Polarization Measurement of 100GeV Proton Beams at RHIC

with CNI pC Polarimeter

Polarization Measurement of 100GeV Proton Beams at RHIC

with CNI pC Polarimeter

Itaru Nakagawa (RIKEN/RBRC)Itaru Nakagawa (RIKEN/RBRC)On behalf of CNI Polarimeter GroupOn behalf of CNI Polarimeter GroupI.G.AlekseevI.G.AlekseevA A A.BravarA.BravarB B G.BunceG.BunceB B S.DhawanS.DhawanDD R.Gill R.GillBB H.Huang H.HuangB B W.HaeberliW.HaeberliE E G.Igo G.IgoFF O.Jinnouchi V.P.Kanavets O.Jinnouchi V.P.KanavetsAA K.Kurita K.KuritaHH A.Khodinov A.KhodinovJ J Z.Li Z.LiB B Y.Makdi Y.MakdisisiBB A.Nass A.NassBB W.Lozowski W.LozowskiII W.W.MacKay W.W.MacKayBB H.Okada H.OkadaGG S.Rescia S.ResciaBB T.Roser T.RoserBB N. N. SaitoSaitoG G H.Spinka H.SpinkaL L D.N.SviridaD.N.SviridaAA D.Underwood D.UnderwoodL L C.Witten C.WittenFF T.Wise T.WiseII J.Wood J.WoodF F A.A.ZelenskiZelenskiBB

RBRC ITEPRBRC ITEPAA BNL BNLBB ANL ANLCC Yale U Yale UDD Wisconsin U Wisconsin UEE UCLA UCLAFF Kyoto UKyoto UG G Rikkyo URikkyo UH H Indiana UIndiana UII StonyBrook U StonyBrook UJJ IUCF IUCFK K Argonne UArgonne ULL

Itaru Nakagawa (RIKEN/RBRC)Itaru Nakagawa (RIKEN/RBRC)On behalf of CNI Polarimeter GroupOn behalf of CNI Polarimeter GroupI.G.AlekseevI.G.AlekseevA A A.BravarA.BravarB B G.BunceG.BunceB B S.DhawanS.DhawanDD R.Gill R.GillBB H.Huang H.HuangB B W.HaeberliW.HaeberliE E G.Igo G.IgoFF O.Jinnouchi V.P.Kanavets O.Jinnouchi V.P.KanavetsAA K.Kurita K.KuritaHH A.Khodinov A.KhodinovJ J Z.Li Z.LiB B Y.Makdi Y.MakdisisiBB A.Nass A.NassBB W.Lozowski W.LozowskiII W.W.MacKay W.W.MacKayBB H.Okada H.OkadaGG S.Rescia S.ResciaBB T.Roser T.RoserBB N. N. SaitoSaitoG G H.Spinka H.SpinkaL L D.N.SviridaD.N.SviridaAA D.Underwood D.UnderwoodL L C.Witten C.WittenFF T.Wise T.WiseII J.Wood J.WoodF F A.A.ZelenskiZelenskiBB

RBRC ITEPRBRC ITEPAA BNL BNLBB ANL ANLCC Yale U Yale UDD Wisconsin U Wisconsin UEE UCLA UCLAFF Kyoto UKyoto UG G Rikkyo URikkyo UH H Indiana UIndiana UII StonyBrook U StonyBrook UJJ IUCF IUCFK K Argonne UArgonne ULL

Polarimetry: Impact on RHIC-SPINPolarimetry: Impact on RHIC-SPIN

€

ALL =1

Pbeam2

N↑↑ − N↑↓

N↑↑ + N↑↓

⎛

⎝ ⎜ ⎜

⎞

⎠ ⎟ ⎟ ⇒ ΔG

€

AN =1

Pbeam

N↑ − N↓

N↑ + N↓

⎛

⎝ ⎜ ⎜

⎞

⎠ ⎟ ⎟

Physics AsymmetriesSingle Spin Asymmetries

Double Spin Asymmetries

Polarization measurement by Elastic pp/pC

Polarized proton Recoil carbon

90º in Lab frame

Carbon target

↓↑LL NN or

↓↑RR NN or

↓↑or

€

Pbeam = −εN

ANpC

εN =NL − NR

NL + NR

Pbeam Required Accuracy ~5%

Pbeam Required Accuracy ~5%

€

rp p( p

r p ) /

r p C

AN at Coulomb Nuclear Interference (CNI) RegionAN at Coulomb Nuclear Interference (CNI) Region

