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We report on the measurement of spectral linewidth of a Ne-like Ar table-top capillary discharge laser. The linewidth was measured as a function of the gain medium length. Due to inhomogeneous character of the linewidth, saturation re-broadening is expected. However no such behavior was observed while the amplifier length was extended beyond saturation. This situation is compared with a numerical model, identifying that even a small amount of collisional broadening effectively homogenizes the line profile.

The LASERIX facility has restarted operation in the middle of the year 2010. Since then, important work has been achieved on the XUV sources performance, reliability and stability, which lead to the construction of two beamlines. The first one is based on transient collisional soft X-ray laser. In the second one, the high order harmonic generation process is used to convert infrared laser into coherent XUV radiations. Characteristics and some recent works on both of them will be presented. Besides, a complete setup for pump-probe experiments has been developed and successfully tested. Some examples involving this device and dealing with plasma opacity, radiobiology and nanomagnetism will be presented. We will conclude this paper by a discussion on how application experiments can be turned into valuable diagnostics for XUV sources.

The influence of temporal pump laser profile on the Soft X-ray laser (SXRL) efficiency is investigated in double grazing incidence pumping (DGRIP) transient collisional scheme. We have demonstrated a simple method that allows to produce and control one or several small prepulses and the ASE level of the pump laser beam by modifying the regenerative amplifier parameters. By changing the temporal structure of the pump beam we observed both an increase of the SXRL energy and an improvement of the target lifetime. Measurements made for different configurations are presented and discussed.

International audience; We report recent experimental progress in the characterization of the temporal coherence and related spectral linewidth of plasma-based soft X-ray lasers (SXRL). New measurements were carried out with two types of SXRLs pumped in the quasi-steady state (QSS) regime, in a capillary-discharge plasma and in a laser-produced plasma. We describe the main results obtained from both experiments and compare them to dedicated numerical simulations. We discuss the results in the context of the possibility to achieve XUV lasers with pulse duration below 1 picosecond.

It is shown how various exact non-parametric inferences based on order statistics in one or two random samples can be generalized to situations with progressive type-II censoring, which is a kind of evolutionary right censoring. Ordinary type-II right censoring is a special case of such progressive censoring. These inferences include confidence intervals for a given parent quantile, prediction intervals for a given order statistic of a future sample, and related two-sample inferences based on exceedance probabilities. The proposed inferences are valid for any parent distribution with continuous distribution function. The key result is that each observable uncensored order statistic that becomes available with progressive type-II censoring can be represented as a mixture with known weights of underlying ordinary order statistics. The importance of this mixture representation lies in that various properties of such observable order statistics can be deduced immediately from well-known properties of ordinary order statistics.

Objective: The aim of this study is to explore current and lifetime prevalence of obsessive compulsive disorders (OCD) in eating disorder (ED) subgroups and subtypes defined by the DSM-IV and to study the chronology of appearance of these disorders taking into account the role played by denutrition. Method: Current and lifetime prevalence were investigated using the Mini International Neuropsychiatric Interview (MINI) and the Yale–Brown Obsessive Compulsive Scale in a sample of 89 DSM-IV ED patients (58 AN and 31 BN) and 89 matched controls. Results: Current and lifetime prevalence of OCD in ED was significantly higher than in general population (15.7% and 19% vs. 0% and 1.1%, P

Research investigating the comorbidity between eating disorders and substance-use disorders have reported positive but contrasting results. The aim of this study was to further explore this association by studying patterns of consumption of the entire range of psychoactive substances (alcohol, specific drugs, prescribed psychotropics) in a large sample (N=271) of eating-disorder DSM-IV subtypes. Results show that subjects suffering from anorexia of the restrictive type show significantly less drug-consumption behaviors and alcohol abuse and/or dependence disorders than purging anorexic and bulimic subjects. No difference was found in the total consumption of psychotropics among the four groups of eating disorders. However, more than half of eating-disorder subjects are regular consumers of psychotropics. Among these regular consumers, bulimics self-prescribe and increase their doses of psychotropics significantly more than anorexics. Features of impulsivity that are associated with purging and bulimic behaviors could play a specific role in these patterns of comorbidity and account for such differences.

