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International audience; In this paper we are giving a summary of the Apollon 10 PW facility laser design together with updated laser performance. The Apollon facility is currently under construction in France. The APOLLON laser system is a laser designed for delivering pulses as short as 15 fs (10⁻¹⁵ s) with an energy exceeding 150 Joules on target. The peak power delivered by this laser system will be 10 Petawatts (10¹⁶W). The Apollon laser system will be delivering 4 beams: one 10 PW beam (F1 beam 400 mm diameter), one 1 PW beam (F2 beam 140 mm diameter) and two additional probe beams (F3 and F4) at a repetition rate of 1 shot per minute. The laser system is based on Ti-sapphire amplifiers pumped by frequency doubled solid-state lasers. The repetition rate of the high energy part will be 1 shot per minute. The main beam at the output of the last amplifier will be split and dispatched to two experimental areas. The main laser beam is delivering 30 J before compression at a repetition rate of 1 shot per minute and we are currently increasing to get 100J. Design update and recent results of the Apollon 10 PW facility (PDF Download Available). Available from: https://www.researchgate.net/publication/316893870_Design_update_and_recent_results_of_the_Apollon_10_PW_facility [accessed Sep 12, 2017].

We report a recent experiment where the first hard x-ray beam line, X-ray Pump Probe (XPP) instrument using the SLAC National Accelerator Laboratory's Linac Coherent Light Source (LCLS) free electron laser, was used to heat thin foils to high energy densities ∼ 107 J/cm 3. An intense 9 keV, 60 fs (FWHM) duration beam with energy of 2 - 4 mJ at the XPP beam line was focused using beryllium lenses to an irradiance approaching 1016 Wcm -2. Targets of 0.5 - 3.5 μm thick foils of Ag and Cu were studied using a suite of diagnostics including Fourier Domain Interferometry, energy calorimetry and grating and crystal spectrometers. The experimental details and spectroscopic results from the campaign will be described. Preliminary results indicate that the target is heated relatively uniformly to a temperature lower than 20 eV. © 2011 SPIE.

We have analyzed the acceleration of laser-generated protons, produced at the rear surface of flat-cone targets irradiated by an ultra-intense (I∼5×1019 W/cm2) short (400 fs) laser pulse. We used different target sizes and shapes in order to find the optimum target layout. We find that for targets with a too narrow cone structure, the production of the hot electrons, driving the proton acceleration, is located prior to the accelerating rear surface of the target, resulting in a reduced maximum proton energy.

The acceleration of high-energy ion beams following the interaction of short (t 1018 W cm-2 μm2) laser pulses with solid targets is a field of research currently attracting high interest in the scientific community, due to some of the unique properties of these ion sources, promising routes toward the optimization of their energy content, and a number of possible, innovative applications in the scientific, technological and medical areas. Work on the characterization and development of these sources has progressed enormously over the past few years, thanks to the contribution of many groups worldwide. This paper will report some recent results, obtained in experiments carried out at the RAL and LULI laboratories, in which we investigated the ion acceleration mechanism, developed a technique to control the ion beam divergence and energy spectrum, and applied a proton radiography technique to investigate electric and magnetic field production following laser-matter interaction.

Conversion efficiencies of laser light into K x-ray radiation are used to characterize laser-solid interactions e.g. in measurements with back-lighter targets in Inertial Confinement Fusion research or in ultra short x-ray science where ultra short laser pulses are used to create x-rays for investigation of dynamic processes. In our measurements we observed high energy (few tens of keV) K x-ray radiation of element pairs created upon impact of a 1 ps, 100 J laser pulse on the target surface. The high-energy electrons created in this interaction ionise and excite the target material. We have used high purity alloy foils of Pd and Ag, as well as In and Sn and crystals of CsI and rare earth molybdates as target materials. Both constituents of these targets were simultaneously excited in one shot. The K x-ray radiation was dispersed and detected with the LCS (LULI Crystal Spectrometer), a Cauchois-type cylindrically bent transmission-crystal spectrometer. Measuring ratios in the x-ray spectra permits determination of relative conversion efficiencies for pairs of elements under identical laser-target interaction conditions.

