Download or read book Multipass Beam Breakup in Recirculating Linacs written by Joseph J. Bisognano and published by . This book was released on 1987 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Beam Breakup in Recirculating Linacs written by and published by . This book was released on 1991 with total page 2483 pages. Available in PDF, EPUB and Kindle. Book excerpt: In general, a recirculation path length in a recirculating accelerator has to be an integer multiple of RF wavelength if recirculations are all in the same direction. However, it is not necessary to require such a relation to be satisfied with respect to the bunching frequency, when the bunch repetition rate is different from the RF frequency. An analytic model of multipass beam breakup (BBU) in recirculating linacs studied by Bisognano and Gluckstern has been generalized to include the case of a subharmonic bunching scheme in the operation of such linacs.
Download or read book A METHOD TO CONTROL MULTIPASS BEAM BREAKUP IN RECIRCULATING LINACS written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We investigate a method to control the multipass dipole beam breakup instability in a recirculating linac including energy recovery. Effectiveness of an external feedback system for such a goal is shown clearly in a simplified model. We also verify the theoretical result with a simulation study.
Download or read book Tools to Predict Beam Breakup in Recirculating Linacs written by and published by . This book was released on 2003 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important limitation on the maximum beam current in a recirculating linac is due to beam breakup caused by higher order modes (HOM) excited in the RF cavities. A HOM delivers a transverse kick to a beam bunch, the bunch on the next pass can then drive the HOM and cause it to grow until the beam is lost. Two codes, MATBBU1 and TDBBU2, have been written to estimate the threshold current for a set of HOMs and accelerator optics. The relative merits and limitations of each is discussed in detail.
Download or read book Multipass Beam Breakup in Recirculating Linacs written by and published by . This book was released on 1987 with total page 2060 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multipass beam breakup, a transverse beam instability generated by coherent excitation of cavity higher order modes in a recirculating linac, is a particular concern in designs utilizing superconducting technology. In this paper, an analytic model is presented that includes a description of this effect for a distribution of cavities along the linac with several recirculations in an impulse approximation. For N passes and M cvities, solution of the resulting equations reduces in general to finding M zeros of a 2(N-1) dimensional determinant or equivalently the M eigenvalues of an M-dimensional matrix. The parametric dependence of this system on higher order mode frequencies and Q, lattice functions, and transit times is discussed. Numerical examples are presented to clarify these issues and to model the CEBAF superconducting linac, where threshold currents are found to exceed design currents by more than an order of magnitude.
Download or read book A Cure for Multipass Beam Breakup in Recirculating Linacs written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We investigate a method to control the multipass dipole beam breakup instability in a recirculating linac including energy recovery. Effectiveness of an external feedback system for such a goal is shown clearly in a simplified model. We also verify the theoretical result with a simulation study.
Download or read book Beam Breakup in Recirculating Linacs February 1990 written by Byung Yunn and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Beam Breakup in Superconducting Recirculating Linacs written by and published by . This book was released on 1988 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance and operational flexibility of superconducting recirculating linacs can be limited by a variety of collective phenomena which are grouped under the name beam breakup. In this note the various beam breakup phenomena found in recirculating superconducting radio frequency linacs are described and appraised relative to beam performance.
Download or read book Multipass Beam Breakup in Recirculating Linacs July 1986 written by Joseph J. Bisognano and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Beam Breakup Instability in a Recirculating Linac Caused by a Quadrupole Mode written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Following the successful demonstration of energy recovery in a recirculating linac with superconducting cavities at the Jefferson Lab FEL[1], several ambitious electron accelerator projects have recently been proposed or are in study for either a light source or a collider based on this novel technology. These projects all intend to utilize a high quality linac electron beam generated with an average beam current typically in the range of 100's of mA. As is well known, a recirculating linac suffers from a beam breakup instability of a regenerative type caused by a Higher Order Mode (HOM) in an accelerating cavity, which can have a very high Q (quality factor) when superconducting. The instability can degrade the beam quality significantly. We investigate one such beam breakup instability in a recirculating linac that could arise as a result of high Q quadrupole modes excited in the cavity. In a simple model we derive a relation which allows one to deduce the upper limit on tolerable Q ...
Download or read book Expressions for the Threshold Current of Multipass Beam Breakup in Recirculating Linacs from Single Cavity Models written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We investigate multipass beam breakup (BBU) in a recirculating linear accelerator in the framework of a single cavity model. We present expressions for the beam breakup threshold current for various situations derived from a perturbative solution of BBU equations. These formulae should serve as a guide to understand the BBU phenomenon for a particular system and also as a tool to estimate the BBU threshold current quickly. Many of the results presented are more general than previous considerations because they include the effects of coupling between the two transverse polarizations in each dipole higher order mode.
