X-ray microscopy of living multicellular organisms with the Prague Asterix Iodine Laser System

Soft X-ray contact microscopy (SXCM) experiments have been performed using the Prague Asterix Iodine Laser System (PALS). Laser wavelength and pulse duration were λ = 1.314 μm and τ (FWHM) = 450 ps, respectively. Pulsed X rays were generated using teflon, gold, and molybdenum targets with laser intensities I ≥ 1014 W/cm2. Experiments have been performed on the nematodes Caenorhabditis elegans. Images were recorded on PMMA photo resists and analyzed using an atomic force microscope operating in contact mode. Our preliminary results indicate the suitability of the SXCM for multicellular specimens

Shock pressure induced by 0.44 [mu]m laser radiation on aluminum targets

Shock pressure generated in aluminum targets due to the interaction of 0.44 μm (3 ω of iodine laser) laser radiation has been studied. The laser intensity profile was smoothed using phase zone plates. Aluminum step targets were irradiated at an intensity I ≈ 1014 W/cm2. Shock velocity in the aluminum target was estimated by detecting the shock luminosity from the target rear using a streak camera to infer the shock pressure. Experimental results show a good agreement with the theoretical model based on the delocalized laser absorption approximation. In the present report, we explicitly discuss the importance of target thickness on the shock pressure scaling

Work-to-family enrichment and gender inequalities in eight European countries

All social roles have positive and rewarding as well as negative/problematic aspects. Research on the work–family interface has predominantly focused on conflicting roles. In contrast, this paper extends research on work–family enrichment (WFE), a positive aspect of work and gender differences in WFE in a cross-national context. Drawing upon social role theory and the culture sensitive theory on work–family enrichment, we examined gender differences in experiences of developmental WFE in a sample of service sector employees in eight European countries. In line with traditional gender roles, women reported more WFE than men. The relationship was moderated by both an objective and subjective measure of gender egalitarianism but in the opposite direction as hypothesized. The gender gap in WFE was larger in more gender-egalitarian countries, where women may be better able to transfer resources from the work domain to benefit their family role than in low egalitarian societies. National differences in labour market factors, family models and the public discourse on work–life balance mainly explain the unanticipated findings

Statistical investigations of the beam stability of the double-pass amplified zinc soft X-ray laser at 21.2 nm

At the Prague asterix laser system (PALS) of the Academy of Sciences of the Czech Republic the 1-TW asterix iodine laser is used as a pump source for soft X-ray laser experiments. The prepulse technique was applied which is known to enhance the X-ray laser output at the J=0–1 transition dramatically. Since Zn slab targets were used the laser wavelength was 21.2 nm. A prepulse beam having 1.6 J was preceding the main pulse by 10 ns. The main and the prepulse beam are focused by two different optical systems separately. Implementing a half-cavity set-up for double-pass amplification using a Mo/Si multilayer mirror the X-ray laser output was 10 times stronger than at single pass amplification in a 3-cm long plasma. Double-pass amplification was observed to be most efficient when the pump pulse duration was at least 120 ps longer than the round trip time in the half-cavity. Under this fundamental condition the X-ray laser reached saturation in the double-pass regime containing 4 mJ energy what is proved to be enough for applications. In this contribution the X-ray laser features like divergence in two dimensions, the beam quality (symmetry), the pointing angle and the time-integrated output energy are investigated over more than 100 shots. To characterize the stability of the X-ray laser the shot distribution, the mean value and the standard deviation for these parameters are evaluated. For 18 shots in a series — achieved during one single day — the corresponding values are given and detailed chi-squared tests characterize the Zn X-ray laser as a robust tool suitable for applications. At PALS soft X-ray laser beam time can be reserved for external research groups

Study of the stability of beam characteristics of the neon-like Zn X-ray laser using a half cavity

At the Prague Asterix Laser System Center (PALS) the Asterix iodine laser delivering up to 700 J/0.5 ns is used as a pump source for X-ray laser experiments and applications. The prepulse technique was applied which is known to improve the neon-like X-ray laser output at the $J = 0 {-} 1$ transition dramatically. Since Zn slab targets were used the operating wavelength was 21.2 nm. A prepulse having up to 20 J precedes the main pulse by 10 ns. The main beam and the prepulse beam are focussed by two different optical systems separately and their foci are superimposed at the target surface. By implementing a half-cavity set-up for double-pass amplification using a Mo/Si multilayer mirror – which can be used for more than 100 shots – the X-ray laser output was more than 10 times stronger than at the single pass in a 30 mm long plasma. Double-pass amplification was observed to be most efficient when the pump pulse duration was at least 150 ps longer than the round trip time ($\approx 260$ ps) in the half-cavity. Under this fundamental condition the X-ray laser reached saturation in the double-pass regime containing approx. 4 mJ energy which has been proved to be enough for future applications. In this contribution, the X-ray laser features like divergence in two dimensions, the beam quality (symmetry), the pointing angle and the integrated intensity giving an estimation of the output energy are investigated over 110 shots. To characterize the stability of the X-ray laser the shot distribution, the mean value and the standard deviation for these parameters are evaluated. For 18 shots in a series – what was achievable during one day – the corresponding values are given, and a statistical analysis carrying out a chi-squared test characterize the Zn X-ray laser as a robust tool suitable for applications. In the future it is planned to allocate X-ray laser beam time to external research groups

Ablation of organic polymers by 46.9-nm-laser radiation

Includes bibliographical references (pages 034109-3).We report results of the exposure of poly(tetrafluoroethylene) -(PTFE), poly(methyl methacrylate)-(PMMA), and polyimide -(PI) to intense 46.9-nm-laser pulses of 1.2-ns-duration at fluences ranging from ~0.1 to ~10 J/cm2. The ablation rates were found to be similar for all three materials, ~80-90 nm/pulse at 1 J/cm2. The results suggest that the ablation of organic polymers induced by intense extreme ultraviolet laser radiation differs from that corresponding to irradiation with longer wavelengths

XUV-laser induced ablation of PMMA with nano-, pico-, and femtosecond pulses

Includes bibliographical references (page 932).For conventional wavelength (UV-vis-IR) lasers delivering radiation energy to the surface of materials, ablation thresholds, etch (ablation) rates, and the quality of ablated structures often differ dramatically between short (typically nanosecond) and ultrashort (typically femtosecond) pulses. Various very short-wavelength (λ < 100 nm) lasers, emitting pulses with durations ranging from ∼10 fs to ∼1 ns, have recently been placed into routine operation. This has facilitated the investigation of how ablation characteristics depend on the pulse duration in the XUV spectral region. Ablation of poly(methyl methacrylate) (PMMA) induced by three particular short-wavelength lasers emitting pulses of various durations, is reported in this contribution