This paper reviews recent experimental activity in the area of optimization, control, and application of laser-accelerated proton beams, carried out at the Rutherford Appleton Laboratory and the Laboratoire pour lpsilaUtilisation des Lasers Intenses 100 TW facility in France. In particular, experiments have investigated the role of the scale length at the rear of the plasma in reducing target-normal-sheath-acceleration acceleration efficiency. Results match with recent theoretical predictions and provide information in view of the feasibility of proton fast-ignition applications. Experiments aiming to control the divergence of the proton beams have investigated the use of a laser-triggered microlens, which employs laser-driven transient electric fields in cylindrical geometry, enabling to focus the emitted protons and select monochromatic beamlets out of the broad-spectrum beam. This approach could be advantageous in view of a variety of applications. The use of laser-driven protons as a particle probe for transient field detection has been developed and applied to a number of experimental conditions. Recent work in this area has focused on the detection of large-scale self-generated magnetic fields in laser-produced plasmas and the investigation of fields associated to the propagation of relativistic electron both on the surface and in the bulk of targets irradiated by high-power laser pulses.

An autonomous power generator unit including two micropower sources and their management IC has been fabricated: a RF power receiver and a 1 V miniature thermogenerator combined with a micropower DC/DC up-converter are combined with a 78% efficiency manager and charger, and a 5 nW discharge monitor to manage and store the harvested energy in a 30 above-IC deposited microbattery.

We present a novel technique for focusing and energy selection of high-current, MeV proton/ion beams. This method employs a hollow micro-cylinder that is irradiated at the outer wall by a high intensity, ultra-short laser pulse. The relativistic electrons produced are injected through the cylinder's wall, spread evenly on the inner wall surface of the cylinder, and initiate a hot plasma expansion. A transient radial electric field (107–1010 V/m) is associated with the expansion. The transient electrostatic field induces the focusing and the selection of a narrow band component out of the broadband poly-energetic energy spectrum of the protons generated from a separate laser irradiated thin foil target that are directed axially through the cylinder. The energy selection is tunable by changing the timing of the two laser pulses. Computer simulations carried out for similar parameters as used in the experiments explain the working of the micro-lens.

The control of parametric instabilities in large plasmas remains a challenge for the ICF program. Clearly, kinetic effects play an important role in the saturation mechanisms. Sub-picosecond Thomson analysis associated with short pulse interaction permits to explore these topics. A set of experiments have been performed in preformed, He plasmas using the 100-TW laser facility at LULI. The spectra of the electrostatic waves driven by stimulated Raman and Brillouin backscatterings generated in the 1.5 ps, ω laser interaction have been measured with 0.3 ps time-resolution by using a short Thomson probe. Additionally, space-resolved and k-resolved spectra have been obtained. The experiments show that the fastest instability -B-SRS- first develops in the rising part of the pump. The B-SBS-driven IAW grows more slowly. B-SRS then abruptly vanishes around the maximum of the pump, while the IAW can be detected tens of picoseconds after the pump, allowing direct measurement of the IAW damping. The EPW k-spectra show that the EPW dispersion relation significantly deviates from the standard one. They exhibit a k-feature which could be related to the presence of a hot electron population produced in the B-SRS saturation process.

The interaction of femtosecond laser pulses with SiO2 aerogel targets has been analyzed by x-ray spectroscopic methods. The use of an aerogel target with transparent grains makes it possible to considerably reduce the requirements on laser-pulse contrasts for which heating occurs without the formation of a preplasma. A nanoplasma with a density sevenfold higher than the solid-state density has been detected.

We demonstrate the influence of the prepulses and ASE of ultrashort pulses interacting with a solid target by addressing the direct comparison of the harmonic spectra generated by reflection onto a solid target with and without the introduction of a plasma mirror system. Harmonics up to the 20th of the fundamental of the Ti-Sa laser are clearly visible in a situation free from any plasma expansion.

International audience; The objective of the Apollon project is the generation of 10 PW peak power pulses of 15 fs at 1 shot/minute. In this paper the Apollon facility design, the technological challenges and the current progress of the project will be presented.

