More than 50 years after the laser discovery, X-ray free electron lasers (FEL), the first powerful tuneable, short pulse lasers in the X-ray spectral range, are now blooming in the world, enabling new discoveries on the ultra-fast dynamics of excited systems and imaging. LUNEX5 demonstrator project aims at investigating paths towards advanced and compact FELs. Two strategies are adopted. The first one concerns the FEL line where seeding and echo harmonic generation are implemented together with compact cryogenic in-vacuum undulators. In the second one, the electron beam is no longer provided by a conventional linear accelerator but by a laser plasma process, while a necessary particular electron beam manipulation is required to handle the electron properties to enable FEL amplification.

One direction towards compact Free Electron Laser is to replace the conventional linac by a laser plasma driven beam, provided proper electron beam manipulation to handle the large values of the energy spread and of the divergence. Applying seeding techniques enable also to reduce the required undulator length. The rapidly developing LWFA are already able to generate synchrotron radiation. With an electron divergence of typically 1 mrad and an energy spread of the order of 1 % (or few), an adequate beam manipulation through the transport to the undulator is needed for FEL amplification. Electron beam transfer follows different steps with strong focusing variable strength permanent magnet quadrupoles, an energy demixing chicane with conventional dipoles, a second set of quadrupoles for further dedicated focusing in the undulator. A test experiment for the demonstration of FEL amplification with a LWFA is under preparation and progress on the equipment preparation and expected performance are described.

The aim of the Femto-Slicing project at SOLEIL is to generate 100 fs X-rays pulses on two beamlines, CRISTAL and TEMPO, for pump-probe experiments in the hard and soft X-rays regions. Two fs lasers are currently in operation on TEMPO and CRISTAL for pump-probe experiments on the ps time scale enabling time resolved photoemission and photodiffraction studies. The Femto-Slicing project is based on the fs laser of the CRISTAL beamline, which can be adjusted to deliver 3 mJ pulses of 30 fs duration at 2.5 kHz. The laser beam will be separated in three branches: one delivering about 2 mJ to the modulator Wiggler and the other ones delivering the remaining energy to the TEMPO and CRISTAL experiments. This layout will yield natural synchronization between IR laser pump and X-ray probe pulses, only affected by jitter associated with beam transport. In this paper, we present the current status of the Femto-Slicing project at SOLEIL, with particular emphasis on the expected performance, and the design and construction of the laser beam transport and the diagnostics implementation.

LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating the production of short, intense, and coherent pulses in the soft X-ray region. The project consists of a Free Electron Laser (FEL) line enabling the most advanced seeding configurations: High order Harmonic in Gas (HHG) seeding and Echo Enable Harmonic Generation (EEHG) with in-vacuum (potentially cryogenic) undulators of 15 and 30 mm period. Two accelerator types feed this FEL line : a 400 MeV Conventional Linear Accelerator (CLA) using superconducting cavities compatible with a future upgrade towards high repetition rate, for the investigations of the advanced FEL schemes; and a 0.4 1 GeV Laser Wake Field Accelerator (LWFA), to be qualified in view of FEL application, in the single spike or seeded regime. Two pilot user experiments for timeresolved studies of isolated species and solid state matter dynamics will take benefit of LUNEX5 FEL radiation and provide feedback of the performance of the different schemes under real user conditions.

LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating the production of short, intense, and coherent pulses in the soft x-ray region. The single Free Electron Laser (FEL) line fed either by a superconducting Linear Accelerator of 400MeV or a 0.4-1GeV Laser Wake Field Accelerator (LWFA) enables seeding (High order Harmonic in Gas seeding and Echo Enabled Harmonic Generation) for the advanced fourth generation source with the conventional accelerator, and single spike operation for the fifth generation source with the LWFA. Two pilot user experiments for time-resolved studies of isolated species and solid state matter will take benefit of LUNEX5 FEL.

Ultrafast dissociation following core-shell excitation into an antibonding orbital led to the early observation in HBr of atomic Auger lines associated to the decay of dissociated excited atoms. The purpose of this article is to review the very large variety of systems where such a situation has been encountered, extending from simple diatomic molecules toward more complex systems like polyatomics, clusters, or adsorbed molecules. Interestingly, this phenomenon has revealed an extremely rich and powerful tool for probing nuclear dynamics and its subtle interplay with electron relaxation occurring on a comparable time scale. Consequently this review covers a surprisingly large period, starting in 1986 and still ongoing. (C) 2012 Elsevier B.V. All rights reserved.

