LHC elens simulations

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LHC e-lens simulations

• Alexander Valishev
• LARP CM, 4/23/2008

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Tevatron Head-on Beam-Beam Tuneshift
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Possible Use of E-Lens
V.Shiltsev, LHC BBC Workshop, SLAC 2007
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The Simulation

• Weak-Strong macro particle code LIFETRAC.
• 3D Gaussian strong bunch
• LR and HO
• 6D tracking. Weak bunch sliced at IPs
• 104 particles for 107 turns
• Machine
• 6D maps, collision points and beam separations
  from
• mad-x (ideal linear optics V. 6.5)
• 1st and 2nd order chromaticity
• Diffusion
• Aperture at 6 sigma
• E-Lens
• Gaussian e-beam profile
• Location at bbc section near IP1
• Size and position matched to proton beam

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Nominal Bunch Intensity Evolution
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Nominal Bunch Emittance and Spectra
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Effect of LR and HO Collisions
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Effect of E-Lens at x0.0075
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Effect of E-Lens on Beam Lifetime
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Conclusions

• Beam-Beam effects cause lifetime degradation in
  the present configuration at doubled beam
  intensity
• Losses are induced by the combination of LR and
  HO collisions
• E-lens acting as tune spread compensator is
  helpful for improving lifetime
• Questions to be studied
• Effect of e-beam size, stability, and alignment
• E-Lens as RDT compensator
• Machine imperfections

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Backup Slides
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Pacman Bunch 152
x.00375
x.0075
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Effect of E-Lens on Beam Lifetime
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1 E-Lens vs. 2-Elenses. x0.00375
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Effect of E-Beam Size. x0.01