Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 3
Book Description
Theory and Suppression of Multibunch Beam Breakup in Linear Colliders
Author: Physics of Intensity Dependent Beam Instabilities
Author: King-Yuen NgPublisher: World Scientific
ISBN: 9812563423
Category : Science
Languages : en
Pages : 798
Book Description
This book provides a comprehensive treatment of intensity dependent particle beam instabilities in accelerating rings. Written for researchers, the material is also suitable for use as a textbook in an advanced graduate course for students studying accelerator physics.The presentation starts with a brief review of the basic concept of wake potentials and coupling impedances in the vacuum chamber followed by a discussion on static and dynamic solutions of their effects on the particle beams. Special emphasis is placed separately on proton and electron machines. Other special topics of interest covered include Landau damping, Balakin-Novokhatsky-Smirnov damping, Sacherer's integral equations, Landau cavity, saw-tooth instability, Robinson stability criteria, beam loading, transition crossing, two-stream instabilities, and collective instability issues of isochronous rings. After the formulation of an instability, readers are provided a thorough description of one or more experimental observations together with a discussion of the cures for the instability.Although the book is theory oriented, the use of mathematics has been minimized. The presentation is intended to be rigorous and self-contained with nearly all the formulas and equations derived.
Degradation of Multibunch Luminosity in a Linear Collider Due to Cumulative Beam Breakup
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Beam-excited transverse wakes in accelerating radiofrequency structures will influence the transverse offsets of each bunch in a multibunch train, causing the projected emittance of the bunch train to grow. An analytic theory of this phenomenon that includes the mitigating influence of a correlated energy spread across the bunch train was recently devised and applied to electron-positron linear colliders. We use the results of this theory to estimate analytically the associated degradation of multibunch luminosity in terms of top-level parameters for the two beams, the two accelerators, and the final-focus system. Then we compare the estimates with results from GUINEA-PIG, a code that includes the detailed physics of beam-beam interactions.
Multibunch Beam Breakup in High Energy Linear Colliders
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The SLAC design for a next-generation linear collider with center-of-mass energy of 0.5 to 1.0 TeV requires that multiple bunches ((approximately)10) be accelerated on each rf fill. At the beam intensity ((approximately)101° particles per bunch) and rf frequency (11--17 GHz) required, the beam would be highly unstable transversely. Using computer simulation and analytic models, we have studied several possible methods of controlling the transverse instability: using damped cavities to damp the transverse dipole modes; adjusting the frequency of the dominant transverse mode relative to the rf frequency, so that bunches are placed near zero crossings of the wake; introducing a cell-to-cell spread in the transverse dipole mode frequencies; and introducing a bunch-to-bunch variation in the transverse focusing. The best cure(s) to use depend on the bunch spacing, intensity, and other features of the final design. 8 refs., 3 figs.
Controlling Multibunch Beam Breakup in TeV Linear Colliders
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
To obtain luminosities near 10TUcm/sup /minus/2/sec/sup /minus/1/ in a TeV linear collider, it will probably be essential to accelerate many bunches per RF fill in order to increase the energy transfer efficiency. In this paper we study the transverse dynamics of multiple bunches in a linac, and we examine the effects of several methods of controlling the beam blow-up that would otherwise be induced by transverse dipole wake fields. The methods we study are: damping the transverse modes, adjusting the frequency of the dominant transverse modes so that bunches may be placed near zero-crossings of the transverse wake, and bunch-to-bunch variation of the transverse focusing. We study the utility of these cures in the main linacs of an example of a TeV collider. 16 refs., 4 figs., 2 tabs.
Unified Theory of Single-bunch and Multi-bunch Beam Breakup in Linacs
Author: Takanori ToyomasuMultibunch Beam Break-up in Detuned Structures
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 3
Book Description
A key problem in next-generation linear collider design utilizing multibunching is the control of multibunch beam break-up. One method of controlling the break-up is detuning, i.e., varying the frequency of the transverse deflecting modes by varying the cell dimensions within the accelerating structures. In this case, the beam breakup is sensitive to the resonances between the bunch frequency and some of the deflecting mode frequencies. It is also sensitive to errors in the fabrication and alignment of the accelerating structures. We examine these effects in the context of the SLAC NLC design.
Suppression of Beam Breakup Instability in a Long Train by Introducing Energy Spread Between the Bunches
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Interaction between the bunches in the NLC main linac via long range wakefields can cause a beam breakup instability. Although the magnitude of the long range wakefields for an ideal NLC structure is below the instability threshold, the wake increases when structure manufacturing errors are taken into account. In case of large errors, the developing instability can result in the projected emittance dilution of the bunch train. To suppress the instability, the authors propose to introduce an energy spread between the bunches, similar to the BNS energy spread for damping of the beam breakup within a single bunch. Based on simple estimates, the authors show that the energy spread of order of 1--2% should be enough for suppression of the instability. The results of computer simulations with the simulation code LIAR confirm theoretical estimates and indicate that both the tolerances for structure misalignments and the incoming beam jitter can be considerably loosened by introducing the energy spread within the beam.
Multibunch Beam Break-up Calculations for a Superconducting TeV Linear Collider Design
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 5
Book Description
Multibunch beam break-up in an example of a next-generation (1 TeV center of mass energy) linear collider utilizing superconducting RF is calculated. The amount of damping of the transverse dipole cavity modes required to control this instability is estimated.
Analytical Formula for Weak Multi-Bunch Beam Break-Up in a Linac
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 6
Book Description
In designing linac structures for multi-bunch applications the authors are often interested in estimating the effect of relatively weak multi-bunch beam breakup (BBU), due to the somewhat complicated wakefields of detuned structures. This, for example, is the case for the injector linacs of the JLC/NLC linear collider project. Deriving an analytical formula for such a problem is the subject of this report. Note that the more studied multi-bunch BBU problem, i.e. the effect on a bunch train of a single strong mode, the so-called cumulative beam break-up instability, is a somewhat different problem, and one for which the approach presented here is probably not very useful.