ICAP2012 - List of Keywords (beam-beam-effects)

Paper	Title	Other Keywords	Page
WEAAC2	Simulation of Baseband BTFs Using a Particle-in-cell Code	simulation, lattice, proton, diagnostics	121
	P.A. Görgen TEMF, TU Darmstadt, Darmstadt, Germany O. Boine-Frankenheim GSI, Darmstadt, Germany W. Fischer, S.M. White BNL, Upton, Long Island, New York, USA
	A simulation model for transverse bunched beam transfer functions (BTFs) at the base harmonic is presented. It is based on a code including different machine effects, most notably transverse space charge using a two-dimensional (2D) Poisson solver. A simplified model for the simulation of the strong-strong beam-beam effect was implemented using either 2D field data or analytic expressions under the assumption of Gaussian beams for the beam-beam interaction. The validity of the BTF model is verified based on the comparison of BTF and Schottky spectra features with analytic expectations from literature. The simulation model is then applied to the RHIC proton lattice. A linear transfer map is used between interaction points. BTFs including the beam-beam effect are simulated. Measurements are compared to simulation results at machine conditions.
	Slides WEAAC2 [2.829 MB]

WESAI3	Simulating the Wire Compensation of LHC Long-range Beam-beam Effects	optics, simulation, resonance, luminosity	135
	T.L. Rijoff, F. Zimmermann CERN, Geneva, Switzerland
	The performance of the Large Hadron Collider (LHC) and its minimum crossing angle are limited by long-range beam-beam collisions. Wire compensators can mitigate part of the long-range effects. We perform simulations to explore the efficiency of the compensation at possible wire locations by examining the tune footprint and the dynamic aperture. Starting from the weak-strong simulation code BBTrack we developed a new Lyapunov calculation tool, which seems to better diagnose regular or chaotic particle behavior. We also developed faster ways to execute the simulation and the post-processing. These modifications have allowed us to study different wire positions (longitudinal and transverse), varying wire currents, several wire shapes, and a range of beam-beam crossing angles, in view of a prototype wire installation in the LHC foreseen for 2014/15. Our simulations demonstrate that the wire can provide a good compensation,also for reduced crossing angle. Benefits of an LHC wire compensator include a better overlap of colliding bunches,as well as the possibility of smaller β^* or higher beam current
	Slides WESAI3 [17.486 MB]

Paper

Title

Other Keywords

Page

WEAAC2

Simulation of Baseband BTFs Using a Particle-in-cell Code

simulation, lattice, proton, diagnostics

121

P.A. Görgen
TEMF, TU Darmstadt, Darmstadt, Germany
O. Boine-Frankenheim
GSI, Darmstadt, Germany
W. Fischer, S.M. White
BNL, Upton, Long Island, New York, USA

A simulation model for transverse bunched beam transfer functions (BTFs) at the base harmonic is presented. It is based on a code including different machine effects, most notably transverse space charge using a two-dimensional (2D) Poisson solver. A simplified model for the simulation of the strong-strong beam-beam effect was implemented using either 2D field data or analytic expressions under the assumption of Gaussian beams for the beam-beam interaction. The validity of the BTF model is verified based on the comparison of BTF and Schottky spectra features with analytic expectations from literature. The simulation model is then applied to the RHIC proton lattice. A linear transfer map is used between interaction points. BTFs including the beam-beam effect are simulated. Measurements are compared to simulation results at machine conditions.

Slides WEAAC2 [2.829 MB]

WESAI3

Simulating the Wire Compensation of LHC Long-range Beam-beam Effects

optics, simulation, resonance, luminosity

135

T.L. Rijoff, F. Zimmermann
CERN, Geneva, Switzerland

The performance of the Large Hadron Collider (LHC) and its minimum crossing angle are limited by long-range beam-beam collisions. Wire compensators can mitigate part of the long-range effects. We perform simulations to explore the efficiency of the compensation at possible wire locations by examining the tune footprint and the dynamic aperture. Starting from the weak-strong simulation code BBTrack we developed a new Lyapunov calculation tool, which seems to better diagnose regular or chaotic particle behavior. We also developed faster ways to execute the simulation and the post-processing. These modifications have allowed us to study different wire positions (longitudinal and transverse), varying wire currents, several wire shapes, and a range of beam-beam crossing angles, in view of a prototype wire installation in the LHC foreseen for 2014/15. Our simulations demonstrate that the wire can provide a good compensation,also for reduced crossing angle. Benefits of an LHC wire compensator include a better overlap of colliding bunches,as well as the possibility of smaller β^* or higher beam current

Slides WESAI3 [17.486 MB]