Download or read book Halo Formation and Hollowing in Relativistic Electron Beams written by Richard F. Hubbard and published by . This book was released on 1988 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: A relativistic electron beam propagating through dense gas may evolve to a variety of current density profiles J sub b (r) depending on the beam temperature T and plasma current profile J sup P (r). Four broad classes of equilibria are identified in particle simulations: (1) Bennett-like or compact, (2) core and halo, (3) on-axis hollowed and (4) off-axis hollowed. The qualitative features of each class are reproduced in a simple analytical model which assumes an isothermal beam and a Bennett plasma current profile and iterates about an initial ansatz of a Bennett beam current profile. Bennett-like equilibria are produced when the return current fraction f is small or when T/T sub B = 1-f, where T sub B> 1-f and moderate or high f, the equilibrium consists of a compact core surrounded by a halo which may contain most of the beam current. In extreme cases (T/T sub B” 1-f and f close to unity), an off-axis density minimum occurs. (This is also referred to as off-axis hollowing.) For T/T sub B

Download or read book Beam Halo Dynamics and Control With Hollow Electron Beams written by and published by . This book was released on 2012 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hollow Electron Beam Collimation for HL LHC Effect on the Beam Core written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Collimation with hollow electron beams or lenses (HEL) is currently one of the most promising concepts for active halo control in HL-LHC. In previous studies it has been shown that the halo can be efficiently removed with a hollow electron lens. Equally important as an efficient removal of the halo, is also to demonstrate that the core stays unperturbed. In this paper, we present a summary of the experiment at the LHC and simulations in view of the effect of the HEL on the beam core in case of a pulsed operation.

Download or read book Conceptual Design of Hollow Electron Lenses for Beam Halo Control in the Large Hadron Collider written by and published by . This book was released on 2014 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Collimation with hollow electron beams is a technique for halo control in high-power hadron beams. It is based on an electron beam (possibly pulsed or modulated in intensity) guided by strong axial magnetic fields which overlaps with the circulating beam in a short section of the ring. The concept was tested experimentally at the Fermilab Tevatron collider using a hollow electron gun installed in one of the Tevatron electron lenses. We are proposing a conceptual design for applying this technique to the Large Hadron Collider at CERN. A prototype hollow electron gun for the LHC was built and tested. The expected performance of the hollow electron beam collimator was based on Tevatron experiments and on numerical tracking simulations. Halo removal rates and enhancements of halo diffusivity were estimated as a function of beam and lattice parameters. Proton beam core lifetimes and emittance growth rates were checked to ensure that undesired effects were suppressed. Hardware specifications were based on the Tevatron devices and on preliminary engineering integration studies in the LHC machine. Required resources and a possible timeline were also outlined, together with a brief discussion of alternative halo-removal schemes and of other possible uses of electron lenses to improve the performance of the LHC.

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electron Beam Halo Formation in High power Periodic Permanent Magnet Focusing Klystron Amplifiers written by Renato Pakter and published by . This book was released on 2000 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Formation of Relativistic Electron Beam Rings in a Conducting Cavity written by Akihiro Mohri and published by . This book was released on 1982 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Self Focusing of Relativistic Electron Bunches in Plasma written by Valery B. Krasovitskii and published by Nova Publishers. This book was released on 2008 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the non-linear theory of electrostatic focusing of an electron beam split into bunches under conditions when the plasma permittivity at the modulation frequency is negative and the effective Coulomb force acting on the electron bunches is reversed. Conditions for the spatial equilibrium between the bunch and plasma emission, as well as the dynamics of the formation of focussed bunches, are confirmed by solving (both analytically and numerically) the self-consistent set of equations.

Download or read book Halo Formation And Emittance Growth of Positron Beams in Plasmas written by and published by . This book was released on 2011 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: An ultrarelativistic 28.5 GeV, 700-[mu]m-long positron bunch is focused near the entrance of a 1.4-m-long plasma with a density n{sub e} between ≈1013 and ≈5 x 1014 cm−3. Partial neutralization of the bunch space charge by the mobile plasma electrons results in a reduction in transverse size by a factor of ≈3 in the high emittance plane of the beam ≈1 m downstream from the plasma exit. As n{sub e} increases, the formation of a beam halo containing ≈40% of the total charge is observed, indicating that the plasma focusing force is nonlinear. Numerical simulations confirm these observations. The bunch with an incoming transverse size ratio of ≈3 and emittance ratio of ≈5 suffers emittance growth and exits the plasma with approximately equal sizes and emittances.

Download or read book Physics Briefs written by and published by . This book was released on 1990 with total page 1266 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Creation Transport and Measurement of Bright Relativistic Electron Beams written by Chad Bennett McKee and published by . This book was released on 1994 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies of Proton Driven Plasma Wakefield Acceleration written by Yangmei Li and published by Springer Nature. This book was released on 2020-07-15 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on a cutting-edge area of research, which is aligned with CERN's mainstream research, the "AWAKE" project, dedicated to proving the capability of accelerating particles to the energy frontier by the high energy proton beam. The author participated in this project and has advanced the plasma wakefield theory and modelling significantly, especially concerning future plasma acceleration based collider design. The thesis addresses electron beam acceleration to high energy whilst preserving its high quality driven by a single short proton bunch in hollow plasma. It also demonstrates stable deceleration of multiple proton bunches in a nonlinear regime with strong resonant wakefield excitation in hollow plasma, and generation of high energy and high quality electron or positron bunches. Further work includes the assessment of transverse instabilities induced by misaligned beams in hollow plasma and enhancement of the wakefield amplitude driven by a self-modulated long proton bunch with a tapered plasma. This work has major potential to impact the next generation of linear colliders and also in the long-term may help develop compact accelerators for use in industrial and medical facilities.

Download or read book Government Reports Annual Index written by and published by . This book was released on 1994 with total page 1688 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applications of Electron Lenses written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Hollow electron beam collimation and halo control were studied as an option to complement the collimation system for the upgrades of the Large Hadron Collider (LHC) at CERN; a conceptual design was recently completed. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles. At Fermilab, we are planning to install an electron lens in the Integrable Optics Test Accelerator (IOTA, a 40-m ring for 150-MeV electrons) as one of the proof-of-principle implementations of nonlinear integrable optics to achieve large tune spreads and more stable beams without loss of dynamic aperture.

Download or read book Compression of Intense Relativistic Electron Beams written by Harry Edward Davitian and published by . This book was released on 1973 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theoretical Studies of Intense Relativistic Electron Beam plasma Interactions written by Sidney Darwin Putnam and published by . This book was released on 1972 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bunching of Relativistic Electron Beams at Optical Frequencies by the Stimulated Cerenkov Interaction written by Danny Y. Wang and published by . This book was released on 1983 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: