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Polarized Protons in RHIC at 500 GeV

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Need a factor of 3 to achieve the design luminosity goal. Current luminosity limit ... Gradient error correction is also under development by Todd, Jen and Mei during ... – PowerPoint PPT presentation

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Title: Polarized Protons in RHIC at 500 GeV


1
Polarized Protons in RHIC at 500 GeV
  • Mei Bai
  • C-A Dept. BNL

2
RHIC pp design parameter
Achieved performance for Physics Runs
3
Luminosity performance
  • Need a factor of 3 to achieve the design
    luminosity goal
  • Current luminosity limit
  • Beam-beam interaction
  • Cause emittance growth through non-linear
    resonance and other effects.
  • Current pp workpoint at (0.695,0.685) hits the
    limit by 3Qx resonance and 10Qx,y
  • E-cloud possibly an additional source of
    emittance growth

4
Polarization performance
  • Achieved 100 polarization transmission
    efficiency from injection to 100 GeV
  • Much stronger spin depolarzing resonances from
    100 GeV to 250 GeV

5
RHIC intrinsic spin resonance spectrum

Design goal
Achieved Physics Run
Intrinsic spin resonance Qx28.73, Qy29.72,
emit 10
6
FY 2006 RHIC pp 250 GeV development(one week)
  • Explore polarization transmission to a beam
    energy of 250 GeV
  • Inspect the luminosity aspects (witn 2
    collisions)
  • Store lifetime
  • Total intensity limits
  • Power supply preparations 2 shifts
  • Ramp and polarization development 8 shifts
  • Dedicated polarization studies 2 shifts
  • Dedicated luminosity studies 2 shifts
  • Contingency shifts 2.5 shifts
  • Total required 16.5 shifts or ( 5 days 1.5
    shifts)

7
Overview of RHIC pp 250 GeV development
Yellow ps lead flow problem
Fix the rf ring to ring synchro
Booster problem, ps problem
Ps problem, access control problem
Weather related down time
ps problem, access control problem
Quench recovery
ps work
Booster problem
Booster problem
8
What have been achieved?
  • Blue beam was first accelerated up to 250 GeV at
    the end of FY2006 pp RUN

9
pp in blue accelerated to 250 GeV with 45
polarization
250 GeV
injection
Polarization at 250 GeV
Polarization at injection
10
What have been achieved?
  • Blue beam was first accelerated up to 250 GeV at
    the end of FY2006 pp RUN
  • Polarization measurement as a function of beam
    energy identifies the location of polarization
    loss

11
RHIC pp polarization ramp measurement

12
Remaining issues of RHIC pp 250 GeV development
  • Exam the polarization transmission efficiency in
    Yellow
  • Systematic study of polarization along the energy
    ramp as function of orbit distortion and beam
    tunes at depolarization resonances beyond 100 GeV
  • Establish collisions to study the luminosity
    aspects at 250 GeV
  • Study the polarization lifetime as a function of
    beam tunes at 250 GeV

13
Polarized proton development plan
  • Luminosity
  • Non-linear chromaticity correction implemented
    in the current Au-Au Run Tepikian, Nikolay, Yun

14
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15
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16
Polarized proton development plan
  • Luminosity
  • Non-linear chromaticity correction implemented
    in the current Au-Au Run
  • 3Qx resonance correction under study by Johan,
    Yun, Rama, Mei,

17
Polarized proton development plan
  • Luminosity
  • Non-linear chromaticity correction implemented
    in the current Au-Au Run
  • 3Qx resonance correction under study
  • Explore new working points
  • (0.92, 0.93) Christoph
  • (0.08, 0.07) Wolfram
  • DA tracking Christoph and Yun
  • Spin tracking Mei, Alfredo
  • Gradient error correction is also under
    development by Todd, Jen and Mei during the
    current Au run
  • This will be first commissioned during the 2008
    pp 100GeV run

18
Polarized proton development plan
  • Luminosity
  • Non-linear chromaticity correction implemented
    in the current Au-Au Run
  • 3Qx resonance correction under study
  • Explore new working points
  • (0.92, 0.93) Christoph
  • (0.08, 0.07) Wolfram
  • DA tracking Christoph and Yun
  • Spin tracking Mei, Alfredo
  • This will be first commissioned during the 2008
    pp 100GeV run
  • Triplet 10 Hz vibration
  • 10 Hz orbit feedback
  • Rebuild tripplet assembly to reduce the 10Hz

19
10 Hz orbit feedback
Feedback ON
feedback OFF
Courtesy of Christoph and Angelika
20
Polarized proton development plan
  • Polarization
  • Improve the orbit control to achieve an orbit
    distortion of 0.3mm or better during the
    acceleration from 100 GeV to 250 GeV
  • Improve the betatron tune and coupling control
    Tune/coupling feedback
  • Snake current setting spin tune measurement

21
  • Need polarized proton to continue the RHIC pp 500
    GeV commissioning
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