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 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 Energy Research Abstracts written by and published by . This book was released on 1987 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1988 with total page 1020 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 1986 Linear Accelator Conference Proceedings written by and published by . This book was released on 1986 with total page 662 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the 1987 IEEE Particle Accelerator Conference written by Eric R. Lindstrom and published by . This book was released on 1987 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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:

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 Two Dimensional Simulations of Multipass Beam Breakup written by and published by . This book was released on 1987 with total page 2060 pages. Available in PDF, EPUB and Kindle. Book excerpt: A vectorized two dimensional beam breakup code, TDBBU, is used to simulate bunch dynamics in recirculating accelerators. First, the code is briefly described, including effects needed to accurately model the CEBAF accelerator. Next, various code test are sketched. Finally, the multipass beam breakup threshold current is determined to be from 10-20 mA for the CEBAF accelerator, a result in agreement with other calculations of the threshold current.

Download or read book Multipass Beam Breakup in the CEBAF Superconducting Linac written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Beam breakup (BBU) instabilities in superconducting linacs are a significant issue due to the potentially high Q values of the cavity higher order modes (HOMs). The CEBAF accelerator, which employs high CW current and 5- pass recirculation through two superconducting linacs, poses unique instability problems. An experimental investigation of multipass BBU along with energy recovery has been completed using a single recirculation through the CEBAF injector linac. Experimental results are compared with computer simulation of multipass BBU.

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 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 Government Reports Announcements Index written by and published by . This book was released on 1988 with total page 1132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Scaling of Wakefield Effects in Recirculating Linacs written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Expressions for the induced energy spread and emittance degradation of a single bunch due to the longitudinal and transverse impedance of rf cavities at the end of a linac structure are presented. Scaling of the formulae with rf frequency is derived. Scaling of the threshold current for the multibunch, multipass beam breakup (BBU) instability in recirculating linacs with accelerator and beam parameters is also derived.