI polarimeters target mechanisms were upgraded for this Run.
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Yellow, Vertical-15pi, Horiz-13 pi
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AGS pol., during H-jet meas. at injection
Intensity -1.51.13
A AGS ~ A RHIC injection/ 1.11
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Proton polarization measurements in AGS and RHIC at the beam energies 24-250 GeV) are based on Proton-Carbon and Proton-Proton ( H-jet polarimeter) elastic scattering in the Coulomb Nuclear Interference (CNI) region.
The CNI polarimeters are the essential tools for polarized proton acceleration setup and operation and provide polarization values for RHIC experiments.
Polarimeter operation in the scanning mode also gives polarization profile and beam intensity profile (beam emittance) measurements. Bunch by bunch emittance measurements is a very powerful tool for the machine setup.
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AGS polarimeter upgrade andTune-jump system in Run2011.
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RHIC: the “Polarized” Collider
STARPHENIX
AGS, 24GeVLINAC
BOOSTER, 2.5 GeV
Pol. H- ion source
Spin Rotators
20% Snake
Siberian Snakes
200 MeV polarimeter
RHIC pC “CNI” polarimeters
RHIC
Absolute H-jetpolarimeter
Design goal: P=70%, L max = 1.6 1032 s-1cm-2 50 < √s < 500 GeV
AGS pC “CNI” polarimeter
5% Snake
Polarization facilities at RHIC.Polarization facilities at RHIC.
20% snake
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Tune jump system in AGS
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72.7%
Polarization measurement in AGS at 24 GeV.Polarization measurement in AGS at 24 GeV.
Polarization out of AGS60-70%
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Polarization at injection in RHIC with the Jump-Quads in operation.
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16 February 2011 Spin Meeting
AGS CNI Polarimeter 2011
11 February 2011 RHIC Spin Collaboration Meeting 67
1,8 - Hamamatsu, slow preamplifiers
2,3,6,7 - BNL, fast preamplifiers
4,5 - Hamamatsu, fast preamplifiers
3 different detector types:
Run 2009: BNL, slow preamplifiers
Larger length (50 cm)
Regular length (30 cm)
Outer Inner
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AGS Horiz. polarization profile , JQ-off time
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AGS Horiz. polarization profile , JQ-on
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Polarization measurements on the energy ramp in AGS.
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Horizontal emittance, AGS intensity-1.5*10^11
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Vertical emittance, AGS intensity-1.5*10^11
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Absolute H-jet polarimeter in RHIC.
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October 6-10, 2008 A.S. Belov, A. N. Zelenski, SPIN2008, USA
Spin filtering technique. Atomic Beam
Sources. Spin filtering technique. Atomic Beam
Sources. Hydrogen atoms with electron polarization: mJ=+1/2 trajectories.
Electron magnetic moment is 659 times Larger than proton : e / P ~659.Focusing strength: ~ (dB/dr) e
RF transition, polarization transfer from electrons to protons
RHIC beam crossing
Breit-Rabi polarimeter
permanent magnetsextupole - 1.7 Tgradient 5.7 T/cm
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H-jet polarimeter. H-jet polarimeter.
• The H-jet polarimeter includes three major parts: polarized Atomic Beam source (ABS), scattering chamber, and Breit-Rabi polarimeter.
• The polarimeter axis is vertical and the recoil protons are detected in the horizontal plane.
• The common vacuum system is assembled from nine identical vacuum chambers, which provide nine stages of differential pumping.
• The system building block is a cylindrical vacuum chamber 50 cm in diameter and of 32 cm length with the four 20 cm (8.0”) ID pumping ports.
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H-jet dissociator design.H-jet dissociator design.
65 cm
Cooling multifoil copper straps.
Window.
Cold head, 42 K
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Fix RHIC proton beam position (diameter ~1mm).
Move H-Jet-target system for every 1.5 mm step.
Recoil detector can detect H-Jet-target !
Using RHIC-beam and Recoil detector
Using 2.0 mm diameter compression tube
Find the best collision point !
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target
target
beam
beamN PP
tA
RHIC proton
beam
Forward scatteredproton
H-jet target
recoil proton
PPetargt
beametargtbeam
02 inout ppt
beam
beam
target
target
target
target
beam
beam
P
P
P
P
H-Jet polarimeter.
Ptarget is measured by Breit- Rabi Polarimeter
<5%
Elastic scattering: Interference between electromagnetic and hadronic amplitudes in the Coulumb-Nuclear Interference (CNI) region.
2*Im hadNF
emNF
hadSF
hadNF
emSFNA
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RHIC proton beam
H-jet target
IP12
recoil proton
Si detectors (8cm 5cm)3 L-R sides
Strip runs along RHIC beam axis
1ch width = 4mm (400strips)
Channel # relates to recoil angle R, 5 mrad pitch.
