PAC07 - List of Keywords (beam-beam-effects)

A B C D E F G H I K L M O P Q R S T U V W

beam-beam-effects

Paper	Title	Other Keywords	Page
TUOCKI01	Review of Recent Tevatron Operations	luminosity, antiproton, proton, electron	719
	R. S. Moore
	Fermilab's Tevatron proton-antiproton collider continues to improve its luminosity performance at the energy frontier root(s) = 1.96 TeV. The recent Tevatron operation will be reviewed and notable tasks leading to advancements will be highlighted. The topics to be covered include: work performed during the 14-week shutdown in 2006, improved helical orbits, automatic orbit stabilization during high-energy physics (HEP) stores, optics corrections, improvements in the quench protection system, and avenues to maximizing the integrated luminosity delivered to the CDF and D0 experiments.
	Slides

TUOCKI03	Observations and Modeling of Beam-Beam Effects at the Tevatron Collider	proton, antiproton, luminosity, collider	725
	A. Valishev Y. Alexahin, V. A. Lebedev, R. S. Moore, V. D. Shiltsev Fermilab, Batavia, Illinois
	This report summarizes recent experience with beam-beam effects at the Tevatron collider. Improvements in the beam life time resulting from implementation of the new helical orbit are analyzed. Effects of second order chromaticity correction and beam-beam compensation with Electron Lenses are studied.
	Slides

TUOCKI04	Experimental Demonstration of Beam-Beam Compensation by Tevatron Electron Lenses and Prospects for the LHC	electron, proton, luminosity, collider	728
	V. D. Shiltsev Y. Alexahin, V. Kamerdzhiev, G. F. Kuznetsov, X. Zhang Fermilab, Batavia, Illinois K. Bishofberger LANL, Los Alamos, New Mexico
	We report the first experimental demonstration of compensation of beam-beam interaction effects with use of electron beams. Long-range and head-on interactions of high intensity proton and antiproton beams have been dominating sources of beam loss and lifetime limitations in the Tevatron in Collider Run II (2001-present). Electron lense acting on proton bunches has doubled their lifetime by compensating beam-beam interaction with antiprotons. We present results of the experiments, operational details and discuss possibilities of using electron lenses for beam-beam compensation in LHC.
	Slides

TUPAS024	Experimental and Simulation Studies of Beam-Beam Compensation with Tevatron Electron Lenses	proton, electron, simulation, antiproton	1703
	V. Kamerdzhiev Y. Alexahin, V. D. Shiltsev, A. Valishev, X. Zhang Fermilab, Batavia, Illinois D. N. Shatilov BINP SB RAS, Novosibirsk
	Initially the Tevatron Electron Lenses (TELs) were intended for compensation of the beam-beam effect on the antiproton beam. Owing to recent increase in the number of antiprotons and reduction in their emittance, it is the proton beam now that suffers most from the beam-beam effect. We present results of beam studies, compare them with the results of computer simulations using LIFETRAC code and discuss possibilities of further improvements of the Beam-Beam Compensation efficiency in the Tevatron.

TUPAS095	Experiments with a DC Wire in RHIC	beam-losses, simulation, emittance, proton	1859
	W. Fischer N. P. Abreu, R. Calaga, G. Robert-Demolaize BNL, Upton, Long Island, New York U. Dorda, J.-P. Koutchouk, F. Zimmermann CERN, Geneva A. C. Kabel SLAC, Menlo Park, California H. J. Kim, T. Sen Fermilab, Batavia, Illinois J. Qiang LBNL, Berkeley, California
	Funding: Work supported by U. S. DOE under contract No DE-AC02-98CH1-886. A DC wire has been installed in RHIC to explore the long-range beam-beam effect, and test its compensation. We report on experiments that measure the effect of the wire's electro-magnetic field on the beam's lifetime and tune distribution, and accompanying simulations.

THPMN008	Evaluation of Luminosity Reduction in the ILC Head-on Scheme from Parasitic Collisions	luminosity, simulation, extraction, injection	2722
	J. Brossard M. Alabau IFIC, Valencia D. A.-K. Angal-Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire P. Bambade, T. Derrien LAL, Orsay O. Napoly, J. Payet CEA, Gif-sur-Yvette
	An interaction region with head-on collisions is being developed for the ILC as an alternative to the base line 14 mrad crossing angle design, motivated by simpler beam manipulations upstream of the interaction point and a more favourable configuration for the detector and physics analysis. The design of the post-collision beam line in this scheme involves however a number of technological challenges, one of which is the strength requirement for the electrostatic separators placed immediately after the final doublet to extract the spent beam. In this paper, we examine in detail the main mechanism behind this requirement, the multi-beam kink instability, which results from the long-range beam-beam forces at the parasitic crossings after the bunches have been extracted. Our analysis uses realistic bunch distributions, the Guinea-Pig program to treat beam-beam effects at the interaction point and the DIMAD program to track the disrupted beam distributions in the post-collision beam line. A version of the beam-beam deflection based interaction point feedback system with an improved filtering algorithm is also studied to mitigate the luminosity deterioration from the instability.

THPAN007	Parallel Beam-Beam Simulation Incorporating Multiple Bunches and Multiple Interaction Regions	simulation, collider, interaction-region, betatron	3235
	F. W. Jones W. Herr CERN, Geneva T. Pieloni EPFL, Lausanne
	The simulation code COMBI has been developed to enable the study of beam-beam effects in the full collision scenario of the LHC, with multiple bunches interacting at multiple head-on and long-range collision points. The code is structured in a general way, allowing any number of bunches and interaction points (IP's) and procedural options for collisions, beam transport, and output of statistics and coherent mode data. The scale of this problem escalates into the parallel computing arena, and herein we will describe the construction of an MPI-based version of COMBI able to utilize arbitrary numbers of processors to support efficient calculation of multi-bunch multi-IP interactions and transport. After an overview of the basic methods and numerical components of the code, the computational framework will be described in detail and the parallel efficiency and scalability of the code will be evaluated.

THPAN060	3D PIC Method Development for Simulation of Beam-Beam Effects in Supercolliders	simulation, electron, positron, focusing	3366
	M. A. Boronina E. Levichev, S. A. Nikitin BINP SB RAS, Novosibirsk V. N. Snytnikov IC SB RAS, Novosibrsk V. A. Vshivkov ICM&MG SB RAS, Novosibirsk
	A new Beam-Beam simulation code based on a 3D PIC method has been developed. Taking into account to the full extent the three-dimensional nature of the interaction can be useful for studies of some thin questions such as a pinch effect at large crossing angles in ILC and Crab Waist properties in SuperB Factory. Colliding electron and positron beams move in the region shaped as parallelepiped. The physical process is described by Vlasov-Liouville equations and a set of Maxwell equations that interrelate of the densities of charge and current, and intensities of electric and magnetic fields. The examples of the electron and positron bunches movement and collision simulation are presented.

THPAS062	Recent Progress in a Beam-Beam Simulation Code for Circular Hadron Machines	lattice, simulation, sextupole, storage-ring	3627
	A. C. Kabel W. Fischer BNL, Upton, Long Island, New York T. Sen Fermilab, Batavia, Illinois
	Over the past years, we have developed a set of codes (PLIBB and NIMZOVICH) applicable to weak-strong and strong-strong beam-beam interactions in hadron machines. We have unified these codes into a single application and augmented the modeled physics to include arbitrary-order magnetic elements, noise sources and wire compensators; algorithmic improvements include diferential-algebraic methods, thick magnetic elements, and a fully-coupled, six-dimensional and symplectic treatment of lumped sections. A novel weighted-macroparticle approach allows for the immediate calculation of very low beam loss rates by particle tracking. The parallelization scheme of the code allows for a highly efficient simulation of colliders with a high number of parasitic crossings and/or pronounced hourglass effect in the IP. Areas of applicability include the LHC and the wire-compensation experiments performed at RHIC. Typical results will be presented.

FRPMS096	Emittance Growth due to Beam-Beam Effect in RHIC	emittance, simulation, proton, luminosity	4306
	J. Beebe-Wang
	Funding: Work performed under the United States Department of Energy Contract No. DE-AC02-98CH1-886. The beam-beam interaction has a significant impact on the beam emittance growth and the luminosity lifetime in RHIC. A simulation study of the emittance growth was performed using the Lifetrac code. The operational conditions of RHIC 2006 100GeV polarized proton run were used in the study. In this paper, the result of this study is presented and compared to the experimental measurements.