Download or read book Measurements and Analysis of Longitudinal HOM Driven Coupled Bunch Modes in PEP II Rings written by and published by . This book was released on 2008 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The growth rates of the longitudinal higher-order impedance-driven beam modes have greatly increased since the initial PEP-II design and commissioning. This increase is attributed to the addition of 6 1.2MW RF stations with 8 accelerating cavities in the HER and 2 1.2MW RF stations with 4 accelerating cavities in the LER, which allowed operations at twice the design current and almost four times the luminosity. As a result, the damping requirements for the longitudinal feedback have greatly increased since the design, and the feedback filters and control schemes have evolved during PEP-II operations. In this paper, growth and damping rate data for the higher-order mode (HOM) driven coupled-bunch modes are presented from various PEP-II runs and are compared with historical estimates during commissioning. The effect of noise in the feedback processing channel is also studied. Both the stability and performance limits of the system are analyzed.
Download or read book Radio Frequency Station beam Dynamics Interaction in Circular Accelerators written by Themistoklis Mastoridis and published by Stanford University. This book was released on 2005 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: The longitudinal beam dynamics in circular accelerators is mainly defined by the interaction of the beam current with the accelerating Radio Frequency (RF) stations. For stable operation, Low Level RF (LLRF) feedback systems are employed to reduce coherent instabilities and regulate the accelerating voltage. The LLRF system design has implications for the dynamics and stability of the closed-loop RF systems as well as for the particle beam, and is very sensitive to the operating range of accelerator currents and energies. Stability of the RF loop and the beam are necessary conditions for reliable machine operation. This dissertation describes theoretical formalisms and models that determine the longitudinal beam dynamics based on the LLRF implementation, time domain simulations that capture the dynamic behavior of the RF station-beam interaction, and measurements from the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC) that validate the models and simulations. These models and simulations are structured to capture the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They also provide the opportunity to study diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Coupled-bunch instabilities and RF station power were the performance limiting effects for PEP-II. The sensitivity of the instabilities to individual LLRF parameters, the effectiveness of alternative operational algorithms, and the possible tradeoffs between RF loop and beam stability were studied. New algorithms were implemented, with significant performance improvement leading to a world record current during the last PEP-II run of 3212 mA for the Low Energy Ring. Longitudinal beam emittance growth due to RF noise is a major concern for LHC. Simulations studies and measurements were conducted that clearly show the correlation between RF noise and longitudinal bunch emittance, identify the major LLRF noise contributions, and determine the RF component dominating this effect. With these results, LHC upgrades and alternative algorithms are evaluated to reduce longitudinal emittance growth during operations. The applications of this work are described with regard to future machines and analysis of new technical implementations, as well as to possible future work which would continue the directions of this dissertation.
Download or read book Multi Bunch Longitudinal Dynamics and Diagnostics Via a Digital Feedback System at PEP II DAFNE ALS and SPEAR written by and published by . This book was released on 1999 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: A bunch-by-bunch longitudinal feedback system based on a programmable DSP architecture is used to study coupled-bunch motion and its sources. Experimental results are presented from PEP-II, DA[Phi]NE, ALS and SPEAR to highlight the operational experience from 4 installations, plus show novel accelerator diagnostics possible with the digital processing system. Modal growth and damping rates are measured via short (20 ms) transient recordings for unstable and stable coupled-bunch modes. Data from steady-state measurements are used to identify unstable modes and noise-driven beam motion. A novel impedance measurement technique is presented which reveals the longitudinal impedance as a function of frequency. This technique uses the measured synchronous phase and charge of every bucket to calculate the impedance seen by the beam at revolution harmonics.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the 1993 Particle Accelerator Conference written by and published by . This book was released on 1993 with total page 868 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings written by and published by . This book was released on 1995 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the 1995 Particle Accelerator Conference written by and published by . This book was released on 1996 with total page 766 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coupled Bunch Motion in Large Size Rings written by and published by . This book was released on 1991 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: The growth of the quasi-steady-state motion of the coupled bunch oscillations in storage rings has been studied by means of a normal mode analysis to determine the beam stability. In this type of analysis, the initial amplitude displacements of the bunches are first written as a sum of the normal modes of the multiple bunch system, and then the stability of each mode is determined. If the amplitude of all modes decay then the amplitude of all of the individual bunches must eventually decay, and the motion is considered stable. However, if the beat frequency between the different modes is sufficiently high, compared to the decay rate of the modes, it is possible for the amplitude of some of the bunches to grow temporarily before eventually decaying. Thus, even if all normal modes are eventually damped it is possible during the transient phase for the amplitude of several individual bunch oscillations to grow and become lost. Mathematical complications also arise from a modal analysis when there is a gap in the bunch train and the wake fields from the last bunch in the train decays before arrival of the first bunch; for this case the coupled bunch motion more nearly represents that of beam breakup phenomena observed in linacs. 2 figs.
Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 2092 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book INIS Atomindex written by and published by . This book was released on 1995 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Particle Physics Reference Library written by Stephen Myers and published by Springer Nature. This book was released on 2020-01-01 with total page 867 pages. Available in PDF, EPUB and Kindle. Book excerpt: This third open access volume of the handbook series deals with accelerator physics, design, technology and operations, as well as with beam optics, dynamics and diagnostics. A joint CERN-Springer initiative, the "Particle Physics Reference Library" provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A,B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open access.
Download or read book Physics of Intensity Dependent Beam Instabilities written by King-Yuen Ng and published by World Scientific. This book was released on 2006 with total page 795 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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, BalakinOCoNovokhatskyOCoSmirnov 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."
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1993 with total page 714 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book EPAC 90 written by P. Marin and published by Atlantica Séguier Frontières. This book was released on 1990 with total page 1054 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Elementary Particles Accelerators and Colliders written by Ugo Amaldi and published by Springer. This book was released on 2013-03-27 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: After a historical consideration of the types and evolution of accelerators the physics of particle beams is provided in detail. Topics dealt with comprise linear and nonlinear beam dynamics, collective phenomena in beams, and interactions of beams with the surroundings. The design and principles of synchrotrons, circular and linear colliders, and of linear accelerators are discussed next. Also technological aspects of accelerators (magnets, RF cavities, cryogenics, power supply, vacuum, beam instrumentation, injection and extraction) are reviewed, as well as accelerator operation (parameter control, beam feedback system, orbit correction, luminosity optimization). After introducing the largest accelerators and colliders of their times the application of accelerators and storage rings in industry, medicine, basic science, and energy research is discussed, including also synchrotron radiation sources and spallation sources. Finally, cosmic accelerators and an outlook for the future are given.
Download or read book LHC Design Report written by and published by . This book was released on 2004 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Particle Accelerator Physics written by Helmut Wiedemann and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle Accelerator Physics covers the dynamics of relativistic particle beams, basics of particle guidance and focusing, lattice design, characteristics of beam transport systems and circular accelerators. Particle-beam optics is treated in the linear approximation including sextupoles to correct for chromatic aberrations. Perturbations to linear beam dynamics are analyzed in detail and correction measures are discussed, while basic lattice design features and building blocks leading to the design of more complicated beam transport systems and circular accelerators are studied. Characteristics of synchrotron radiation and quantum effects due to the statistical emission of photons on particle trajectories are derived and applied to determine particle-beam parameters. The discussions specifically concentrate on relativistic particle beams and the physics of beam optics in beam transport systems and circular accelerators such as synchrotrons and storage rings. This book forms a broad basis for further, more detailed studies of nonlinear beam dynamics and associated accelerator physics problems, discussed in the subsequent volume.