International audience; The recent development of ultrafast x-ray sources makes conceivable the analysis of subpicosecond transient structures in physics, biology and chemistry. This paper focuses on the laser-produced plasma technique. Mainly on the basis of the work done at LOA (France), we report the first experiments dedicated to the analysis of subpicosecond atomic motions on this time-scale.

Preliminary experiments using a long pulse laser generated X-ray source to back-light a short pulse laser heated thin foil have been performed at the Laboratoire pour l'Utilisation des Lasers Intenses (LULI) at Ecole Polytechnique in France. In these experiment, a 2 J , 300 ps , 532 nm laser was used to create the X-ray back-lighter. The primary diagnostic was a von Hamos spectrograph coupled to a 500 fs X-ray streak camera (TREX-VHS) developed at LLNL. This diagnostic combines high collection efficiency ( ≈10 −4 sr ) with fast temporal response ( ≈500 fs ), allowing resolution of extremely transient spectral variations. The TREX-VHS was used to determine the time history, intensity, and spectral content of the back-lighter. The second diagnostic, Fourier domain interferometry, provides information about the position of the critical density of the target and thus the expansion hydrodynamics, laying the ground work for the plasma characterization. The plasmas were determined to be moderately to strongly coupled, resulting in absorption measurements that provide insight into bound states under such conditions.

We use both a Fourier-transform-based analysis and time-retrieval calculations to get time-resolved measurements of the reflectivity and the phase shift of a chirped probe pulse interacting with a fs-laser-produced plasma by spectral interferometry in a single shot. We have devised a novel dual-quadrature Mach–Zehnder configuration in which wavefront division is used to obtain spatial fringes from the perturbed and unperturbed probe simultaneously. We demonstrate the capability of this technique with fully analyzed experimental data on the interaction of a femtosecond laser with C3H6 and C samples, showing 35-fs time resolution.

Using the technique of frequency-domain interferometry, we study the dynamics of ultrafast laser-produced plasmas at moderate laser irradiances. From the complex reflection coefficient measured with the two in-quadrature probe pulse polarizations, we determine the peak electron temperature during the pump laser pulse, the gradient scale length at critical density, the variation of the real and imaginary part of the dielectric constant of the plasma, and, using the Drude model, the collisionality of the plasma as a function of time and temperature. We find electron relaxation collision frequencies which depart from those predicted by the model of Lee and More (Phys. Fluids 1984;27:1273.) by no more than a factor of two.

Using the technique of frequency-domain interferometry, we demonstrate a new way of studying laser-induced breakdown at the surface of dielectric materials. A theoretical model based on electron production by multiphoton ionisation, inverse bremsstrahlung heating, and collisional ionisation is in quantitative agreement with both the detailed time variation of the dielectric constant and the pulse width variation of the fluence threshold. From the complex reflection coefficient measured with the two probe pulse polarisations in quadrature, we deduce the time variation of the dielectric constant of silica during breakdown.

A 256 × 256 IRCMOS array with a 35 μm pitch operating at 88 K and above 10 μm has been developed at LETI/LIR. High performance has been obtained using, on the one hand, a reduced dark current detector technology and, on the other, a new readout circuit architecture which maximises both charge handling capacity and responsivity. We have measured a NEDT of 13 mK at 88 K for a cutoff wavelength of 10.1 μm. A description of the array is given and the main electro-optical characteristics of the component are presented.

We have compared the acceleration of high-energy ions from the rear-surface of thin foils for various contrast conditions of the ultra-intense laser pulse irradiating the targets. The experiments were performed using the LULI 100 TW facility. We used Al targets of variable thicknesses and the laser pulse contrast ratio ahead of the main pulse was varied using either a fast Pockels cell or a single or double plasma mirror. The latter was installed at an intermediate field position, in between the focusing optics and the target, so that its effect was optimized. By improving with these two methods the laser pulse contrast, we have observed that we could significantly reduce the thickness of the target used for proton acceleration and at the same time increase both the cut-off energy of the accelerated protons and the energy conversion efficiency of the process.

This report describes an active solid target positioning device for driving plasma mirrors with high repetition rate ultra-high intensity lasers. The position of the solid target surface with respect to the laser focus is optically monitored and mechanically controlled on the nm scale to ensure reproducible interaction conditions for each shot at arbitrary repetition rate. We demonstrate the target capabilities by driving high-order harmonic generation from plasma mirrors produced on glass targets with a near-relativistic intensity few-cycle pulse laser system operating at 1 kHz. During experiments, residual target surface motion can be actively stabilized down to 47 nm (root mean square), which ensures sub-300-as relative temporal stability of the plasma mirror as a secondary source of coherent attosecond extreme ultraviolet radiation in pump-probe experiments.

We present here the latest results obtained with our high resolution broadband X-ray microscope. These results, both spatial and spectral, were obtained in several facilities such as Berlin's synchrotron Bessy II and LULI's laser ELFIE 100TW. The results show clearly the opportunity in high resolution microscopy that offer mirror based diagnostics.

LULI2000 is one of the most energetic laser facilities in Europe. Since its first shot in 2003, LULI2000 has been used by world-wide plasma scientists and has made an important contribution to laser plasma physics and Inertial Confinement Fusion studies. Composed of high-energy 3-beam neodymium glass chains, it delivers pulses in the ns regime at 1053 nm with an energy level up to 2 × 1 kJ. This multibeams facility is capable of combining kJ/ns pluses with high energy sub-ps ones.

We present a new ns fiber-based front-end for the LULI2000. This synthesized fiber front-end using an Arbitrary Waveform Generator for programmable pulse generation produce shaped long pulse from 100 ps to 20 ns at the µJ level and amplified at an energy of 200 mJ at 10 Hz

We report on the observation, by use of a sub-picosecond time-resolved phase-sensitive technique, of an electron gas pumped by an intense femtosecond laser pulse into the conduction band of three different wide-band-gap oxides. The free-carriers lifetime is measured to be two orders of magnitude longer in MgO and in Al2O3 than in SiO2.

The path to successful inertial confinement fusion (ICF) requires to observe and control the micro balloon deformations. This will be achieved using X-ray microscope among other diagnostics. A high resolution, high energy X-ray microscope involving state-of-the-art toroidal mirrors and multilayer coatings is described. Years of experiments and experience have led to a small-scale X-ray plasma imager that proves the feasibility of all the features required for a LMJ diagnostic: spatial resolution of 5μm, broad bandwidth, millimetric field of view (FOV). Using the feedback given by this diagnostic, a prototype for the Laser MegaJoule (LMJ) experiments has been designed. The experimental results of the first diagnostic and the concepts of the second are discussed.

A wireless, low power, 64-channel data acquisition system named WIMAGINE has been designed for ElectroCorticoGram (ECoG) recording. This system is based on a custom integrated circuit (ASIC) for amplification and digitization on 64 channels. It allows the RF transmission (in the MICS band) of 32 ECoG recording channels (among 64 channels available) sampled at 1 kHz per channel with a 12-bit resolution. The device is powered wirelessly through an inductive link at 13.56 MHz able to provide 100mW (30mA at 3.3V). This integration is a first step towards an implantable device for brain activity monitoring and Brain-Computer Interface (BCI) applications. The main features of the WIMAGINE platform and its architecture will be presented, as well as its performances and in vivo studies.

The objective of the "Institut de Lumie`re Extreme" consists in providing early in 2014 to the international scientific community an unique laser based facility delivering 150 J, 15 fs pulses at 1 shot per minute repetition rate allowing to investigate an unexplored domain of laser-matter interaction at 1023 - 1024 W/cm2 intensity level.

We report the first space-time observation of the ultrafast excitation and relaxation of an electron gas pumped into the conduction band of a wide band-gap insulator by an intense subpicosecond laser pulse. The experiment is based on a new phase-sensitive technique which allows a resolution of 120 fs in time and 5 \ensuremath{\mu}m in space. In crystalline and amorphous Si${\mathrm{O}}_{2}$, no evidence of gas expansion has been observed and a mean trapping time of 150 fs for the photogenerated carriers is measured.

Focusing a high intensity laser pulse, onto a thin foil target generates a plasma and energetic proton and ion beams from the target rear and front sides, propagating along the target normal. Such laser produced collimated and energetic protons beams are of high interest because of the wide range of applications: ion based fast ignitor schemes, probing of electromagnetic fields in plasma, isotopes production or hadron therapy. The 100 TW class laser system at the Advanced Laser Light Source facility, is used with an intensity close to 1019 W/cm2, to study protons acceleration with femtosecond laser pulses, ultra thin foil target and high contrast laser pulse ratio. To characterize the plasma expansion, we monitor it with an imaging technique using a femtosecond laser probe. In this configuration we were able to reach a proton critical energy of 12 MeV and to work with target foil thickness as small as 15 nm.

WIMAGINE is a wireless low power 64-channel data acquisition system designed for Electrocorticogram (ECoG) recording. The system is based on a custom integrated circuit (ASIC) for amplification and digitization and commercial components for RF transmission. It supports the RF transmission of 32 ECoG recording channels (among 64 channels available) sampled at 1 kHz per channel with a 12-bit resolution. The RF communications use the MICS band (Medical Implant Communication Service) at 402-405 Mhz and can achieve a data rate of 480 kbps with a bit-error rate of less than 1.5 × 10-10. The device is powered wirelessly through an inductive link at 13.56 MHz able to provide 100 mW (30 mA at 3.3 V). This integration is a first step towards an implantable device for BCI (Brain Computer Interface) studies and neural prosthetics. Here, we present the platform architecture, components and the first in vivo validations.

The transmission crystal spectrometer (TCS) is approved for taking data at the OMEGA-EP laser facility since 2009 and will be available for the OMEGA target chamber in 2010. TCS utilizes a Cauchois type cylindrically bent transmission crystal geometry with a source to crystal distance of 600 mm. Spectral images are recorded by image plates in four positions, one IP on the Rowland circle and three others at 200, 400, and 600 mm beyond the Rowland circle. An earlier version of TCS was used at LULI on experiments that determined the x-ray source size from spectral line broadening on one IP positioned behind the Rowland circle. TCS has recorded numerous backlighter spectra at EP for point projection radiography and for source size measurements. Hard x-ray source size can be determined from the source broadening of both K shell emission lines and from K absorption edges in the bremsstrahlung continuum, the latter being a new way to measure the spatial extent of the hard x-ray bremsstrahlung continuum.

We developed a compact plasma-based focusing optic that, in one step, increases the peak intensity of ultrahigh-intensity lasers without modifying the laser system itself. By using a plasma-based focusing optic with extremely small f-number (f/0.4), we have experimentally demonstrated a fivefold reduction of the focal spot size (from 4.4 to 0.9 microm), thus producing an at least eightfold enhancement of the laser light intensity. This innovative plasma-based optic opens the way for the study of high-energy-density and high-field science at intensities greater than presently available.

Collimated beams of energetic protons are produced by the interaction of short duration high intensity laser pulses with solid foils. This field has been the subject of many studies in the last decade. This interest is motivated by the wide range of application of such beams: ion based fast ignitor schemes, probing of electromagnetic fields in plasma, isotope production or hadron therapy. The recently commissioned 200 TW laser system (5 J, 25 fs, 1010 laser pulse contrast, 10 Hz repetition rate at 800 nm) at the Advanced Laser Light Source (ALLS) facility has been used to study proton acceleration with femtosecond laser pulses. The proton spectrum was characterized using a time of flight detector. Due to the high contrast of the laser pulse, foil targets as thin as 30 nm could be studied.

This paper presents the development of a low-power rail-to-rail SAR-ADC to be used in a medical implants. The first part discusses the principle schematic and the requirements for the neuronal implant application. Additionally, a full description of each part of this ADC SAR will be given. And finally the last part presents measurement results of a fabricated test chip in 0.35µM CMOS technology, with 86µW of power consumption, 12bits of resolution, and a speed of 24Ks/S.

