相关论文: Impedance of a Beam Tube with Small Corrugations
We consider the impedance of a structure with rectangular, periodic corrugations on two opposing sides of a rectangular beam tube. Using the method of field matching, we find the modes in such a structure. We then limit ourselves to the the…
The Linac Coherent Light Source (LCLS) project at SLAC uses a dense 15 GeV electron beam passing through a long undulator to generate extremely bright x-rays at 1.5 angstroms. The project requires electron bunches with a nominal peak…
The beam coupling impedances of small axisymmetric obstacles having a semi-elliptical cross section along the beam in the vacuum chamber of an accelerator are calculated at frequencies for which the wavelength is large compared to a typical…
The beam coupling impedances of small obstacles protruding inside the vacuum chamber of an accelerator are calculated analytically at frequencies for which the wavelength is large compared to a typical size of the obstacle. Simple formulas…
This paper presents the approximate analytical solutions to the longitudinal space charge (LSC) impedances of a round beam with uniform transverse distribution and sinusoidal line density modulations under two boundary conditions: (a)…
A general derivation of the beam coupling impedances produced by small discontinuities on the wall of the vacuum chamber of an accelerator is reviewed. A collection of analytical formulas for the impedances of small obstacles is presented.
One of the key sources of transverse impedance in the LHC has been the secondary graphite collimators that sit close to the beam at all energies. This limits the stable bunch intensity due to transverse coupled-bunch instabilities and…
The parameters for a 30 GeV test beam are outlined for use with an undulator in the FFTB tunnel where the LCLS will eventually be housed. It is proposed to use the SLAC linac and damping rings in their present mode of operation for PEP II…
This paper studies the space charge impedances of a rectangular beam inside a rectangular chamber, and the limiting case, e.g., a rectangular beam between parallel plates, respectively. The charged beam has uniform density in vertical…
We investigate the effect of wall roughness on the wakefield-induced energy variation in the undulator beam pipe of LCLS-II. We find that a wall roughness equivalent to an rms surface slope of 30 mr increases the total induced energy…
The generation of the ultra-bright beams required by modern accelerators and drivers of free-electron lasers (FELs) has generally relied on chicane-based bunch compressions that often result in the microbunching instability. Following…
Although we believe most of the results presented here are correct, they are correct only in the limit of negligible beam disruption, which is not the ILC case. Also, the paper needs a convincing treatment of beam pipe shielding effects,…
Different limitations on luminosity of linac-ring type colliders coming from beam dynamics issues are considered for the examples of the $ep$ options of the THERA and LinacXLHC proposals. It is shown that $L=1.3\times 10^{31}$ for THERA and…
A compact Inverse Compton Light Source (ICLS) design is presented, with flux and brilliance orders of magnitude beyond conventional laboratory-scale sources and other compact ICLS designs. This design utilizes the physics of inverse Compton…
Magnetic impurities affect the spectrum of excitations of a superconductor and thus influence its impedance. We concentrate on the dissipative part of the surface impedance. We investigate its dependence on frequency, the density and…
The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) will double its beam intensity for the needs of High Energy Physics frontier. In order to ensure coherent stability until the beams are put in collision, the transverse…
The Drive Beam Linac of the Compact Linear Collider (CLIC) has to accelerate an electron beam with 4.2 A up to 2.4 GeV in almost fully-loaded structures. The pulse contains about 70000 bunches, one in every second rf bucket, and has a…
Alignment of the ILC main linac will be more critical than for any currently existing accelerators due to its long length and the ultra low emittance required. There are several techniques for measuring the ILC reference network; in this…
Interest in highly-compressed electron beams has been increasing in recent times, driven by the study of non-linear and even non-perturbative aspects of QED [2]. The FACET-II [7] facility at SLAC is currently (at the time of writing) being…
Resistive-wall impedance usually constitutes a significant percentage of the total beamcoupling impedance budget of an accelerator. Reduction techniques often entail high electrical-conductivity coatings. This paper investigates the use of…