Title: Polarized Protons in RHIC at 500 GeV
1Polarized Protons in RHIC at 500 GeV
2RHIC pp design parameter
Achieved performance for Physics Runs
3Luminosity 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
4Polarization performance
- Achieved 100 polarization transmission
efficiency from injection to 100 GeV - Much stronger spin depolarzing resonances from
100 GeV to 250 GeV
5RHIC intrinsic spin resonance spectrum
Design goal
Achieved Physics Run
Intrinsic spin resonance Qx28.73, Qy29.72,
emit 10
6FY 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)
7Overview 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
8What have been achieved?
- Blue beam was first accelerated up to 250 GeV at
the end of FY2006 pp RUN
9pp in blue accelerated to 250 GeV with 45
polarization
250 GeV
injection
Polarization at 250 GeV
Polarization at injection
10What 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
11RHIC pp polarization ramp measurement
12Remaining 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
13Polarized proton development plan
- Luminosity
- Non-linear chromaticity correction implemented
in the current Au-Au Run Tepikian, Nikolay, Yun
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16Polarized 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,
17Polarized 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
18Polarized 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
1910 Hz orbit feedback
Feedback ON
feedback OFF
Courtesy of Christoph and Angelika
20Polarized 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