Control of laser plasma accelerated electrons for light sources

Abstract

With gigaelectron-volts per centimetre energy gains and femtosecond electron beams, laser wakefield acceleration (LWFA) is a promising candidate for applications, such as ultrafast electron diffraction, multistaged colliders and radiation sources (betatron, compton, undulator, free electron laser). However, for some of these applications, the beam performance, for example, energy spread, divergence and shot-to-shot fluctuations, need a drastic improvement. Here, we show that, using a dedicated transport line, we can mitigate these initial weaknesses. We demonstrate that we can manipulate the beam longitudinal and transverse phase-space of the presently available LWFA beams. Indeed, we separately correct orbit mis-steerings and minimise dispersion thanks to specially designed variable strength quadrupoles, and select the useful energy range passing through a slit in a magnetic chicane. Therefore, this matched electron beam leads to the successful observation of undulator synchrotron radiation after an 8 m transport path. These results pave the way to applications demanding in terms of beam quality.

Interferometry for full temporal reconstruction of laser-plasma accelerator-based seeded free electron lasers

“…undulator radiation [35][36][37][38], significative achievements in terms of electron beam transport and manipulation [39] turned a corner, allowing for control of the synchrotron radiation spectral properties [40]. LPA-based FEL amplification is now within reach at least in the visible or ultra-violet range.…”

Robustness of a plasma acceleration based free electron laser

“…Those large orbit deviations and dispersion functions are usually corrected on conventionnal accelerators using Beam Based Alignment techniques [77]. In the specific framework of LPA, a specific beam pointing alignment compensation (BPAC) strategy can be applied [45]. Taking advantage of the motorised translations of the PMQs while monitoring the electron beam transverse shape on dedicated diagnostics, the quadrupole magnetic centers are tuned to independently minimise the transverse offsets as well as the dispersion functions.…”

“…The COXINEL line [43][44][45] (see Figure 1) relies on both the implementation of strong permanent magnet quadrupoles at the LPA exit and of the chromatic matching strategy. Following the LPA, a first set of strong permanent magnet quadrupoles enables indeed to refocus the highly divergent electron beam in order to minimize further chromatic effects in the transport line.…”

Water-Window X-Ray Pulses from a Laser-Plasma Driven Undulator

“…To date, only few experiments [42][43][44][45][46][47] have experimentally shown undulator radiation from a laser-plasma accelerated electron beam. Plasma-driven undulator radiation was generated first in the visible 42 at 740 nm with 7.5% FWHM bandwidth, using electron beams of 65 MeV energy and achieving a beam brightness of 6.5 × 10 16 photons/s/mrad 2 /mm 2 /0.1% bandwidth.…”