A5070367991- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Magnetic confinement fusion research
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Gyrotron and Vacuum Electronics Research
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Laser-Plasma Interactions and Diagnostics
- Nonlinear Photonic Systems
- Quantum chaos and dynamical systems
- Plasma Diagnostics and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Molecular Physics
- Advanced Data Processing Techniques
- Technical Engine Diagnostics and Monitoring
- Quantum, superfluid, helium dynamics
- Laser Design and Applications
- Mass Spectrometry Techniques and Applications
- Nonlinear Waves and Solitons
- Quantum optics and atomic interactions
- Laser-induced spectroscopy and plasma
- Mechanical and Optical Resonators
- Advanced Optical Imaging Technologies
- Synthesis and Reactivity of Sulfur-Containing Compounds
Fermi National Accelerator Laboratory
1998-2021
Oak Ridge National Laboratory
2003-2014
Brookhaven National Laboratory
2010
China Spallation Neutron Source
2007
Spallation Neutron Source
2006
United States Department of Energy
2006
Indiana University Bloomington
2003
All-Russian Scientific Research Institute of Soybean
1998
Budker Institute of Nuclear Physics
1997
Integrable systems appeared in physics long ago at the onset of classical dynamics with examples being Kepler's and other famous problems. Unfortunately, majority nonlinear problems turned out to be nonintegrable. In accelerator terms, any 2D nonintegrable mapping produces chaotic motion a complex network stable unstable resonances. Nevertheless, proximity an integrable system full volume such is small. Thus, accelerators has potential introduce large betatron tune spread suppress...
The beam-beam interaction in the Tevatron collider sets limits on bunch intensity and luminosity. These are caused by a tune spread each which is mostly due to head-on collisions, but there also bunch-to-bunch parasitic collisions multibunch operation. We propose compensate these effects with use of countertraveling electron beam, we present general considerations physics limitations this technique.
Thin carbon foils are used as strippers for charge exchange injection into high intensity proton rings. However, the stripping become radioactive and produce uncontrolled beam loss, which is one of main factors limiting power in Recently, we presented a scheme laser an ${\mathrm{H}}^{\ensuremath{-}}$ Spallation Neutron Source (SNS) ring. First, atoms converted to ${\mathrm{H}}^{0}$ by magnetic field, then excited from ground state upper levels laser, states protons field. In this paper...
The wake forces produced by a beam bunch can be reduced making the vacuum chamber cross section axially asymmetric. Furthermore, asymmetry results in betatron tune shift for particles tail of bunch. As result, transverse instabilities should significantly suppressed an asymmetric chamber.
XAL is an application programming framework used at the Spallation Neutron Source (SNS) project in Oak Ridge. It written Java, and provides users with a hierarchal view of accelerator. Features include database configuration accelerator structure, online envelope model that configurable from design or live machine values, for quickstart GUI development, scripting interface algorithm common toolkit shared resources. To date, about 25 applications have been written, many which are extensively...
We present a particle core model study of the space charge effect on high intensity synchrotron beams, with specific emphasis Proton Storage Ring (PSR) at Los Alamos National Laboratory. Our formulation includes realistic lattice focusing and dispersion. transport both matched mismatched beams through real structure compare results those an equivalent uniform-focusing approximation. The effects finite momentum spread resonance behavior are specifically targeted. Stroboscopic maps envelope...
Uncontrolled beam losses due to space-charge-induced halo generation are a concern in high intensity rings, which characterized by intensities and low uncontrolled loss requirements. It is therefore important investigate the dynamics of space charge rings. We report here results extensive calculations using particle-tracking approach with self-consistent particle-in-cell model alternatively particle core model. find that inclusion forces provides agreement between calculated experimentally...
Finding self-consistent distributions of beam particles interacting with each other via the space charge force is one challenges accelerator physics. Exactly solvable models are used for simulation benchmarks, instability threshold calculations, etc. Since such have been found only in and two dimensions (Kapchinsky-Vladimirsky distribution), it not possible to apply them a general three dimensional motion. This paper shows how construct new sets distributions, extending even case.
This paper presents a scheme for three-step laser-based stripping of an ${\mathrm{H}}^{\ensuremath{-}}$ beam charge exchange injection into high-intensity proton ring. First, atoms are converted to ${\mathrm{H}}^{0}$ by Lorentz in strong magnetic field, then neutral hydrogen excited from the ground state upper levels laser, and remaining electron, now more weakly bound, is stripped field. The energy spread particles gives rise Doppler broadened absorption linewidth, which makes inefficient...
What prevents us from building super-high intensity accelerators? The answer is case-specific, but it often points to one of the following phenomena: machine resonances, various tune shifts (and spreads), and instabilities. These three phenomena are interdependent in all present machines. In this paper we propose a path toward alleviating these by making accelerators nonlinear. This idea not new: Orlov (1963) McMillan (1967) have proposed initial ideas on nonlinear focusing systems for...
The use of nonlinear lattices with the large betatron tune spreads can increase instability and space charge thresholds by orders magnitude compared to typical linear accelerator lattices. Unfortunately, strong fields create, in general, resonances chaotic motion. This shrinks dynamic aperture impractical values, thus erasing all benefits from their use. Previously known examples stable regular motion special lenses were related one-dimensional or round beams. However, no solution has been...
Nonlinear optics is a promising idea potentially opening the path towards achieving super high beam intensities in circular accelerators. Creation of tune spread reaching 50% betatron would provide strong Landau damping and make immune to instabilities. Recent theoretical work has identified possible way implement stable nonlinear by incorporating focusing elements into specially designed machine lattice. In this report we propose design test accelerator for proof-of-principle experiment. We...
This article is devoted to stability analysis of the antiproton beam interacting with an electron in ``electron lens'' setup for beam-beam compensation Tevatron collider. Electron space charge forces cause transverse ``head-tail'' coupling within bunch which may lead a mode instability (TMCI). We present theory, analytical studies, and numerical simulations this effect. An estimate threshold longitudinal magnetic field necessary avoid given. Dependence on parameters studied.
The Spallation Neutron Source accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to liquid mercury target for neutron scattering research. complex consists of an H-injector, capable producing one-ms-long pulses at 60 Hz repetition rate with 38 mA peak current, 1 GeV linear accelerator, accumulator ring and associated transport lines. 2.5 MeV from the Front End is accelerated 86 in Drift Tube Linac, then 185 Coupled-Cavity Linac finally Superconducting Linac. With completion...
Injection is key in the low-loss design of high-intensity proton facilities like Spallation Neutron Source (SNS). During both accumulator and rapid-cycling-synchrotron version SNS, extensive comparison has been made to select injection scenarios that satisfy SNS's criteria. This paper presents issues considerations pertaining final choice SNS systems.
Transverse mode coupling instability is one of the major limitations a single bunch current in storage rings. Until now it has appeared large electron-positron machines, while its presence proton colliders not been observed. This paper describes theoretical analysis effect longitudinal variation betatron tune on transverse instability. can be introduced by an RF quadrupole. In result, threshold could significantly increased when modulation frequency comparable with synchrotron tune.
Numerical calculations for the Spallation Neutron Source accumulator ring indicate that lattice resonances excited by space-charge potential can increase a mismatch significantly deforming beam distribution in phase space. Hence increased leads to enhanced envelope oscillations are driving 2:1 parametric resonance leading halo formation, even initially matched beams. We have observed this behavior $2{\ensuremath{\nu}}_{x}\ensuremath{-}2{\ensuremath{\nu}}_{y}=0$ and...