Polarized beam in RHIC in Run 2011.Polarimetry at RHICA.Zelenski, BNLPSTP 2011, September 13, St.Petersburg

RHIC: the Polarized Collider STARPHENIX AGS, 24GeVLINACPol. H- ion sourceSpin Rotators20% SnakeSiberian Snakes200 MeV polarimeterRHIC pC CNI polarimetersRHICAbsolute H-jetpolarimeterDesign goal - 70% Polarization L max = 1.6 1032 s-1cm-2 50 < s < 500 GeVAGS pC CNI polarimeter5% SnakePolarization 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 ~1.61032 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-2011Bunch intensity ~ 1.6 *1011 proton/bunchPeak luminosity ~1.5*1032 cm2 s

RHIC polarized protons 2000-2011Wolfram Fischer*

Run 2011,250 GeV, P-53%

Polarimetry at RHICFaraday rotation polarimeterLamb-shift polarimeter200 MeV - absolute polarimeterAGS p-Carbon CNI polarimeterRHIC p-Carbon CNI polarimeterRHIC - absolute H-jet polarimeterLocal polarimeters at STAR and PHENIX

Y.Makdisi, A.Poblaguev talks

Faraday rotation polarimeter of Rb vapor.p-optical pumping on.0-optical pumping -off.PD1PD1=I0 sin pPD2=I0 cos p

PRb= (p- 0)/ 0PD2Cr:LISAF pumping laser at795 nmRb-cell/2Linear polarized probe laser beam at 780 nm.

Proton Lamb-shift polarimeter at3-35keV beam energy. .H- H+ H(2S)B=575 GLa(10.2eV) -121.6 nmH(2S)N+ =N0(1+P) / 2N- = N0(1-P) / 2P=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%

Detector and variable absorber setupfor 200 MeV proton beam.

elasticGEANT calculation of pC polarimeter for 200MeV proton beaminelasticEp=198.7MeVEp=194.3MeV

Measured Analyzing Power vs length of absorber.Ay(pC) =0.62+/-0.02

AGS CNI Polarimeter 201111 February 2011RHIC Spin Collaboration Meeting*1,8 - Hamamatsu, slow preamplifiers2,3,6,7 - BNL, fast preamplifiers4,5 - Hamamatsu, fast preamplifiers3 different detector types:Run 2009: BNL, slow preamplifiersLarger length (50 cm)Regular length (30 cm)OuterInnerA.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 ColliderSTARPHENIX AGS, 24GeVLINACPol. H- ion sourceSpin Rotators20% SnakeSiberian Snakes200 MeV polarimeterRHIC pC CNI polarimetersRHICAbsolute H-jetpolarimeterDesign goal - 70% Polarization L max = 1.6 1032 s-1cm-2 50 < s < 500 GeVAGS pC CNI polarimeter5% SnakePolarization facilities at RHIC.

PHENIX Local PolarimeterSpin Rotators OFFVertical polarizationSpin Rotators ONCorrect Current !Longitudinal polarization!Spin Rotators ONCurrent ReversedRadial polarizationAsymmetry vs 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 TargetCarbon Ribbon TargetBeam Cross SectionFWHM~7 mmAverage PavePeak Ppeak and averagepolarizationCarbon Ribbon:~ 5-10 m wide25nm thickness~ 5 g/cm2

RHIC proton beamForward scatteredproton H-jet target recoil protonH-Jet polarimeter. Ptarget is measured by Breit- Rabi Polarimeter

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 protonsRHIC beam crossingBreit-Rabi polarimeter

H-jet, Blue beam, 250 GeV, Run-2011

H-jet, Yellow beam, 250 GeV, Run 2011

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 RHIC

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 mg/cm2)Si strip detectors(TOF, EC)18cmRecoil carbonCarbon targetElastic scattering: interference between electromagnetic and hadronic amplitudes in the Coulumb-Nuclear Interference (CNI) region.

The target ladder.Carbon ribbon~5-10 um wide25 nm thicknes

April 18, 2011, Blue1, H6

Pol. Profile: 250 GeV in Run-2009

P-Carbon polarimeter upgrade for Run-2009Two 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-2009Polarization 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 = (1+)2; Pcoll. = (1+)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.There is a possibility of an additional longitudinal polarization profile.

Pcoll.P0Pmax.AGS extr.67.6 1.00.02 0.0270.3 1.080.0RHIC inj., B65.7 0.30.08 0.0276.6 0.476.6RHIC inj., Y66.3 0.30.08 0.0277.3 0.479.3RHIC 250 GeV, B52.2 0.30.17 0.0256.6 0.371.5 0.476.6RHIC 250 GeV, Y54.5 0.30.16 0.0258.9 0.373.3 0.479.3

Polarization profiles Run 9, Injection

Polarization profiles at 100GeV, Run 2009

Polarization profiles at 250GeV, Run 2009

Run-2009, polarization profiles.

Polarization profiles at injection, Run-2011

24 GeV, Blue-2, Horiz profiles, Run-2011

24 Gev, Blue-1, Horiz target, Vert profiles

Run-2011, 250 GeV, Blue-2, Horiz profiles

Run-2011,250 GeV, Yellow-1, Vert.profiles

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 PolarimetersProton-Carbon polarimeters: Separate for blue and yellow beamsNormalization from H-JetPolarization vs. time in a fillPolarization profilesFill-by-fill polarizations for experimentsPHENIX 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)

SummaryAGS horizontal tune jump system operational: P +5% with high intensity.Acceleration near Qv = in RHIC: P +25%Polarization at end of 250 GeV ramp: 53 %With incremental improvements = 55 - 60% possible for next run:Changes in source/LEBT/MEBT: + 6% in Smaller emittance growth (24 18 p mm): + 8% in Small change in store energy: no P decay during store: + 5% in .Vertical/horizontal beam motion decoupling.

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