Each channel measures kinetic energy TR and TOF.
L = 0.8 m
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Ch#1
source for energy calibration 241Am(5.486 MeV)
How to identify elastic events ?
proton beam
Forward scatteredproton
proton target recoil proton
Array of Si detectors measures TR & ToF of recoil particles. Channel # corresponds to recoil angle R.2 correlations (TR & ToF ) and (TR & R ) the elastic process
Ch#2Ch#3Ch#4Ch#5Ch#6Ch#7Ch#8Ch#9Ch#10Ch#11,12Ch#13Ch#14Ch#15Ch#16Ch#1-16
Ch# R, R big TR big fast protons 02 inout ppt
R
Ch#1
#16
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H-jet is an ideal polarimeter !
• High (~4.5%) analyzing power in a wide energy range (23-250 GeV).
• High event rate due to high intensity (~100 mA) circulated beam current in the storage ring (~6% statistical accuracy in one
8hrs. long fill). High polarized H-jet density in RHIC ABS.• Non-destructive.• No scattering for recoil protons.• Clean elastic scattering event identification.• Straightforward calibration with Breit-Rabi polarimeter.• Most of the false asymmetries are cancelled out in the ratio:
P beam =( 1/A)Beam asym / Target asym
Problem. Polarization dilution by H2, H2O and other residual gases.Largest source of systematic error.
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H-Jet polarimeter: AN in pp
2*Im hadNF
emNF
hadSF
hadNF
emSFNA
24 GeV: calculations with no hadronic spin flip amplitude contribution are not consistent with data
100 GeV: calculations with no hadronic spin flip amplitude contribution are consistent with data
More data to come: 24 GeV: take more data in Run9/1031 GeV: finalize analysis of data from Run6250 GeV: take data in Run9/10
target
target
PA pp
N
24 GeV
100 GeVPLB638, 450
Preliminary
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250 GeV luminescence In H-jet
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Blue vert. IPM measurement-16 pi.
Blue vertical emittance measurement by luminescence monitor in the H-jet polarimeter.
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H-jet polarization measurements, Run 2011
Blue- Blue ringRed- Yellow ring
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Polarization measurements in RHIC with the H-jet polarimeter.
Polarization measurements in RHIC with the H-jet polarimeter.
PTarget
APP
PB
ApC
PB – beam
polarization
Exp.asymm.(pp)
22-250 GeV beam energy.
± 5% absolute accuracy.
Analyzing power measurement
Exp.asymm.(pC)
Measured to ±1% accuracy by the BRP and background evaluation.
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RHIC local polarimeter
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BRAHMS
STARPHENIX
AGSLINAC
BOOSTER
Pol. H- ion source
Spin Rotators
10-20% Snake
Siberian Snakes
200 MeV polarimeter
RHIC pC “CNI” polarimeters
PHOBOS
RHIC
Absolute H-jetpolarimeter
AGS pC “CNI” polarimeter
Polarization facilities at RHIC. “Siberian Snakes”Polarization facilities at RHIC. “Siberian Snakes”
5.9% Snake
E.Courant coined the“Siberian Snake” name
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PHENIX Local Polarimeter
Utilizes spin dependence of very forward neutron production (PLB650, 325):
neutronchargedparticles
ZDC (energy) + SMD (position)
SMDZDC
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PHENIX local polarimeter
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PHENIX Local Polarimeter
Blue Yellow
Blue Yellow
Blue Yellow
Spin Rotators OFFVertical polarization
Spin Rotators ONCorrect Current !Longitudinal polarization!
Spin Rotators ONCurrent ReversedRadial polarization
Asymmetry vs φ
Monitors spin direction in PHENIX collision region
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STAR Local Polarimeter
3.3<||< 5.0 (small tiles only)
Utilizes spin dependence of hadron production at high xF:
Bunch-by-bunch (relative) polarization
Monitors spin direction in STAR collision regionCapable to precisely monitor polarization vs time in a fill, and bunch-by-bunch
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Summary of RHIC polarimetry
Source, Linac, AGS-injector polarimetrs.Hjet:
Absolute polarization measurements Absolute normalization for other RHIC Polarimeters
pC: Separate for blue and yellow beamsNormalization from HJetPolarization vs. time in a fillPolarization profileFill-by-fill polarizations for experiments
PHENIX and STAR Local Polarimeters: Monitor spin direction (through transverse spin component) at collisionPolarization vs time in a fill (for trans. pol. beams)Polarization vs bunch (for trans. pol. beams)