The objective of this work was to develop and characterize a poly(dimethylsiloxane) device with an integrated active cooling function able to carry out capillary electrophoresis separations. Polymer-based microdevices are indispensable to recent advances in biomedical analysis. In particular, they have been applied to many microfluidic platforms owing to their low cost, ease of fabrication, and versatility in preparing complex microstructures. However, when applied to capillary electrophoresis separations, polymer microfluidic structures present an inherent disadvantage compared to glass and Si structures; they have a lower thermal conductivity than glass and Si. Although miniaturized devices allow operation at high electric fields, they face separation efficiency limitations due to Joule heating. There is, therefore, a strong need of developing capillary electrophoresis microfluidic structures with active cooling in order to operate at a higher electric field and potentially increase separation efficiency in these microdevices. A poly(dimethylsiloxane)/glass hybrid microfluidic capillary electrophoresis system is presented, where Joule heating was minimized by using an integrated active cooling function. Two poly(dimethylsiloxane) slabs with embedded microfluidic structures were irreversibly sealed on both sides of a thin glass slide. The top poly(dimethylsiloxane) slab was used to carry out capillary electrophoresis separations, whereas the bottom poly(dimethylsiloxane) slab was employed to cool down the buffer solution used during the capillary electrophoresis separation. As demonstrated on current versus voltage plots and on capillary electrophoresis electropherograms, capillary electrophoresis separation was able to be operated at a higher electric field when using the cooling function. The cooling rate was adjustable by varying the flow rate and the initial temperature of the liquid flowing in the cooling microfluidic structure.

The ARC-EN-CIEL (Accelerator-Radiation for Enhanced Coherent Intense Extended Light) project proposes a suit of novel light sources for the scientific community. Three FEL sources (LEL1, LEL2 and LEL4) sources rely on High Gain Harmonic Generation (HGHG) radiation and their Non Linear Harmonics seeded with the High Order Harmonics generated in Gas (HHG). LEL1 will cover the 200-1.5 nm spectral range with 100-30 fs FWHM pulses at a few kHz and adjustable in polarisation. LEL2 will provide 10-0.6 nm radiation with planar polarisation, in 100-30 fs pulses at a few kHz repetition rate. LEL4 will cover the 2-0.2 nm range, with 50-30 fs pulses at 1 kHz. LEL3 is a FEL oscillator in the 40-8 nm range with a repetition rate of 4.5 MHz. These FEL sources will reach MW to GW of peak power. In addition, undulator radiation will provide 200 fs pulses with energies up to 20 keV. FEL calculations are presented. The ARC-EN-CIEL project is phased according to the required electron beam energy: in phase 1 (220 MeV), the radiation extends down to 30 nm; in phase 1’ (800 MeV) and phase 2 (1 GeV), the radiation reaches 1 nm. Phase 3 adds LEL3 and the Energy Recovery Linac loops at 1 GeV and 2 GeV, where undulators emit conventional synchrotron radiation above 20 keV from short period in vacuum undulators and softX rays are produced from variable polarisation undulators. The accelerator is based on superconducting technology to enable a high repetition rate. The use of plasma acceleration in the project is under investigation.

In this work, we developed a PDMS electrophoresis device able to carry out on-chip derivatization and quantification of amino acids (AAs) using naphthalene-2,3-dicarboxaldehyde (NDA) as a fluorogenic agent. A chemical modification of the PDMS surface was found compulsory to achieve the derivatization of AAs with NDA and a limit of detection (LOD) of 40nM was reached for glycine. Finally, we suggested the applicability of this microdevice for the analysis of real biological samples such as a rat hippocampus microdialysate.

The determination of fluid flows in silicon microchannels is important for the design of microfluidic systems. In this paper, experimental investigations on the characteristics of low fluid flows (few mu l h(-1)) in silicon trapezoidal microchannels (21 mu m in depth, length and width ranging from 200 to 440 mm and 58 to 267 mu m, respectively) are presented. The test-devices have been fabricated using micromachining technologies. A double KOH etching process has been used to achieve microchannels in (100)-oriented silicon wafers as well as deep in-plane cavities used for capillary connections. Silicon has been finally anodically bonded on Pyrex substrates. The experimental set-up, based on the measurement of a differential pressure and a liquid-air interface displacement in a gauged tube, is fully detailed in terms of fluidic connections and measurement principle. The experimental results are in good agreement with the Navier-Stokes theory, solved by a simple iterative method. However, finite element modelling has been used to study complex 3D problems that were found in the devices and the experimental set-up. Finally, we propose abacuses for three different channel cross-sections that may be used to easily compute the flow in a microchannel. (c) 2007 Elsevier B.V. All rights reserved.

Heteropolyacids (HPA) with Keggin structure were evaluated as homogeneous Bronsted acid catalysts in the reaction of rapeseed oil transesterification with methanol and ethanol at 358 K and atmospheric pressure. Rapeseed oil transesterification with ethanol over anhydrous Keggin HPAs leads to higher conversion level than H2SO4 compared at equivalent H+ concentration and H2O/H+ molar ratio. By contrast, Phosphoric acid, a quite weaker mineral acid, structurally close to H(3)PW(12)O40, is not operative under similar conditions. This demonstrates the advantages of strong Bronsted acids in vegetable oil transesterification with ethanol in mild conditions. It is worth noticing that differences in acid strength between anhydrous Keggin heteropolyacids, H3PW12O40, H4SiW12O40, H3PMo12O40, H4SiMo12O40, measured by calorimetry, did not correlate simply the catalytic activity. Indeed, the proton solvation with water molecule was shown to be a crucial parameter. Then, Mo samples exhibited higher activities due to their ability to lose crystallization water at lower temperatures compared to W samples. Finally, it was shown that higher transesterification rates were obtained with ethanol than methanol in presence of HPA. (C) 2007 Elsevier B.V. All rights reserved.

