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

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.