f LHC elens simulations Alexander Valishev LARP CM

f LHC e-lens simulations Alexander Valishev LARP CM, 4/23/2008

f Tevatron Head-on Beam-Beam Tuneshift LARP CM 4/23/08 – A. Valishev 2

f Possible Use of E-Lens V. Shiltsev, LHC BBC Workshop, SLAC 2007 LARP CM 4/23/08 – A. Valishev 3

f The Simulation § Weak-Strong macro particle code LIFETRAC. Ø Ø 3 D Gaussian strong bunch LR and HO 6 D tracking. Weak bunch sliced at IPs 104 particles for 107 turns § Machine Ø 6 D maps, collision points and beam separations from mad-x (ideal linear optics V. 6. 5) Ø 1 st and 2 nd order chromaticity Ø Diffusion Ø Aperture at 6 sigma § E-Lens Ø Gaussian e-beam profile Ø Location at bbc section near IP 1 Ø Size and position matched to proton beam LARP CM 4/23/08 – A. Valishev 4

f Nominal Bunch Intensity Evolution LARP CM 4/23/08 – A. Valishev 5

f Nominal Bunch Emittance and Spectra LARP CM 4/23/08 – A. Valishev 6

f Effect of LR and HO Collisions LARP CM 4/23/08 – A. Valishev 7

f Effect of E-Lens at x=0. 0075 LARP CM 4/23/08 – A. Valishev 8

f Effect of E-Lens on Beam Lifetime LARP CM 4/23/08 – A. Valishev 9

f 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 Ø Effect of e-beam size, stability, and alignment Ø E-Lens as RDT compensator Ø Machine imperfections LARP CM 4/23/08 – A. Valishev 10

f Backup Slides

f Pacman Bunch 152 x=. 00375 x=. 0075 LARP CM 4/23/08 – A. Valishev 12

f Effect of E-Lens on Beam Lifetime LARP CM 4/23/08 – A. Valishev 13

f 1 E-Lens vs. 2 -Elenses. x=0. 00375 LARP CM 4/23/08 – A. Valishev 14

f Effect of E-Beam Size. x=0. 01 LARP CM 4/23/08 – A. Valishev 15