RHIC Polarized Proton Operations - PowerPoint Presentation

Slide1

RHIC Polarized Proton Operations

Mei BaiGSI Helmholtzzentrum für Schwerionenforschung

Slide2

RHIC, the world’s 1

st high energy pp colliderhttps://www.agsrhichome.bnl.gov/RHIC/Runs/

Slide3

94 PRL

Slide4

PHENIX (p)

AGS

LINAC

BOOSTER

Pol. H

-

Source

200 MeV Polarimeter

Helical Partial

Siberian Snake

Spin Rotators

(longitudinal polarization)

Siberian Snakes

Spin Rotators

(longitudinal polarization)

Strong AGS Snake

RHIC pC Polarimeters

Absolute Polarimeter (H jet)

STAR (p)

BRAHMS(p)

AGS Polarimeters

SpinFest, August 7, 2008

4

Slide5

Snake Depolarization Resonance

Condition

even order resonance

Disappears in the two snake case if the closed orbit is perfect

odd order resonance

Driven by the intrinsic spin resonances

3/4

7/10

11/16

old working point

current working point

Py

S. Y. Lee, Tepikian, Phys. Rev. Lett. 56 (1986) 1635

S. R. Mane, NIM in Phys. Res. A. 587 (2008) 188-212

Slide6

How to avoid a snake resonance?

Keep spin tune as close to 0.5 as possible

Snake current setting

Minimize horizontal orbital angle between two snakes

Precise control of the vertical closed orbit

Precise optics control

Proper working point at a location with no or negligible snake resonances

Minimize the linear coupling to avoid the resonance due to horizontal

betatron

oscillation

Minimize spin tune spread

Slide7

RHIC Polarization Performance

pp@100 GeVpp@205GeVpp@250GeV

pp@255GeV

Commissioning of OPPIS, snakes, rotators

Operation modes developments

Improvement of injectors, beam controls and polarimeters

Slide8

Milestones of RHIC pp

Developement2000

New polarized proton source (OPPIS) commissioned

One snake was installed in Blue ring and commissioned

CNI

polarimeter

in Blue installed and commissioned

2002

All snakes for both rings installed and commissioned

CNI

polarimeter

in Yellow installed and commissioned

2003

Spin rotators installed and commissioned

2004

RHIC absolute

polarimeter

using H Jet target installed and commissioned

AGS 5% helical warm snake installed and commissioned

RHIC polarized proton to 100 GeV engineering run

Slide9

June 7, 2004

RHIC Retreat 2004

RHIC pp Engineering Run in 2004

A brief history of Run04

Goal of the run

Slide10

June 7, 2004

RHIC Retreat 2004

Snake Current Scans

blue snakes and yellow snakes do behave differently

inner current: blue=323A; yellow=321A

outer current: blue=105A; yellow=97A

the snake current is very critical to get spin tune close to 1/2

through out the run, the snake current was set to

inner current=(

326A

,

321A

); outer current=(

100A

,

100A

)

Slide11

June 7, 2004

RHIC Retreat 2004

RHIC

New Working Point

good spot for

polarization as

well as for beam

lifetime

a snake depolarization

resonance

Loss rate

Courtesy of R. Tomas

Working point

during ramp

good for

Beam lifetime,

but bad for

polarization

Slide12

June 7, 2004

RHIC Retreat 2004

Tunes along the ramp

Time from the beginning of the ramp [s]

flattop



*=2m



*=1m

Measured betatron tune

Yellow tunes

Blue tunes

No beam loss while crossing

7

th

order resonance at 0.717

Other than the desired tune

swing from (0.72,0.73) to

(0.68,0.69), No significant

tunes variations along the ramp

Slide13

June 7, 2004

RHIC Retreat 2004

Tune feed forward

Before tune

“

ironing

”

after tune

“

ironing

”

Slide14

June 7, 2004

RHIC Retreat 2004

Tune feedback

Slide15

Milestones of RHIC pp

Developement2004

RHIC absolute

polarimeter

using H Jet target installed and commissioned

AGS 5% helical warm snake installed and commissioned

RHIC polarized proton to 100 GeV engineering run

2005

New super-conducting solenoid was installed in the OPPIS source

Polarized protons in RHIC to 205 GeV with ~ 30% polarization at top energy

AGS strong super-conducting helical snake installed and commissioned

Slide16

Polarized proton collision at 205 GeV at RHIC

Slide17

Milestones of RHIC pp

Developement2005

New super-conducting solenoid was installed in the OPPIS source

Polarized protons in RHIC to 205 GeV with ~ 30% polarization at top energy

AGS strong super-conducting helical snake installed and commissioned

2006

commissioned the AGS dual snake configuration. AGS reaches a polarization

of 65% at the AGS extraction with 1.5x10

11

protons per bunch

Polarized protons were accelerated to 250 GeV with a polarization of 45%

2009

1

st

Physics run of polarized protons at 250 GeV. discovered the strong snake resonance at 5Qy=Qs+1

polarization

deteoration

at a rate of ~1%/hour was observed at both 100GeV as well as 250GeV

2011

first polarized proton run with full tune/coupling feedback. The improvement Long physics run of polarized protons at 255 GeV with vertical