It is shown how the two treatments in a 2 × 2 crossover trial can be compared with respect to both mean response level and within-subject response variability. Various exact statistical inferences are described, including tests, confidence intervals, and certain decision rules to determine whether the target parameters are within given intervals of interest. These inferences are valid even with few subjects, and no distributional assumption is required about the between-subject variability. The inferences are easily implemented using available statistical software.

We present in this paper a laser-driven coherent EUV beamline resulting from the combination of a versatile high-order laser harmonic generator with a robust plasma-based EUV laser amplifier. Both devices can be used separetely or in synergy. Seeding of the plasma amplifier by a high-order harmonic beam leads to a strong improvement of the EUV laser beam divergence and uniformity. Moreover the system can be turned easily into a IR pump-XUV probe setup for plasma opacity probing. The possibility to generate two separate harmonic sources from the same gas cell offers the opportunity to explore EUV pump-EUV probe experiments.

X-ray interference microscopy diagnostics of a nanosecond-pulse pumped Al (Z=13) plasma are presented. A transient picosecond Ni-like Ag X-ray laser (13.9 nm) is used as the probe beam and a wavefront division bi-mirror interferometer is adopted as the diagnosis tool. From the fringe shifts, the two-dimensional plasma density profile at 1 ns after the peak of the heating pulse is deduced. Opposite fringe shifts during the plasma development are observed and possible explanations for this behavior are discussed. This study will contribute to the validation of 1D and 2D hydrodynamic codes as well as to the better understanding of the physics during the development of laser produced plasmas.

The accurate characterization of thermal electron transport and the determination of heating by suprathermal electrons in laser driven solid targets are both issues of great importance to the current experiments being performed at the National Ignition Facility, which aims to achieve thermonuclear fusion ignition using lasers. Ionization, induced by electronic heat conduction, can cause the opacity of a material to drop significantly once bound-free photoionization is no longer energetically possible. We show that this drop in opacity enables measurements of the transmission of extreme ultraviolet (EUV) laser pulses at 13.9 nm to act as a signature of the heating of thin (50 nm) iron layers with a 50-nm thick parylene-N (CH) overlay irradiated by 35-fs pulses at irradiance $3\ifmmode\times\else\texttimes\fi{}{10}^{16}$ Wcm${}^{\ensuremath{-}2}$. Comparing EUV transmission measurements at different times after irradiation to fluid code simulations shows that the target is instantaneously heated by hot electrons (with approximately 10$%$ of the laser energy), followed by thermal conduction with a flux limiter of $\ensuremath{\approx}$0.05.

International audience; We discuss the effects of particle correlations on the spectral broadening due to the radiator motion (Doppler broadening) for a Ni-like XUV laser line pumped in two different regimes (transient and quasi-steady state regimes) of collisional excitation. In a medium with gain, radiative transport effects modify the observed profile and these modifications depend on the homogeneous or inhomogeneous nature of the intrinsic profile (be- fore amplification). The intrinsic line profile is usually described by a Voigt profile, which is the convolution of a Lorentzian profile due to the different homogeneous broadenings (electron collision-induced transitions and spon- taneous emission) and an inhomogeneous Gaussian profile due to Doppler shifts (due to the radiator motion in the free-particle limit). In this paper, it is shown that accounting for the correlations between particles modifies no- ticeably the radiator-motion broadened profiles, whatever the densities and temperatures values.

We present an experimental design to independently pump two soft X-ray laser media suitable for a seed-amplifier configuration. Both the seed and the amplifier target are operated in the TCE scheme utilizing the DGRIP technique with its intrinsic travelling wave excitation. Controlled injection of the seed X-ray laser into the amplifier medium is realized via a spherical XUV mirror. The experimental design is perfectly appropriate for benchmarking combined simulations of the ARWEN and DeepOne code. A first experiment at the PHELIX laser utilizing this scheme has been conducted, demonstrating signs of amplification and allowing for the direct measurement of the gain life time of a Ni-like silver SXRL.

We present in this paper some eort and prospects in order to turn a high intensity infrared laser facility into ainstallation providing external users with EUV coherent sources. Development of an harmonic beamline basedon quasiphase matching in capillary is presented. Plasma based soft x-ray laser scheme involving a plasma seederand an ampli“er is revisited with the aim of obtaining a robust fully coherent x-ray laser.Keywords: Soft x-ray laser, high order harmonics, Titanium-Sapphire lasers 1. INTRODUCTION Infrared laser facilities are already fantastic tools for the development of a large range of coherent XUV sources.In a second step they may be adapted to provide external users with beamtime for applications of these sources.If close collaborators are welcomed on sources under development, hosting external users requires sources withnot only acceptable performance but also a high level of reliability, availability and stability. This might be incontradiction with high performances or versatility. In this paper we present some eort and prospects to meetthis operationnal challenges in the case of laser based soft x-ray laser and high order harmonic generation.

We present a comprehensive theoretical analysis of the conditions that lead to absorption limited generation of high order harmonics in the case of low energy, long pulse duration infrared pump laser beams. With these pump laser beam parameters, tight focussing is necessary to reach the high laser intensity required for high non linear response at the atomic level. A limitation of phase-matching is then induced through the so-called Gouy phase shift. We explain how the positive atomic dispersion can compensate for that effect and derive the conditions for perfect phase matching. The influence of gas pressure, harmonic order, maximum laser intensity and focussing conditions are analysed. This work enables a precise separation between pure classical harmonic from possible XPA effects discussed in a recent experiment. It also constitutes a benchmarking of a code under development for quasi phase matching scheme investigation.

We present an alternative explanation of the high-order-harmonic-generation experimental results published recently by Seres et al. [Nature Phys. 6, 455 (2010)]. We show that the physical interpretation can be comprehensively done in the frame of classical theory of high-order harmonic generation without referring to a parametric effect in the XUV domain. The experimental conditions explored by Seres et al. indeed correspond to the case of long-pulse, low-infrared-energy laser beams for which tight focusing is necessary to reach the minimum intensity required for high atomic response. The positive atomic dispersion can compensate for the Gouy phase and explains the behavior of the experimental variation of the harmonic signal presented. We will show that our interpretation explains not only the global behavior of the curves but also the second-order variation of the signal as a function of experimental parameters.

Simultaneous confidence regions were recently derived for a large class of Bonferroni-based closed testing procedures (CTPs). This class and a very useful subclass of graphical procedures are described, and it is then shown how the direct approach of Guilbaud (2008) for such CTPs can be extended to cover also CTPs that are not Bonferroni based and that may utilize dependencies not utilized by Bonferroni-based procedures. The simultaneous confidence regions that can be derived through this extension include the known confidence bounds for the step-down version of one-sided Dunnett-type multiple comparisons versus a control in the balanced case. As a simple illustration of how the general results can be applied, similar bounds are derived for the unbalanced case. As a further, more elaborated, illustration, confidence bounds are derived for the Dunnett gatekeeping procedure of Xu et al. (2009) based on a primary and a secondary variable. In this procedure, primary rejections are made through an ordinary one-sided Dunnett procedure, and secondary rejections are restricted to treatment comparisons with primary rejections. It turns out that ordinary Dunnett-type confidence assertions can be made for all primary comparisons without rejections. Interestingly, informative confidence assertions can be made also for secondary comparisons without rejections, but only in case of matching primary rejections. The gatekeeping is thus naturally extended to confidence assertions.

The paper reports on the optimization of a table-top nickel-like molybdenum transient collisionally excited soft x-ray laser (SXRL) at 18.9 nm, performed by double-pulse single beam grazing incidence pumping (DGRIP) [1]. This scheme allows for the first time the full control of the pump laser parameters including the pre-pulse duration, optimally generating the SXRL amplifier under grazing incidence. The single beam geometry of collinear double-pulse propagation guarantees the ideal overlap of the pre- and main pulse from shot to shot, resulting in a more efficient, highly stable SXRL output. SXRL energies up to 2.2 µJ are obtained with a total pump energy less than 1 J for several hours at 10 Hz repetition rate without re-alignment under once optimized double pumping pulse parameters including energy ratio, time delay, pre- and main pulse duration and line focus width [1].

We review recent experimental work devoted to the characterization of the spectral profile and linewidth of two types of XUV lasers seeded by high-order harmonic radiation. The spectral properties were deduced from the measurement of the temporal coherence of the XUV laser pulse, using a variable pathlength interferometer. In this paper an optical-field ionization XUV laser developed at LOA laboratory (France), emitting at 32 nm, and a grazing incidence, and a transient XUV laser developed at Colorado State University (US), emitting at 18.9-nm, both operated in the injection-seeded mode, were investigated. We show that in both cases the measured temporal coherence length is slightly larger than when the lasers are operated in the amplified spontaneous emission (ASE) mode. The corresponding bandwidth is observed to be larger for the transient pumping system, which should more easily scale to sub-picosecond pulse durations.

The temporal coherence of seeded and unseeded GRIP transient Ni-like Mo X-ray laser emitting at 18.9nm was investigated by a wavefront division interferometer. The coherence time of the X-ray laser pulse is found to be of the order of 1.7ps in the ASE mode and slightly smaller when the amplifier is seeded with a high-order harmonic pulse. The spectral line width is subject to a gain narrowing when increasing the length of the plasma amplifier.

Un article est recemment paru dans le journal “Nature Physics” sous le nom “Laser-driven amplification of soft X-rays by parametric stimulated emission in neutral gases” [1]. Suite a l’observation experimentale de la croissance exponentielle du signal harmonique en fonction de la pression de gaz, les auteurs annoncent que seule une nouvelle theorie qu’ils appellent “XPA” pour (X-ray parametric amplification) permet d’expliquer le resultat. Or dans ce qui suit nous montrons qu’une etude detaillee de l’accord de phase dans le cadre de la theorie classique de la generation d’harmoniques d’ordres eleves permet de reproduire parfaitement et d’expliquer la croissance exponentielle du signal harmonique en fonction de la pression par l’augmentation de la longueur de coherence due a la dispersion atomique.

LASERIX is a french high-repetition rate laser facility devoted to the realisation of performed XUV laser sources and their use for applications. In this paper we describe the present status and the perspectives of use of LASERIX in the high-repetition rate configuration and the high-Energy one.

We present the results of an experiment performed at the NSF Center for EUV Science and Technology (Colorado State University) in which a wavefront division interferometer was used to investigate the temporal coherence of seeded and unseeded GRIP transient Mo X-ray laser emitting at 18.9 nm. We find that the coherence time of the X-ray laser pulse is of the order of 1.7 ps in the ASE mode and slightly smaller when the amplifier is seeded with a high-order harmonic pulse. The spectral linewidth is subject to a gain narrowing when increasing the length of the plasma amplifier. Such behaviour is consistent with another experiment performed with the OFI seeded Ni-like krypton X-ray laser, using the same interferometer.

The comparison of primary interest in a 2 × 2 crossover trial typically concerns the effect of the treatments, say A and B, on the mean response level. This article deals with another important aspect, namely the within-subject response variability under A and B. Differences in drug formulation and/or administration may lead to considerable differences in within-subject variability, whatever the difference in terms of mean level. Consideration of both these aspects may, therefore, be of considerable importance for the judgement of the treatments. It is shown that although there are no within-subject treatment replications, it is possible to make various exact inferences about the A/B ratio of within-subject variances and about the (A – B)-difference in mean level, simultaneously and marginally. These inferences are semiparametric in that no distributional assumption is made about the between-subject variability, whereas a normality assumption is used for the within-subject variability. The infere...

In their review of challenges to multiple testing in clinical trials, Hung and Wang (2010) considered the situation where a treatment is to be compared with an active comparator and the aim is to show non-inferiority and (if possible) superiority with respect to a primary and a secondary endpoint. This note extends their discussion of this particular situation, taking the sequentially rejective procedure they used for illustration as a starting point. Some alternative multiple testing procedures (MTPs) are considered, and corresponding simultaneous confidence regions are discussed that provide additional information "for free". The choice may then be based on the properties of these MTPs and corresponding confidence regions.

We have measured the near-field and far-field profiles (for λ=13.9 nm) as well as temporal coherence (for λ=18.9 nm) of injection-seeded and self-seeded solid-target amplifiers. The measurements were compared with model simulations.

Resume. We review recent experimental work devoted to the characterization of the spectral linewidth of three types of XUV lasers pumped by collisional excitation, and operated in either seeded or ASE modes. The spectral properties were deduced from the measurement of the temporal coherence of the XUV laser pulse, using a variable pathlength interferometer.

We demonstrated a $7.36$ nm Ni-like samarium soft-x-ray laser, pumped by $36$ J of a neodymium:glass chirped-pulse amplification laser. Double-pulse single-beam non-normal-incidence pumping was applied for efficient soft-x-ray laser generation. In this case, the applied technique included a single-optic focusing geometry for large beam diameters, a single-pass grating compressor, traveling-wave tuning capability, and an optimized high-energy laser double pulse. This scheme has the potential for even shorter-wavelength soft-x-ray laser pumping.

International audience; We report an observation of spectral gain narrowing of a high-order harmonic amplified by a soft-x-ray optical-field-ionized plasma. The temporal coherence and spectral linewidth of both the seeded and unseeded soft-x-ray lasers were experimentally measured using a varying-path-difference interferometer. The results showed that the high-order harmonic is subject to a strong spectral narrowing during its propagation in the plasma amplifier without rebroadening at saturation. This is in good agreement with a radiative transfer calculation including gain narrowing and saturation rebroadening.

International audience; We present what we believe to be the first measurement of the spectral properties of a soft x-ray laser seeded by a high-order harmonic beam. Using an interferometric method, the spectral profile of a seeded Ni-like krypton soft x-ray laser (32.8 nm) generated by optical field ionization has been experimentally determined, and the shortest possible pulse duration has been deduced. The source exhibits a Voigt spectral profile with an FWHM of 3.1±0.3 mÅ, leading to a Fourier-transform pulse duration of 4.7 ps. This value is comparable with the upper limit of the soft x-ray pulse duration determined by experimentally investigating the gain dynamics, from which we conclude that the source has reached the Fourier limit. The measured bandwidth is in good agreement with the predictions of a radiative transfer code, including gain line narrowing and saturation rebroadening.

The demonstration of a 7.36 nm Ni-like Sm soft x-ray laser pumped by 36 J of a Nd:glass chirped pulse amplification laser is presented. Double-pulse single-beam non-normal incidence pumping was applied for the efficient soft x-ray laser generation. Here the applied technique included a new single optic focusing geometry for large beam diameters, a single-pass grating compressor traveling-wave tuning capability and an optimized high energy laser double-pulse. This scheme has the potential for even shorter wavelength soft x-ray laser pumping.

This Letter reports on the optimization of a tabletop nickel-like molybdenum transient collisionally excited soft x-ray laser (SXRL) at 18.9 nm performed by a double-pulse single-beam grazing incidence pumping (DGRIP). This scheme allows for the first time, to our knowledge, the full control of the pump laser parameters including the pre-pulse duration optimally generating the SXRL amplifier under a grazing incidence. The single-beam geometry of the collinear double-pulse propagation guarantees the ideal overlap of the pre-pulse and main pulse from shot to shot resulting in a more efficient and highly stable SXRL output. SXRL energies up to 2.2 microJ are obtained with a total pump energy less than 1 J for several hours at a 10 Hz repetition rate without realignment under once optimized double pumping pulse parameters including energy ratio, time delay, pre-pulse and main pulse durations, and line focus width.

Proposed as satellite-based weapons during the 1980s, X-ray lasing was for a long time only achieved with enormous amounts of pump energy in either nuclear explosions or at kilojoule-class laser installations. During the last few years a tremendous development was achieved, most visible in the realisation of the FEL lasers at DESY and SLAC. As important for a wider applicability is the enormous reduction in pump energy for laser pumped plasma X-ray lasers, which now brings such devices into the range of applications for diagnostics and spectroscopy even in smaller laboratories. Main developments were the transient excitation scheme and the optimized pumping concepts. This paper concentrates on developments at the GSI Helmholtzcenter at Darmstadt aiming towards reliable X-ray laser sources in the range from 50 to several 100 eV. The main driving forces for the laser development at GSI are the possible application for the spectroscopy of Li-like ions in the storage ring ESR and the future storage ring NESR at FAIR, and the interest in novel plasma diagnostics.

To assess the role of growth hormone in fetal and infant growth, we analyzed the pretreatment data on 52 patients with a diagnosis of congenital growth hormone deficiency before 2 years of age, obtained from the Kabi Pharmacia International Growth Study. These infants had reduced birth-length standard deviation scores, an excess of birth weight relative to length, and progressive growth failure. We conclude that congenital growth hormone deficiency may cause impaired growth in utero and early infancy, and that growth hormone plays an important role in perinatal and infantile growth.

University Paris XI has developed a facility, which called LASERIX, intended to realize and use for applications transient collisional X-ray laser (XRL) beamlines at various wavelengths. It is based on the effect caused by beamlines of the ultra-intense infrared laser (100TW) rip into the high-density and high-temperature plasma, providing XUV laser pulses at alterable wavelengths of 7-40nm This soft-X laser source is widely used in biology, bio-medical, solid physics, plasma physics and many other domains. In order to make LASERIX a stable XUV laser source, the stable infrared beams are neededThe stability of the beams enhances the energy of X laser pulses. A system of detecting temperatures in different points of the laser chain and monitoring laser beam has been developed. For the second step, a new compressor has been built to produce auxiliary infrared laser beam which helps to improve the XUV pulse's energy. This article elaborates on the design and installation of them with the results discussed.

We present recent calculations performed with the Maxwell-Bloch COLAX code. We investigate several features of transient X-ray lasers pumped with grazing incidence geometry and operated either with or without seeding by a highorder harmonics pulse. We show that the spontaneous emission source term included in the code accounts well for the speckle patterns observed in near-field and far-field images of the amplification of spontaneous emission (ASE) beams. Our calculations confirm the predictions of a simpler model based on the properties of spatial and temporal coherence of the source. We study the role of varying the level of the harmonic pulse seeded in the X-ray laser plasma. We show that the amplification factor and the contrast with respect to the ASE background cannot be maximized simultaneously. Finally we describe a recent upgrade of the code in which a time-dependent description of the populations of the lasing states has been implemented. This more rigorous treatment allows us to investigate the small-scale temporal behaviour of seeded X-ray lasers. The new version of the COLAX code was recently tested and preliminary results will be presented.

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).

Stable and reliable operation of a nickel-like molybdenum transient collisional soft x-ray laser at 18.9 nm demonstrated and studied with a 10Hz Ti:sapphire laser system proves the suitability of the double-pulse non-normal incidence pumping geometry for table-top high repetition soft x-ray lasers and broadens the attractiveness of x-ray lasers as sources of coherent radiation for various applications. X-ray laser emission with pulse energies well above 1 μJ is obtained for several hours at 10Hz repetition-rate without re-alignment under optimized double pumping pulse parameters including energy ratio, time delay, pulse duration and line focus width.

Samples of plasmid DNA were irradiated with pulsed 18.9 nm radiation originating from a Mo X-ray laser (XRL) pumped in GRIP configuration at the LASERIX facility. Up to 21 000 pulses were delivered with a repetition rate of 10 Hz and average pulse energy of 200 nJ. Radiosensitization by two different platinum compounds (platinum terpyridine chloride (PtTC) and platinum nanoparticles) were investigated. SSB and DSB yields were measured using agarose gel electrophoresis. The occurrence of single and double strand breaks not present in controls having undergone the same treatment except for the XRL irradiation can be seen as a clear effect of the XRL irradiation. This confirms the role of direct effects in DNA damages as previously seen with low energy ions and electrons (1) (2). In addition we demonstrate a DNA breaks enhancement in the presence of platinum. No difference of enhancement was seen between these two radiosensitizers.

We characterize and control the harmonic emission in the spectral and spatial domains in order to define in which conditions the harmonic radiation can be a high-quality seed for soft x-ray and x-ray free-electron lasers. The length of the gas cell, where harmonics are generated, was optimized and the energy per pulse was determined in absolute value with a calibrated x-ray photodiode. The beam spatial profile was measured and, in some conditions, a very collimated beam with a half-angle divergence below 1 mrad could be obtained. We also show that increasing the intensity of the fundamental laser field leads to a considerable broadening of the bandwidth of the harmonic radiation, allowing us to cover a large spectral range. This effect is due to fundamental reshaping leading to an efficient phase matching of both short- and long-trajectory contributions.