€

AN ≈ C1φ flipem *

φnon− fliphad + C2φnon− flip

em *φ flip

had

€

∝ σ pChad

€

∝ (μ p −1)

€

∝αst ? Pomeron exchange

zero hadronic spin-flip

With hadronic spin-flip (E950)

Phys.Rev.Lett.,89,052302(2002)

pC Analyzing Power

€

ANpC =

1

Pbeam

εN Requires absolute calibration

p = 21.7GeV Need to measure ANpC @ 100GeV

€

ANbeam (t) = −AN

target (t)

Pbeam = −Ptarget

εbeam

ε target

€

rp beam

€

rp target

Elastic pp

(High energy & small t limit)

Characteristics of pC polarimeterCharacteristics of pC polarimeter

• Large Cross Section

• Solid target

• 20 sec./measurement with (sta) ~ 2%

• Immediate feedback to accelerator operation

• “Fill by Fill” & “Bunch by Bunch” measurement

• Polarization profile measurement

• ANpC ~ a few %

High Event Rate

RHIC PolarimetryRHIC Polarimetry

BRAHMS & PP2PP (p)

STAR (p)PHENIX (p)

AGS

LINAC BOOSTER

Pol. Proton Source500 A, 300 s

Spin RotatorsSolenoid Snake

Siberian Snakes

200 MeV Polarimeter

AGS pC CNI PolarimeterAC Dipole

RHIC pC Polarimeters

Absolute Polarimeter (H jet)

RHIC

Siberian Snakes

Cold Snake

Warm Snake

pC Detector SetuppC Detector SetupUltra thin Carbon ribbon Target(3.5 g/cm2)

11

3344

55

66

22

Si strip detectorsSi strip detectors(TOF, E(TOF, ECC))

15cm15cm

10mm10mm

2mm pitch 12 strips2mm pitch 12 strips

pp++ implants implants~150 nm depth~150 nm depth

72 strips in total72 strips in total

Thin dead layer for low energy Thin dead layer for low energy carbon spectroscopy carbon spectroscopy

~100mV

BunchBunch

Ne

xt

Bu

nc

hN

ex

t B

un

ch

(60

bu

nc

h m

od

e)

(60

bu

nc

h m

od

e)

Shaped Si Signal

Ne

xt

Bu

nc

hN

ex

t B

un

ch

(12

0 b

un

ch

mo

de

)(1

20

bu

nc

h m

od

e)

Wave Form Digitizer (WFD)Wave Form Digitizer (WFD)420 Msamples/sec

- Pulse Height - Bunch ID- TOF - Integral (Q)- TMAX - revolution #

Select carbons at on-board LUTSelect carbons at on-board LUT Scaler dataScaler data Asymmetry calculationAsymmetry calculation Online results (to experiments)Online results (to experiments)

Event by event dataEvent by event data Stored in on-board memoryStored in on-board memory Used for offline detailed studyUsed for offline detailed study

offline

online

Redundancy

Systematic/Consistency Check

Event SelectionEvent Selection

+3σ

-3σ

12C

α

Run4

Run5

Run05 Online ResultsRun05 Online Results

PHENIXPhysics Store

Fill Number Fill Number

Pol

ariz

atio

n [%

]

Pol

ariz

atio

n [%

]P

olar

izat

ion

[%]

Run5 Polarization Profile Run5 Polarization Profile

2mm

2mm

Pol

ariz

atio

nC

ount

Rat

e[H

z]

Cou

nt R

ate[

Hz]

pC extended t-range AN @ 100GeVpC extended t-range AN @ 100GeV

No Hadronic Spin flip

Best Fit with Hadronic Spin-fliphep-ph/0305085

€

ANpC =

1

Pbeam

εN

From Run4 pp

ANpC@100GeV will soon be finalized

> 0.1(GeV/c)2

Run5

Data from Run4

Preliminary

SummarySummary

• RHIC Beam Polarization was measured by taking

asymmetry of pC elastic scattering.

• Absolute calibration was done using Pbeam determin

ed by elastic pp scattering data(Run4).

• ANpC was measured for extended t range (Up to t>

0.1 (GeV/c)2 )to explore t-evolution of hadronic spi

n-flip amplitude.

• RHIC Beam Polarization was measured by taking

asymmetry of pC elastic scattering.

• Absolute calibration was done using Pbeam determin

ed by elastic pp scattering data(Run4).

• ANpC was measured for extended t range (Up to t>

0.1 (GeV/c)2 )to explore t-evolution of hadronic spi

n-flip amplitude.

€

rp

r p