9MHz cavity successfully commissioned

Slide18

Polarization Performance: 250 GeV

Polarization loss between 100 GeV and 250 GeV

Measured with CNI polarimeter

Slide19

Snake resonance observed in RHIC

7/10 resonance

11/16 resonance

3/4 resonance

Setting for 2009 250 GeV run

Setting for 2011 250 GeV run

Slide20

Milestones of RHIC pp Developement

2006

commissioned the AGS dual snake configuration. AGS reaches a polarization

of 65% at the AGS extraction with 1.5x10

11

protons per bunch

Polarized protons were accelerated to 250 GeV with a polarization of 45%

2012

polarized proton run at both 255GeV and 100GeV

AGS H tune jump technique was successfully commissioned and became operational

9MHz cavity became operational

2013

polarized proton run at 255GeV

Blue

elens

was installed and started its commissioning

OPPIS upgrade with fast atomic beam source and improved superconducting solenoid

longitudinal bunch-by-bunch damper was successfully commissioned

improved AGS H tune jump timing

Slide21

Accelerating pp in the AGS with dual partial snakes

Energy: 2.3 GeV ~ 23.8 GeV

A total of 41 imperfection resonances and 7 intrinsic resonances from injection to extraction

A20

10~15%

E20

5.9%

Slide22

Spin tune with two partial snakes

Courtesy of T. Roser

Spin tune

Extraction

36+

Q

y

intrinsic resonance

G

g

Vertical betatron tune

Vertical component

of stable spin

Slide23

Horizontal Resonance

Stable spin direction in the presence of two partial snakes is no long along vertical direction

vertical fields due to horizontal betatron oscillation can drive a resonance at

G



= kP±Qx

Each is weak, and can be cured by tune jump

Courtesy of Yann Dutheil

Tracking of 6k particles in 6-D Gaussian distribution(10π mm-mrad + 0.8ev-s)

Total CPU hour=10,000

done by Yann using zgoubi[1]

Slide24

AGS Horizontal Tune Jump Quads

AGS horizontal tune jump quadrupoles to overcome a total of 80 weak horizontal spin resonances during the acceleration

Spin tune

Qx

1 - Qx

[1] V. Schoefer

et al,

INCREASINGTHEAGSBEAMPOLARIZATIONWITH80TUNEJUMPS,

Proceedings of IPAC2012, New Orleans, Louisiana, USA

[2]

F. Lin, et al., Phys. Rev. ST 10, 044001 (2007)

IPAC

’

13, Shanghai, China, May 12-May 17, 2013

M. Bai

Slide25

Precise Beam Control

Tune/coupling feedback system: acceleration close to 2/3 orbital resonance

Orbit feedback system: rms orbit distortion less than 0.1mm

Slide26

The Golden Store of RUN 13

Improved longitudinal matching at RHIC injection led smaller beam emittance. Together with improved 3

rd

order resonance correction of store lattice improved polarization lifetime significantly

Slide27

Summary

The success of RHIC polarized proton operation is the result of original scientific vision and excellent team work!The original RHIC spin collaboration who initiated RHIC spin programThe strong support of the funding agencies, BNL, DOE, RIKEN, etcThe accelerator team who designed, constructed, commissioned the collider!Fantastic coordination among accelerator folks and experimental folksDonuts and cookies helped a bit deal!

The success of the RHIC spin program will soon lead us to the next excitement with Electron Ion Collider that can allow us to continue the passion for spin physics that Jacques

Soffer

and other spin physicists and further understand the glues that bind us together!

Slide28

An Incredible Team

L. Ahrens, E.C. Aschenauer, G. AtoianJ. Beebe-Wang, M. Blaskiewicz J.M. Brennan, K. Brown, D. Bruno, R. Connolly, K.O. EyserT. D’Ottavio, K.A. Drees, Y. Dutheil, W. FischerC. Gardner, J.W. Glenn, X. Gu, M. Harvey, T. Hayes, H. Huang, R. Hulsart, A. KirleisJ. Laster, C. Liu, Y. Luo, Y. Makdisi G. MarrA. Marusic, F. Meot, K. Mernick, R. Michnoff, M. Minty, C. Montag, J. Morris, S. Nemesure , P. Pile, A. Poblaguev, V. Ptitsyn, V. H. RanjbarG. Robert-Demolaize, T. Roser,W. Schmidke, V. Schoefer, F. Severino, T. C. Shrey, D. Smirnov, K. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, J. Tuozzolo G. Wang, M. Wilinski, S. White, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang