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Physical Review Special Topics. Accelerators and Beams
ISSN 1098-4402 · American Physical Society · 2.400 artikel di indeks
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Artikel Jurnal
Beam-based model of broad-band impedance of the Diamond Light Source
In an electron storage ring, the interaction between a single-bunch beam and a vacuum chamber impedance affects the beam parameters, which can be measured rather precisely. So we can develop beam-based numerical models of longitudinal and transverse impedances. At the Diamond Light Source (DLS) to…
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Artikel Jurnal
High-Q operation of superconducting rf cavities: Potential impact of thermocurrents on the rf surface resistance
For many new accelerator applications, superconducting radio frequency systems are the enabling technology. In particular for CW applications, much effort is being expended to minimize the power dissipation (surface resistance) of niobium cavities. Starting in 2009, we suggested a means of reducing…
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Artikel Jurnal
First measurement and correction of nonlinear errors in the experimental insertions of the CERN Large Hadron Collider
Nonlinear magnetic errors in low-β insertions can contribute significantly to detuning with amplitude, linear and nonlinear chromaticity, and lead to degradation of dynamic aperture and beam lifetime. As such, the correction of nonlinear errors in the experimental insertions of colliders can be of…
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Artikel Jurnal
Compact representations of partially coherent undulator radiation suitable for wave propagation
Undulator radiation is partially coherent in the transverse plane, with the degree of coherence depending on the ratio of the electron beam phase space area (emittance) to the characteristic radiation wavelength λ. On the other hand, numerical codes used to predict x-ray beam line performance can…
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Artikel Jurnal
Application of disturbance observer-based control in low-level radio-frequency system in a compact energy recovery linac at KEK
A disturbance observer (DOB)-based control for a digital low-level radio-frequency (LLRF) system in a compact energy recovery linac (cERL) at KEK has been developed. The motivation for this control approach is to compensate for or suppress the disturbance signal in the rf system such as beam…
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Artikel Jurnal
Six-dimensional measurements of trains of high brightness electron bunches
Trains of ultrashort electron pulses with THz repetition rate, so-called comblike beams, are assuming an ever growing interest in plasma-based acceleration. In particle-driven plasma wakefield acceleration (PWFA), a train of driver bunches with separation of the order of plasma wavelength, i.e…
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Artikel Jurnal
Conceptual design of heavy ion beam compression using a wedge
Heavy ion beams are a useful tool for conducting high energy density physics (HEDP) experiments. Target heating can be enhanced by beam compression, because a shorter pulse diminishes hydrodynamic expansion during irradiation. A conceptual design is introduced to compress ∼100 MeV/u to ∼GeV/u heavy…
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Artikel Jurnal
Calculation of wakefields in 2D rectangular structures
We consider the calculation of electromagnetic fields generated by an electron bunch passing through a vacuum chamber structure that, in general, consists of an entry pipe, followed by some kind of transition or cavity, and ending in an exit pipe. We limit our study to structures having rectangular…
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Artikel Jurnal
Response matrices in strongly coupled storage rings with a radio-frequency system constraining the revolution time
We calculate the orbit response coefficients for an arbitrarily coupled storage ring subject to maintaining the orbit length constant due to the presence of a radio-frequency system.
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Artikel Jurnal
Very high resolution optical transition radiation imaging system: Comparison between simulation and experiment
Optical transition radiation (OTR) has become a commonly used method for 2D beam imaging measurements. In the Accelerator Test Facility 2 (ATF2) at KEK, beam sizes smaller than the OTR point spread function have been measured. Simulations of the OTR imaging system have been performed using the…
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Artikel Jurnal
Measurement of the magnetic material properties for ferrite-loaded cavities
Measurements of the magnetic characteristics of the Ferroxcube 8C12m ferrite material in the parameter range where the GSI heavy-ion synchrotron SIS 18 cavity resonator is operated are presented. At first, the permeability is determined as a function of frequency and bias magnetic field strength…
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Artikel Jurnal
Numerical studies of the behavior of ionized residual gas in an energy recovering linac
Next generation light sources such as energy recovering linacs (ERLs) are highly sensitive to instabilities due to ionized residual gas, which must be mitigated for successful operation. Vacuum pumps are insufficient for removal of the ions, as the ions are trapped by the beam’s electrical…
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Artikel Jurnal
Measurements of intrinsic emittance dependence on rf field for copper photocathodes
Radio-frequency (rf) photoinjectors are used to generate high-brightness electron beams for a wide range of applications. Because of their outstanding beam quality, they are particularly well-suited as sources for X-ray free-electron lasers (FELs). The beam emittance, which is significantly…
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Artikel Jurnal
Transverse profile imager for ultrabright electron beams
A transverse profile imager for ultrabright electron beams is presented, which overcomes resolution issues in present designs by observing the Scheimpflug imaging condition as well as the Snell-Descartes law of refraction in the scintillating crystal. Coherent optical transition radiation emitted…
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Artikel Jurnal
Rectilinear six-dimensional ionization cooling channel for a muon collider: A theoretical and numerical study
A muon collider requires a reduction of the six-dimensional emittance of the captured muon beam by several orders of magnitude. In this study, we describe a novel rectilinear cooling scheme that should meet this requirement. First, we present the conceptual design of our proposed scheme wherein we…
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Artikel Jurnal
Generation and measurement of velocity bunched ultrashort bunch of pC charge
In this paper, we discuss the velocity compression in a short rf linac of an electron bunch from a rf photoinjector operated in the blowout regime. Particle tracking simulations shows that with a beam charge of 2 pC an ultrashort bunch duration of 16 fs can be obtained at a tight longitudinal focus…
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Artikel Jurnal
Volume reflection and volume capture of ultrarelativistic particles in bent single crystals
The paper is devoted to the study of volume reflection and volume capture of high energy particles moving in planar fields of bent single crystals. The influence of volume capture on the process of volume reflection was considered analytically. Relations describing various distributions of…
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Artikel Jurnal
Soft x-ray self-seeding simulation methods and their application for the Linac Coherent Light Source
Self-seeding is a promising approach to significantly narrow the self-amplified spontaneous emission bandwidth of X-ray free-electron lasers (FELs) and hence to produce nearly transform-limited pulses. We study the radiation propagation through a grating monochromator installed at the Linac…
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Artikel Jurnal
Development of wide area environment accelerator operation and diagnostics method
Remote operation and diagnostic systems for particle accelerators have been developed for beam operation and maintenance in various situations. Even though fully remote experiments are not necessary, the remote diagnosis and maintenance of the accelerator is required. Considering remote-operation…
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Artikel Jurnal
Measuring the full transverse beam matrix using a single octupole
We propose a method to fully determine the transverse beam matrix using a simple setup consisting of two steering magnets, an octupole field and a screen. This works in principle for any multipole field, i.e., sextupole, octupole magnet or a radio frequency structure with a multipole field. We have…
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