Related papers: Wakefield effects of the bypass line in LCLS-II

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 RadiaBeam/SLAC dechirper, a structure consisting of pairs of flat, metallic, corrugated plates, %a corrugated structure in flat geometry, has been installed just upstream of the undulators in the Linac Coherent Light Source (LCLS). As a…

In free electron laser facilities, almost every kind of device will generate wakefield when an electron beam passes through it. Most of the wakefields are undesired and have a negative effect on the electron beam, which means a decrease of…

For LCLS-II we estimate the power of radiated wakefields generated in the SRF cavities (including the 3rd harmonic cavities) and in the end transitions. Much of this power will pass through and reflect in the strings of cryomodules that…

In previous work [1] general expressions, valid for arbitrary bunch lengths, were derived for the wakefields of corrugated structures with flat geometry, such as is used in the RadiaBeam/LCLS dechirper. However, the bunch at the end of…

We evaluate longitudinal resistive wakefields for cylindrical beam pipes numerically and compare the results with existing approximate formul\ae. We consider an ultra-relativistic bunch traversing a cylindrical, metallic tube for a model in…

In this article we derive longitudinal impedance and wake function for an undulator setup with arbitrary undulator parameter, taking into account a finite transverse size of the electron bunch. Earlier studies considered a line…

Besides the original seeded undulator line, in the Soft X-ray free-electron laser (SXFEL) user facility at Shanghai, a second undulator line based on self-amplified spontaneous emission is proposed to achieve 2 nm laser pulse with extremely…

Operating the SLAC/KEK DDS (Damped Detuned Structure) X-band linacs at high gradients (in excess of 70MV/m) has recently been found to be limited by the accelerator structures breaking down and as a consequence severe damage occurs to the…

The role of laser frequency chirps in the laser wakefield accelerator is examined. We show that in the linear regime, the evolution of the laser pulse length is affected by the frequency chirp, and that positive (negative) chirp compresses…

In damping the wakefield generated by an electron beam traversing several thousand X-band linacs in the NLC we utilise a Gaussian frequency distribution of dipole modes to force the modes to deconstructively interfere, supplemented with…

Dipole wakefields in NLC (Next Linear Collider) structures have been measured with ASSET [1] and well predicted by a circuit model [2]. However, the experimental technique is both time-consuming and expensive. Here, we report on kick factor…

The energy spread in laser-wakefield accelerators is primarily limited by the energy-chirp introduced during the injection and acceleration processes. Here we propose and demonstrate the use of longitudinal density tailoring to adapt the…

In the NLC project multiple bunches of electrons and positrons will be accelerated initially to a centre of mass of 500 GeV and later to 1 TeV or more. In the process of accelerating 192 bunches within a pulse train, wakefields are excited…

Earlier RDDS (Rounded Damped Detuned Structures) [1,2], designed, fabricated and tested at SLAC, in collaboration with KEK, have been shown to damp wakefields successfully. However, electrical breakdown has been found to occur in these…

Terahertz frequency wakefields can be excited by ultra-short relativistic electron bunches travelling through dielectric lined waveguide (DLW) structures. These wakefields can either accelerate a witness bunch with high gradient, or…

The AWAKE experiment aims to demonstrate preservation of injected electron beam quality during acceleration in proton-driven plasma waves. The short bunch duration required to correctly load the wakefield is challenging to meet with the…

In this paper, wakefields driven by a relativistic electron beam in a cold homogeneous plasma is studied using 2-D fluid simulation techniques. It has been shown that in the limit when the transverse size of a rigid beam is greater than the…

Beam energy compression via chicane magnets has been proved to be an effective method to reduce the slice energy spread of electron beams generated by laser wakefield accelerators (LWFAs). This technique has been widely adopted by leading…

We propose to use a frequency doubled pulse colliding with the driving pulse at an acute angle to trigger ionization injection in a laser wakefield accelerator. This scheme effectively reduces the duration that injection occurs, thus high…