In this paper we present the perspectives of the development of the XUV laser sources using High‐power laser facilities. We focus our paper on the present statuts of the LASERIX facility and especially its role in the development of the XUV laser sources considering the French “Institut de la Lumiere Extreme “(ILE) and the potential European project Extreme Light Infrastructure (ELI). Finally, we present one typical experiment performed in that context with the facility. It is dedicated to the fundamental study irradiation induced damage in DNA samples.

International audience; Attraction and fusion between co-propagating light beams, mutually coherent or not, can take place in nonlinear media as a result of the beam power modifying the refractive index of the medium. In the context of high-power light beams, induced modifications of the beam patterns could potentially impact many topics, including long-range laser propagation, the study of astrophysical colliding blast waves and inertial confinement fusion. Here, through experiments and simulations, we show that in a fully ionized plasma, which is a nonlinear medium, beam merging can take place for high-power and mutually incoherent beams that are initially separated by several beam diameters. This is in contrast to the usual assumption that this type of interaction is limited to beams separated by only one beam diameter. This effect, which is orders of magnitude more significant than Kerr-like nonlinearity in gases, demonstrates the importance of potential cross-talk amongst multiple beams in plasma.

The energy transfer from a long ($3.5\text{ }\mathrm{ps}$) pump pulse to a short ($400\text{ }\mathrm{fs}$) seed pulse due to stimulated Brillouin backscattering in the strong-coupling regime is investigated. The two pulses, both at the same wavelength of $1.057\text{ }\ensuremath{\mu}\mathrm{m}$ are quasicounterpropagating in a preformed underdense plasma. Relative amplification factors for the seed pulse of up to $32$ are obtained. The maximum obtained amplified energy is $60\text{ }\mathrm{mJ}$. Simulations are in agreement with the experimental results and suggest paths for further improvement of the amplification scheme.

In the laser‐plasma interaction process, for ultra‐high temporal contrast laser pulses, experimental measurements show that reducing the thickness of solid targets increases the laser‐to‐fast electrons energy conversion and the hot electron temperature. We have performed an experiment using the LULI 100 TW laser facility working in the chirped pulse amplification (CPA) mode at a wavelength λ0 = 1.057 μm, pulse duration 320 fs, laser spot size FWHM ∼6 μm and intensity ∼1×1018 W/cm2 in which the laser pulses were temporal‐contrast enhanced by the use of two plasma mirrors. Shots were performed on Si3N4 aluminum coated targets of thickness 30 nm to 500 nm. Spectra of the laser‐accelerated electrons were recorded with a spectrometer and are compared to PIC simulations performed with the CALDER code. The simulations allow an insight into the electron heating process during the laser‐matter interaction.

Beam optimization of laser‐accelerated protons is required to progress towards the development of applications, e.g. for fast ignition of fusion targets or dense plasma radiography. For this, three areas of improvement need to be pursued: increasing the maximum proton energy, enhancing the laser‐to‐protons conversion efficiency and reducing the beam divergence. Here we report on the reasoning which led us to envision limited size target to improve protons acceleration. We point out that pre plasma leakage from the target front side is a critical issue to allow efficient acceleration from such limited size targets and show that with very high temporal contrast laser pulses proton acceleration is improved in such targets.

The study of Kα line absorption by point-projection backlighting is presented for a laser-produced aluminum plasma at electronic densities below 5×10 21 cm -3 . The appearance of ionic species as a function of distance from the target is measured absolutely by the use of a knife edge as a spatial fiducial. These data are used to determine the gradient of the average charge as a function of space. A non-local-thermodynamic-equilibrium ionization model has been developed to determine temperature and densities consistent with this measure

Aluminum targets irradiated with intense (I ~ 1017W/cm2) 80 fs laser pulses are shown to emit strong K? lines in the kV spectral region. The analysis of the spectra indicates that suprathermal electrons play an important role in the laser energy deposition and transport. Hydrodynamic simulations taking into account hot electron transport are in quantitative agreement with the measurements. Based on these simulations, the duration of the suprathermal X-ray emission is shown to be comparable to the incident optical pulse.