We have studied the ultrafast dissociation of the H2S molecule upon S 2p3/2-->6a1 inner-shell excitation by combining high-resolution resonant Auger spectroscopy and energy-selected Auger electron-ion coincidence measurements. Auger final states have been correlated to the different fragmentation pathways (S+, HS+, and H2S+ ions). As an original result, we evidence a three-step mechanism to describe the resonant production of S+: the Auger recombination in the HS* fragment is followed for the A 3Pi and c 1Pi states by the S++H fragmentation mechanism.

X-ray photoelectron spectroscopy and Auger spectroscopy studies of gas-phase hexamethyldisiloxane (HMDSO) are presented. The photodissociation of this molecule is studied using various experimental coincidence techniques. We compare the fragmentation pathways observed after core ionization followed by Auger decay and after valence double photoionization of the molecule. A strongly selective production of the doubly charged tetramethyldisiloxane ion is observed in the low binding-energy regions. Theoretical calculations are carried out to tentatively explain the stability of the produced dication.

A position sensitive detector (PSD) adapted to the technical and mechanical specifications of our angle and energy resolved electron-ion(s) coincidence experiments is described in this article. The device, whose principle is very similar to the one detailed by J. H. D. Eland [Meas. Sci. Technol. 5, 1501 (1994)], is composed by a set of microchannel plates and a delay line anode. The originality comes from the addition in front of the encoding surface of a ceramic disk covered by a resistive surface. The capacitive coupling between the anode and the resistive plane has the double advantage of eliminating the spatial modulations due to the lattice of the anode and also of sensitizing a greater number of electrodes, increasing thus considerably the accuracy of the position measurements. The tests carried out with a time to digital conversion module of 250 ps resolution showed that a spatial resolution better than 50μm and a dead time of 160 ns can be achieved. Typical images obtained with the help of the EPICEA and DELICIOUS coincidence setups are also shown.

To get further insight into the CH2BrCl site-selective fragmentation previously observed upon inner-shell ionization, we have performed high-resolution Br 3d and Cl 2p Auger and spin-orbit resolved Br 3d Auger spectra, and studied the dissociation properties of the CH2BrCl2+ dication formed at threshold by means of threshold electron pair-ion coincidence measurements. The key point is that the origin of site-specific bond breaking is found in the Auger decay itself, as it preferentially populates selected dication states. Whereas the predominance of the C-Br bond breaking is observed in both threshold and inner-shell studies, no signature of selective C-Cl rupture is reported for the dication formed at threshold.

Electrophoresis in capillary and microfluidic systems, used in analytical chemistry to separate charged species, are quite sensitive to surface phenomena in terms of separation performances. In order to improve theses performances, new surface functionalization techniques are required. There is a need for methods to provide fast and accurate quantification about surface charges at liquid/solid interfaces. We present a fast, simple, and low-cost technique for the measurement of the zeta-potential, via the modelization and the measurement of streaming currents. Due to the small channel cross section in microfluidic devices, the streaming current modelization is easier than the streaming potential measurement. The modelization combines microfluidic simulations based on the Navier-Stokes equation and charge repartition simulations based on the Poisson-Boltzmann equation. This method has been validated with square and circular cross section shape fused-silica capillaries and can be easily transposed to any lab-on-chip microsystems.

The electroosmotic flow created in zirconia-modified capillaries has been previously investigated. In this paper, we compared the electroosmotic data set with streaming current measurements and we related all these data through zeta-potential. Streaming current measurements give an excellent indication on the direction and the value of the electroosmotic mobility of an electrolyte/capillary system for a large set of experimental conditions: 2 < pH < 12, 0 < ACN < 80 %, 10(-4) M < [SO(2- )4 ] < 4 x 10(-2) M. A good correlation between zeta-potential from streaming current measurements and zeta-potential from electroosmotic mobility measurements was observed (r2 = 0.95). However, the values obtained from streaming current were always slightly lower than the one calculated from electroosmotic mobility (slope = 0.86, sigma = 0.06). In zirconia-coated capillaries the zeta-potential can be tuned from -50 to +100 mV depending on the composition of the electrolyte.

Electron analysis combined with ion mass spectrometry is shown to be a unique tool to understand fragmentation dynamics of core-excited molecules. This article describes in detail a new setup devoted to energy and angle correlations measurements between the emitted particles resulting from inner-shell ionization or excitation. The data collection system is based on a pair of position sensitive detectors mounted behind a double toroidal electron analyzer and a short time-of-flight ion spectrometer. Because all relevant information results in time measurements, a natural synchronization in the events recording is obtained. The optimized geometry for the ion extraction allows spatial focusing for the ion trajectories by means of inhomogeneous extraction fields while preserving the time focusing. The N2 molecule has been used for full characterization of the setup whereas the CO2 molecule illustrates the role of the intermediate resonant state in controlling the final dissociation pattern. The bending mode excitation is shown to emphasize the O+ production, and the ion kinetic energy distribution is rationalized through an impulsive model.