Download or read book Beam Break Up Analysis for the Berkeley Recirculating Linac Light Source written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe here a study of a single bunch Beam Break Up (BBU) instability for a proposed Berkeley fast x-ray facility based on a recirculating linac [1]. The recirculating linac employs a 600 MeV superconducting RF linear accelerator and the electron beam energy of [approx] 2.5 GeV is reached over four beam passes through the linac. A 120 MeV superconducting RF linear accelerator is used as an injector to the recirculating linac. The machine parameters are listed in Appendix A. The equation describing the transverse displacement x(s, z) of the electrons in an accelerated bunch, as a function of their longitudinal position within the bunch z, can be written in the form [2]: d/ds[[gamma](s) dx/ds] + k[sup 2](s)[gamma](s)x(s, z) = r[sub 0][integral][sub z][sup [infinity]][rho](z')W[sub [perpendicular]](z'-z)x(s, z')dz' (1) where [gamma] is the relativistic factor, k the focusing strength, r[sub 0] the classical electron radius, [rho] the bunch density, W[sub [perpendicular]] the transverse wake function per unit length and s indicates the position along the linac. We assume infinitesimally small transverse beam dimensions (a good approximation, when the bunch dimensions are much less than the size of the beam pipe), so that x has to be interpreted as the displacement of the centre of a bunch slice. We also assume a bunch length much less than the betatron wavelength, therefore the displacement in the RHS of Eq.(1) is not retarded and, finally, we use an average transverse wake function obtained averaging the calculated short range wake of a single cavity [2] over the linac length. At first we consider the effect associated with a displacement of the electron bunch at the injection into the perfectly aligned linac. Later we extend the analysis to the case of misalignments of the linac RF cavities and cryomodules. Throughout the paper we compare the results obtained to the output of a simple tracking code, written as a Mathematical notebook. In order to keep the analytical expressions reasonably simple, we model the linac length as entirely filled with RF cavities (thus neglecting all the drift spaces, accounting for as much as one third of the total length). This causes the wakefield intensity used in the analysis to be bigger than the actual value and the average accelerating gradient to be smaller. It is shown in the paper that this corresponds to a conservative estimate of the BBU growth.
Download or read book Calculating Beam Breakup in Superconducting Linear Accelerators written by and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As the intensity of a particle beam passing through a linear accelerator is raised, interactions between particles play an increasingly prominent role in determining the overall dynamics of the beam. These many body effects, known collectively as beam breakup, tend to degrade the quality of the transported beam, and hence they must be calculated to accurately predict the evolution of the beam as it traverses the accelerator. Several codes which compute various collective effects have been developed and used to simulate the dynamics of beams passing through superconducting accelerator structures. All the codes use the same basic algorithm: the beam is tracked through elements giving the focusing forces on the particles, and at the appropriate locations in the linac, localized forces are impressed on the particles which model the electromagnetic interactions. Here, a difficulty is that the usual ''Coulomb'' interaction between particles is changed by the electromagnetic environment of the accelerator. By such calculations it has been shown that recirculating linear accelerators such as the one being built at the Continuous Electron Beam Accelerator Facility (CEBAF) should remain stable against multipass beam breakup instability as long as the average current does not exceed about 20 mA, that the beam quality at CEBAF will be degraded when the single bunch charge approaches 109 electrons, and that the beam quality of superconducting linacs that are optimized for high current transport begins to decrease at around 101° electrons per bunch. The latter result is of interest to individuals who would use superconducting linacs as beam sources for free electron lasers or for superconducting colliders for high energy physics research.
Download or read book Multipass Beam Breakup in Energy Recovery Linacs written by T. I. Smith and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper is a compilation of several presentations on multipass beam breakup (BBU) in energy recovery linacs (ERL) given at the 32nd Advanced ICFA Beam Workshop on ERLs. The goal of this paper is to summarize the progress achieved in analytical, numerical, and experimental studies of the instability and outline available and proposed BBU mitigation techniques. In this paper, a simplified theory of multipass BBU in recirculating linacs is presented. Several BBU suppression techniques and their working principles are discussed. The paper presents an overview of available BBU codes. Results of experimental studies of multipass BBU at the Jefferson Laboratory (JLab) FEL Upgrade are described.
Download or read book Beam Breakup Simulations of the Saclay Recirculation Linac October 1986 written by Geoffrey Krafft and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Higher order modes and Beam Breakup Simulations in the Jefferson Lab FEL Recirculating Linac written by Lia Merminga and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multipass Beam Breakup Study at Jefferson Lab for the 12 GeV CEBAF Upgrade written by Ilkyoung Shin and published by . This book was released on 2013 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:
