QUAPEVA: Variable High Gradient Permanent Magnet Quadrupole

International audienceWe present the magnetic and the mechanical design of tunable high gradient permanent magnet (PM) quadrupoles. The tunable gradient of the so-called QUAPEVAS extends from 100T/m up to 200T/m. Seven of them with various lengths, ranging from 26mm up to 100mm, for different integrated quadrupole strengths were manufactured. The measured magnetic performance of these devices is also reported. These devices were successfully developed to transport laser plasma accelerated electron beam. Such applications have however less stringent multipole harmonic content constraints than diffraction limited Light sources. Trails for lowering the multipole harmonics will be discussed

Energy spread tuning of a laser-plasma accelerated electron beam in a magnetic chicane

International audienceLaser-plasma accelerators (LPA) deliver relativistic electron beams with high peak current and low emittance, with energies up to the GeV-level in only few centimetres. However, the divergence and the energy spread of these beams remain too large for potential light source applications. A magnetic transfer line can be used to manipulate the electron beam phase-space and select the transmitted energies with a slit located at its center. We will show that with a proper focusing optics along the line, one can tune the energy spread of the beam at a given energy without loss and produce undulator radiation with controlled bandwidth. We present analytic studies, numerical simulations and experimental results on the controled electron beam transport and application to undulator radiation with a control of the bandwidth

Energy spread tuning of a laser-plasma accelerated electron beam in a magnetic chicane

International audienceLaser-plasma accelerators (LPA) deliver relativistic electron beams with high peak current and low emittance, with energies up to the GeV-level in only few centimetres. However, the divergence and the energy spread of these beams remain too large for potential light source applications. A magnetic transfer line can be used to manipulate the electron beam phase-space and select the transmitted energies with a slit located at its center. We will show that with a proper focusing optics along the line, one can tune the energy spread of the beam at a given energy without loss and produce undulator radiation with controlled bandwidth. We present analytic studies, numerical simulations and experimental results on the controled electron beam transport and application to undulator radiation with a control of the bandwidth

Variable high gradient permanent magnet quadrupole (QUAPEVA)

International audienceDifferent applications such as laser plasma acceleration, colliders, and diffraction limited light sources require high gradient quadrupoles, with strength that can reach up to 200 T/m for a typical 10 mm bore diameter. We present here a permanent magnet based quadrupole (so-called QUAPEVA) composed of a Halbach ring and surrounded by four permanent magnet cylinders. Its design including magnetic simulation modeling enabling us to reach 201 T/m with a gradient variability of 45% and mechanical issues are reported. Magnetic measurements of seven systems of different lengths are presented and confirmed the theoretical expectations. The variation of the magnetic center while changing the gradient strength is ±10 μm. A triplet of QUAPEVA magnets is used to efficiently focus a beam with large energy spread and high divergence that is generated by a Laser Plasma Acceleration source for a free electron laser demonstration and has enabled us to perform beam based alignment and control the dispersion of the beam

FAB10: a user-oriented bandwidth-tunable extreme ultraviolet lightsource for investigations of femtosecond to attosecond dynamics in gas and condensed phases

International audienceWe present the commissioning of the FAB10 beamline (Femtosecond to Attosecond Beamline at 10 kHz repetition rate) that has been developped and operated in the last few years at the ATTOLab facility of Paris-Saclay University. Based on the high harmonic generation process, the beamline is dedicated to investigations of ultrafast dynamics in a broad variety of systems ranging from gas phase to condensed matter in pump-probe arrangements. Its design and operation has been strongly influenced by both the laser and the large scale instruments communities, which makes it unique in several aspects. In particular, it is possible to tune the extreme ultraviolet (XUV, 10–100 eV) bandwidth from 0.2 to 20 eV – with corresponding pulse duration from 30 to 0.3 femtoseconds (fs) – thanks to an original and fully automated XUV spectral filter with three operation modes. After a general overview of the beamline features, each of those operation modes is described, characterized and illustrated with commissioning experiments

Publisher Correction: Control of laser plasma accelerated electrons for light sources

The original version of this Article contained an error in the last sentence of the first paragraph of the Introduction and incorrectly read ‘A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime in equation 11, nx(n-β) x β: n the two times and beta the two times should be bold since they are vectorsin Eq. 12, β should be bold as well.’ The correct version is ‘A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime.’This has been corrected in both the PDF and HTML versions of the Article

Control of laser plasma accelerated electrons for light sources

Electron beam quality in accelerators is crucial for light source application. Here the authors demonstrate beam conditioning of laser plasma electrons thanks to a specific transport line enabling the control of divergence, energy, steering and dispersion and the application to observe undulator radiation

Tunable High Spatio-Spectral Purity Undulator Radiation from a Transported Laser Plasma Accelerated Electron Beam

International audienceUndulator based synchrotron light sources and Free Electron Lasers (FELs) are valuable modern probes of matter with high temporal and spatial resolution. Laser Plasma Accelerators (LPAs), delivering GeV electron beams in few centimeters, are good candidates for future compact light sources. However the barriers set by the large energy spread, divergence and shot-to-shot fluctuations require a specific transport line, to shape the electron beam phase space for achieving ultrashort undulator synchrotron radiation suitable for users and even for achieving FEL amplification. Proof-of-principle LPA based undulator emission, with strong electron focusing or transport, does not yet exhibit the full specific radiation properties. We report on the generation of undulator radiation with an LPA beam based manipulation in a dedicated transport line with versatile properties. After evidencing the specific spatio-spectral signature, we tune the resonant wavelength within 200–300 nm by modification of the electron beam energy and the undulator field. We achieve a wavelength stability of 2.6%. We demonstrate that we can control the spatio-spectral purity and spectral brightness by reducing the energy range inside the chicane. We have also observed the second harmonic emission of the undulator

Publisher Correction: Control of laser plasma accelerated electrons for light sources

The original version of this Article contained an error in the last sentence of the first paragraph of the Introduction and incorrectly read ‘A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime in equation 11, nx(n-β) x β: n the two times and beta the two times should be bold since they are vectorsin Eq. 12, β should be bold as well.’ The correct version is ‘A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime.’This has been corrected in both the PDF and HTML versions of the Article