Rhic polarized Proton Operation M. Bai, c-a dept, bnl outline rhic polarized proton set-up

RHIC Polarized Proton Operation M. Bai, C-A Dept, BNL

• Outline

• RHIC polarized proton set-up

• RHIC polarized proton performance

• plan for RHIC polarized proton

• summery

Spin dynamics in a circular accelerator

Challenge of Accelerating Polarized Beams

RHIC Complex Layout

Booster Polarized Proton Setup

AGS Polarized Proton Setup

RHIC polarized proton setup

Depolarizing mechanism in the presence of snakes

RHIC pp acceleration strategy

RHIC pp acceleration setup

RHIC overall performance

RHIC luminosity performance

RHIC polarization performance

RHIC polarization transmission efficiency

250 GeV Development

250 GeV polarization ramp measurement

Possible reason for polarization loss

Remaining issues

• Luminosity:

• Limited by beam-beam effect

• Polarization

• Polarization loss in the AGS due to horizontal spin resonances
• Polarization intensity dependence from AGS
• Polarization loss in RHIC between 100 GeV and 250 GeV

Plan for FY2009

• Luminosity: 23x1030 —>40x1030[cm-2s-1]

• 9MHz cavity: shorter bunch length
• Improve the longitudinal matching
• Allow longer bunch length during acceleration to minimize the electron cloud
• Non-linear chromaticity correction
• Increase the effective tune space to accommodate larger beam-beam effect, i.e. higher bunch intensity
• Beta squeeze
• A further beta squeeze from 1m to 0.7m gives an increase of luminosity of 40%

Plan for FY2009

• Polarization

• Control the spin tune
• Control the orbital angle between snakes
• calibrate the snake current error on spin tune as function of energy
• Optics control along the ramp to avoid snake resonances
• RHIC tune/decoupling feedback
• AGS improvement
• Fast quad to jump across H resonances to minimize the polarization losses
• Minimize beam emittance
• LEBT/MEBT upgrade
• Better optics matching between Booster to AGS

Conclusion

• RHIC has achieved 60% polarization at 100 GeV and 45% at 250 GeV

• Expect to achieve 100% polarization transmission to 250GeV with better orbital and optics control

• AGS plans on increase the polarization transmission efficiency and mitigate the polarization dependence on bunch intensity

• Various efforts in RHIC aiming to improve the luminosity to 40x1030[cm-2s-1] for Run 2009

Backup slides

RHIC 100 GeV Ramp