polarized beam in rhic in run 2011. polarimetry at rhic a.zelenski, bnl pstp 2011, september 13,...
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Polarized beam in RHIC in Run 2011.Polarimetry at RHIC
A.Zelenski, BNL
PSTP 2011, September 13, St.Petersburg
RHIC: the “Polarized” Collider
STARPHENIX
AGS, 24GeVLINAC
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.
– Higher polarization out of AGS (jump quads).
– Higher polarization at RHIC store (new working point, tune/orbit feedback on the ramp).
– Highest peak luminosity ~1.6∙1032 cm-2 s-1 in RHIC so far (9MHz, orbit/tune).
– Orbit feedback works. We have excellent orbit control on the ramp.
– 9MHz cavity is operational. No indication of intensity limit.
– 10Hz orbit feedback works. Beneficial to luminosity.– – Chromaticity feedback works for these ramps. Essential for
the down ramp development.
Progress in 2011 polarized proton Run.
Tune jump system in AGS
Polarization at injection in RHIC with the Jump-Quads in operation.
RHIC luminosity in Run-2011
Bunch intensity ~ 1.6 *1011 proton/bunch
Peak luminosity ~1.5*1032 cm2 s
RHIC polarized protons 2000-2011
Wolfram Fischer 7
Run 2011,250 GeV, P-53%
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
Y.Makdisi, A.Poblaguev talks
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.
Proton Lamb-shift polarimeter at3-35keV beam energy. .
Proton Lamb-shift polarimeter at3-35keV beam energy. .
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-)
Layout of the 200 MeV proton polarimeter, (2010)
16.2 deg
Proton-Carbon ElasticScattering at 200 MeV.
Ay=99.96+/0.02%
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.
elastic
GEANT calculation of pC polarimeter for 200MeV proton beam
Collimator Absorber
Sc1 Sc2 Sc3
inelastic
Ep=198.7MeV
Ep=194.3MeV
Measured Analyzing Power vs length of absorber.
Ay(pC) =0.62+/-0.02
16 February 2011 Spin Meeting
AGS CNI Polarimeter 2011
11 February 2011 RHIC Spin Collaboration Meeting 17
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
Polarized proton Recoil carbon
90º in Lab frame
Carbon target
LL NN or
RR NN or
or
A.Poblaguev talk
Three complimentary pillars of the RHIC polarimetry.
p-Carbon CNI polarimeter: relative, fast, polarization profiles, bunch-by bunch measurements, polarization decay time.
Proton-proton H-jet CNI polarimeter: absolute, integral, about 5-7% statistical accuracy in one store.
Local polarimeters: relative, fast, integral, bunch-by-bunch, polarization decay time.
RHIC: the “Polarized” Collider
STARPHENIX
AGS, 24GeVLINAC
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.
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
Beam polarization. Polarization profiles.
• Polarization measurements for accelerator setup and monitoring. Depolarization minimization in AGS and RHIC. Relative (on-line) measurements.
• Polarization loss from intrinsic resonances: polarization lost at edge of beam → polarization profiles.
• Polarization measurements for experimental data normalization (off-line absolute values obtained after detail calibration and normalization). Corrections for polarization profiles.
Hydrogen Gas Jet and Carbon Ribbon Targets.
Gas Jet Target Carbon Ribbon Target
Beam Cross Section
p
FWHM~7 mmFWHM~7 mm
Average Pave Peak Ppeak and averagepolarization
Carbon Ribbon:~ 5-10 µm wide25nm thickness~ 5 µg/cm2
October 6-10, 2008 A.S. Belov, A. N. Zelenski, SPIN2008, USA
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.
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
H-jet, Blue beam, 250 GeV, Run-2011
H-jet, Yellow beam, 250 GeV, Run 2011
October 6-10, 2008 A.S. Belov, A. N. Zelenski, SPIN2008, USA
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.• Direct 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.
H-jet as a luminescence beam intensity monitor.
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
p C
p C
Measurements with p-Carbon CNI polarimeter.
• Polarization, polarization profile measurements in the scanning mode.
• Polarization losses during acceleration and store.• Polarization decay during store.• Beam intensity profile (emttance) including bunch-
by-bunch.• Emittance measurements cross-calibrations.• Emittance measurements on the ramp.
The RHIC p-Carbon CNI polarimeter.