Solid targets have been irradiated by 80 fs laser pulses at 1016 W/cm2 laser irradiance. A time-resolved Schlieren imaging technique has been developed to measure the effect of the laser amplified spontaneous emission (ASE). This diagnostic shows that the critical density is located at less than 1 μm away from the target surface in our experimental condition. This is in agreement with the X-ray spectra from solid aluminum target in the 0.7–0.9 nm wavelength range, which are characteristic of plasma with near solid electron density (Ne∼1023cm-3).

We present the application of short-pulse laser-driven hard x rays (>40 keV) for the direct density measurement of iron compressed by a laser-driven shock. By using an on-shot calibration of the spectral absorption, we are able to obtain line densities with 5%-10% precision, although the x-ray source is not monochromatic. We also discuss possibilities for increasing the precision, which would be an improvement for equation of state measurements.

In this paper we present the perspectives of the development of the XUV laser sources using High-power laser facilities. We focus our paper on the present statuts of the LASERIX facility and especially its role in the development of the XUV laser sources considering the French "Institut de la Lumiere Extreme" (ILE) and the potential European project Extreme Light Infrastructure (ELI).

We have used time and space resolved interferometry to measure the dynamics of a plasma expanding off the surface of a solid target. This allows accessing 1) the time- and space-resolved dynamics of the fast electrons (laser-accelerated from solids and expanding into vacuum from the rear target surface), and of the energy partition into bulk (cold) electrons and 2) the expansion velocity of an isochorically heated target, from which information about the heating process can be retrieved.

We present the application of short‐pulse laser‐driven hard x‐rays (>40 keV) for the direct density measurement of iron compressed by a laser‐driven shock. By using an on‐shot calibration of the line density, we are able to obtain line densities even though the x‐ray source is not monochromatic. The consequences for the line density measurement using a polychromatic source are discussed in detail, as well as the calibration method we propose to solve this problem.

Absorption and x‐ray emission results obtained with a 1 psec pulse incident on solid targets with an intensity between 1011 and 1016 W/cm2 are presented and discussed. For I 1015 W/cm2) an evaluation of the plasma parameters is obtained from high resolution keV spectra. Finally, the results are discussed in the light of 1‐D hydrodynamic simulations with time‐dependent atomic physics.

In this paper, the absolute calibration of photostimulable image plates (IPs) used as proton detectors is presented. The calibration is performed in a wide range of proton energies (0.5-20 MeV) by exposing simultaneously the IP and calibrated detectors (radiochromic films and solid state detector CR39) to a source of broadband laser-accelerated protons, which are spectrally resolved. The final result is a calibration curve that enables retrieving the proton number from the IP signal.

The first front-end CMOS co-integration based on the lateral SGMOSFET presented in this paper demonstrates the benefit of a co-integration approach for NEMS devices. Performance using this device is compared to that obtained with a standalone ASIC. The next step will consist of replacing equivalently the input transistor of the ASIC cascode structure by the SGMOSFET.

Through the time- and space-resolved interferometry of a short-pulse low-energy probe beam reflecting on the rear surface of a solid target irradiated on its front surface by a high-intensity laser, we have measured a very abrupt expansion of the target rear surface. The experiments were performed using the LULI 100-TW laser facility with a maximum of 10-20 J energy pulses of > 1019 W ldr cm-2 intensity, wavelength of 1.053 mum irradiating Al targets. The detected phase changes, with a few micrometers spatial resolution and picosecond temporal resolution, are interpreted as induced by the cloud of fast electrons having propagated through the target and expanding into vacuum. The measurements have been performed using a laser-pulse duration of 320 fs and a laser energy of 20 J, varying the target thickness from 25, 14, and 9.4 mum. The experimental phase measurements are compared to simulations obtained by post-processing simulation data, run with a 1-D adiabatic plasma-expansion code. The comparison allows one to access, for the first time, to the dynamics of the density and temperature of laser-accelerated fast electrons in solid targets and expanding into vacuum. The same technique also allows one to have information regarding the cold electrons and the energy-partition dynamics.