Simulations that Explain and Predict Beam-Beam Effects in the Tevatron

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Simulations that Explain and Predict Beam-Beam
Effects in the Tevatron

• Alexander Valishev
• Fermilab, Batavia, IL 60510
• LARP Mini-Workshop on Beam-Beam Compensation
• July 2-4, 2007

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Outline

• LIFETRAC code
• Simulations
• Fast emittance blowup
• Proton lifetime
• Antiproton lifetime

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Beam-Beam Code LIFETRAC

• Weak-strong, Gaussian strong bunch
• Macro-particle weak bunch, typically 10000
  particles
• Full details of the machine optics and collision
  pattern with all 72 IPs
• Effects of random noise
• Parallel, up to 107 turns

• D.Shatilov et al., TPAT084, PAC05
• A.Valishev et al., TPAT083, PAC05

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Optics Measurements with LOCO
(cm) (cm)
CDF 32.0 37.1
D0 35.8 40.0
V.Sajaev et al., PAC2005
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Fast Bunch-by-Bunch Effects Orbit
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Fast Bunch-by-Bunch Effects Emittance Growth
(Scallops)
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Scallops Simulation
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Effect of the Helix Size on Lifetime
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Effect of Betatron Tune Chromaticity
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Luminosity Evolution Store 5008,
L2.07E32New Helix. High Proton Tune
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Simulation for Proton Bunch 6 Effect of
Corrected C2
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Simulation for Antiproton Bunch 6 Effect of
Corrected C2
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Comparison of Antiproton Bunch 6 Parameters for 3
Working Points Present Proton Intensity
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Comparison of Antiproton Bunch 6 Parameters for 3
Working Points Proton Intensity Increased by 30
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Summary

• Weak-strong simulation for Tevatron has been
  extensively used to validate proposed changes.
  Results are consistent with experimental data
• Fast (1-5 min) effects can be simulated with
  high detail level
• Longer time (2 hours) can be simulated by
  artificially increasing random noise rate

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Effect of TEL on Proton Lifetime
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Effect of TEL on Proton Spectrum
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Strong-Strong Simulation