Ultra thin Carbon ribbon Target(5 g/cm2)
11
3344
55
66
22
Si strip detectorsSi strip detectors(TOF, E(TOF, ECC))
18cm18cm
Recoil carbon
Carbon target
LL NN or
Elastic scattering: interference between electromagnetic and hadronic amplitudes in the Coulumb-Nuclear Interference (CNI) region.
RL
RLN
pCN
Nbeam
NN
NN
AP
Ebeam = 100 GeVEbeam = 100 GeV
Run04
The target ladder.
Carbon ribbon~5-10 um wide25 nm thicknes
April 18, 2011, Blue1, H6
Pol. Profile: 250 GeV in Run-2009
R=0.280.07
Intensity and polarization profiles:
P-Carbon polarimeter upgrade for Run-2009
• Two polarimeters in each ring.
• Routine polarization profile measurements in both-vertical and horizontal planes.
• Beam intensity profile (emittance) measurements.
• Doubled number of Carbon-strip targets.
• New detectors development.
Pol. Profile: 250 GeV in Run-2009
• Polarization loss from intrinsic resonances: polarization lost at edge of beam → polarization profile.
• Impact of polarization profile on beam polarization at collisions:
For RH ≈ RV and small: P0 = <P> (1+<R>)2;
Pcoll. = <P> (1+½<R>)
There is a
Polarization evolution in AGS and RHIC.
Note that P0, the polarization of the core particle, should be equal to the maximum achievable polarization.
<P> <R> Pcoll. P0 Pmax.
AGS extr. 67.6 ± 1.0 0.02 ± 0.02
70.3 ± 1.0 80.0
RHIC inj., B 65.7 ± 0.3 0.08 ± 0.02
76.6 ± 0.4 76.6
RHIC inj., Y 66.3 ± 0.3 0.08 ± 0.02
77.3 ± 0.4 79.3
RHIC 250 GeV, B 52.2 ± 0.3 0.17 ± 0.02
56.6 ± 0.3 71.5 ± 0.4 76.6
RHIC 250 GeV, Y 54.5 ± 0.3 0.16 ± 0.02
58.9 ± 0.3 73.3 ± 0.4 79.3
There is a possibility of an additional longitudinal polarization profile.
Polarization profiles Run 9, Injection
Polarization profiles at 100GeV, Run 2009
Polarization profiles at 250GeV, Run 2009
Run-2009, polarization profiles.
May 3, 2011 A. Poblaguev Spin Meeting
Polarization profiles at injection, Run-2011
May 3, 2011 A. Poblaguev Spin Meeting
24 GeV, Blue-2, Horiz profiles, Run-2011
May 3, 2011 A. Poblaguev Spin Meeting
24 Gev, Blue-1, Horiz target, Vert profiles
May 3, 2011 A. Poblaguev Spin Meeting
Run-2011, 250 GeV, Blue-2, Horiz profiles
May 3, 2011 A. Poblaguev Spin Meeting
Run-2011,250 GeV, Yellow-1, Vert.profiles
May 3, 2011 A. Poblaguev Spin Meeting
Polarizaion profiles in Run-2011
Polarization decay during the store.Yellow ring, Vert.target, 0.72+/-
0.18%/hr
Blue-1, 250 GeV, Run-2011
Blue-2,Vertical target, 250 GeV
Yellow-2, 250 GeV, Run-2011
P-Carbon /H-jet for different targets.
Ribbon target orientation.
Target strip orientation
Yellow, Vertical-15pi, Horiz-13 pi
Summary of RHIC polarimetry
Source, Linac, AGS-injector polarimetrs.Absolute H-jet polarimeter:
Absolute polarization measurements Absolute normalization for other RHIC Polarimeters
Proton-Carbon polarimeters: Separate for blue and yellow beamsNormalization from H-JetPolarization vs. time in a fillPolarization profilesFill-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)
Summary
AGS horizontal tune jump system operational: P +5% with high intensity.Acceleration near Qv = ⅔ in RHIC: P +25%
Polarization at end of 250 GeV ramp: 53 %With incremental improvements <P> = 55 - 60% possible for next run:Changes in source/LEBT/MEBT: + 6% in <P>Smaller emittance growth (24 → 18 p mm): + 8% in <P> Small change in store energy: no P decay during store: + 5% in <P>.Vertical/horizontal beam motion decoupling.