Polarized beam in RHIC in Run Polarimetry at RHIC A.Zelenski, BNL PSTP 2011, September 13, St.Petersburg

RHIC: the “Polarized” Collider STAR PHENIX AGS, 24GeV LINAC Pol. H - ion source Spin Rotators 20% Snake Siberian Snakes 200 MeV polarimeter RHIC pC “CNI” polarimeters RHIC Absolute H-jet polarimeter Design goal - 70% Polarization L max = 1.6  s -1 cm < √s < 500 GeV AGS pC “CNI” polarimeter 5% Snake 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∙10 32 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 *10 11 proton/bunch Peak luminosity ~1.5*10 32 cm 2 s

RHIC polarized protons Wolfram Fischer7 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. Θp-optical pumping –on. Θ 0 -optical pumping -off. PD1 PD 1 =I 0 sin θ p PD 2 =I 0 cos θ p P Rb = ( θ p - θ 0 )/  θ 0 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.. H - → H + → H(2S) B=575 G La(10.2eV) nm H(2S) N + =N 0 (1+P) / 2 N - = N 0 (1-P) / 2 P=2 (N + -N - )/(N + +N - )

Layout of the 200 MeV proton polarimeter, (2010) 16.2 deg

Proton-Carbon Elastic Scattering at 200 MeV.

A y =99.96+/0.02%

Detector and variable absorber setup for 200 MeV proton beam.

elastic GEANT calculation of pC polarimeter for 200MeV proton beam inelastic E p =198.7MeV E p =194.3MeV

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

16 February 2011Spin Meeting AGS CNI Polarimeter February 2011RHIC Spin Collaboration Meeting17 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 ) OuterInner Polarized proton Recoil carbon 90º in Lab frame Carbon target 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 STAR PHENIX AGS, 24GeV LINAC Pol. H - ion source Spin Rotators 20% Snake Siberian Snakes 200 MeV polarimeter RHIC pC “CNI” polarimeters RHIC Absolute H-jet polarimeter Design goal - 70% Polarization L max = 1.6  s -1 cm < √s < 500 GeV AGS pC “CNI” polarimeter 5% Snake Polarization facilities at RHIC.

PHENIX Local Polarimeter BlueYellow BlueYellow BlueYellow Spin Rotators OFF Vertical polarization Spin Rotators ON Correct Current ! Longitudinal polarization! Spin Rotators ON Current Reversed Radial 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  FWHM~7 mm Average P ave Peak P peak and average polarization Carbon Ribbon: ~ 5-10 µm wide 25nm thickness ~ 5 µg/cm 2

October 6-10, 2008 A.S. Belov, A. N. Zelenski, SPIN2008, USA RHIC proton beam Forward scattered proton H-jet target recoil proton H-Jet polarimeter. P target 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. Hydrogen atoms with electron polarization: m J =+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 magnet sextupole T gradient 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 ( 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 H 2, H 2 O and other residual gases. Largest source of systematic error.

H-jet as a luminescence beam intensity monitor.

p-Carbon Polarimetry at RHIC Polarized proton Recoil carbon 90º in Lab frame Carbon target

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/cm 2 ) Si strip detectors (TOF, E C ) 18cm Recoil carbon Carbon target Elastic scattering: interference between electromagnetic and hadronic amplitudes in the Coulumb-Nuclear Interference (CNI) region. E beam = 100 GeV Run04

The target ladder. Carbon ribbon ~5-10 um wide 25 nm thicknes

April 18, 2011, Blue1, H6

Pol. Profile: 250 GeV in Run-2009 R=0.28  0.07 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: P 0 = (1+ ) 2 ; P coll. = (1+½ ) There is a

Polarization evolution in AGS and RHIC. Note that P 0, the polarization of the core particle, should be equal to the maximum achievable polarization. P coll. P0P0 P max. AGS extr.67.6 ± ± ± RHIC inj., B65.7 ± ± ± RHIC inj., Y66.3 ± ± ± RHIC 250 GeV, B52.2 ± ± ± ± RHIC 250 GeV, Y54.5 ± ± ± ± 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, 2011A. Poblaguev Spin Meeting Polarization profiles at injection, Run-2011

May 3, 2011A. Poblaguev Spin Meeting 24 GeV, Blue-2, Horiz profiles, Run-2011

May 3, 2011A. Poblaguev Spin Meeting 24 Gev, Blue-1, Horiz target, Vert profiles

May 3, 2011A. Poblaguev Spin Meeting Run-2011, 250 GeV, Blue-2, Horiz profiles

May 3, 2011A. Poblaguev Spin Meeting Run-2011,250 GeV, Yellow-1, Vert.profiles

May 3, 2011A. 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 beams Normalization from H-Jet Polarization vs. time in a fill Polarization profiles Fill-by-fill polarizations for experiments PHENIX and STAR Local Polarimeters: Monitor spin direction (through transverse spin component) at collision Polarization 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 Q v = ⅔ in RHIC: P +25% Polarization at end of 250 GeV ramp: 53 % With incremental improvements = % 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.