Results 1 - 10 of 278008
Results 1 - 10 of 278008. Search took: 0.105 seconds
|Sort by: date | relevance|
[en] We have applied a coherent scattering microscopy (CSM)system to the analysis of aerial images for extreme ultra violet (EUV)masks. Measurements of aerial images for sub 22nm node were performed. Results for critical dimension (CD)measurements showed that reliable actinic CD measurements were possible even down to 12nm node using the CSM system. Detailed descriptions of the system and analysis procedures will be given together with the analysis results for line and space and contact hole patterns of EUV masks for various technology nodes
[en] The extreme ultraviolet (EUV) phase-shifting point diffraction interferometer (PS/PDI) was developed and implemented at Lawrence Berkeley National Laboratory to meet the significant measurement challenge of characterizing EUV projection lithography optics. The PS/PDI has been in continuous use and under ongoing development since 1996. Here we describe recent improvements made to the interferometer, and we summarize metrology results from state-of-the-art 10x-reduction EUV projection optics
[en] Tungsten is used as a plasma facing material in fusion devices and since large radiation power of partially ionized tungsten reduces plasma temperature and affects fusion performance, we need a spectroscopic model for tungsten ions in order to study tungsten behavior in plasma. We have constructed a collisional-radiative (CR) model for W27+ ions including 226 configurations with n ≤ 9 and l ≤ 5 for spectroscopic diagnostics. We newly include recombination processes in the model and this is the first result of extreme ultraviolet spectrum calculated for recombining plasma component. Calculated spectra in 40-70 angstroms range in ionizing and recombining plasma components show similar 3 strong lines and 1 line weak in recombining plasma component at 45-50 angstroms and many weak lines at 50-65 angstroms for both components. Recombination processes do not contribute much to the spectrum at around 60 angstroms for W27+ ion. Dielectronic satellite lines are also minor contribution to the spectrum of recombining plasma component. Dielectronic recombination (DR) rate coefficient from W28+ to W27+ ions is also calculated with the same atomic data in the CR model. We found that larger set of energy levels including many autoionizing states gave larger DR rate coefficients but our rate agree within factor 6 with other works at electron temperature around 1 keV in which W27+ and W28+ ions are usually observed in plasmas
[en] Complete text of publication follows. Attosecond light pulses (1 as 10-18 s) can nowadays be produced by high-harmonic generation (HHG) in the Extreme Ultraviolet (EUV). In this spectral range, optical systems are much more difficult to design than in the visible range, partly because of the absorption of materials. Several techniques were proposed to overcome the problem of attosecond pulse control after the high harmonic source, for example by using filters, plasmas or gas mediums. Multilayer aperiodic chirped mirrors, which efficiently reflect EUV radiation, were recently proposed in order to manipulate such pulses. But the possibility of phase control over large spectral bandwidth has not yet been demonstrated. We designed and manufactured three plane multilayer mirrors with optimized reflectivity and controlled spectral phase in the 35-55 eV range near 45 deg incidence. Their reflectivity was characterized on the Elettra Synchrotron and their spectral phase, on an attosecond pulse source at CEA SPAM, providing a full characterization of their spectral response. We report on the characterization of these mirrors and show how they affect the temporal profile of the attosecond pulses. Such pulses provided by the HHG process are intrinsically chirped. We demonstrate that they can be recompressed using our designed multilayer aperiodic mirrors. Until now attosecond pulse manipulation was restricted to some shaping functions mainly determined by the material of the used optical elements. In this presentation we also propose a more flexible way to shape the pulses giving relatively high intensities. A combination of two may provide us with an active attosecond pulse-shaper. It allows the realization of some simple functions as a tunable pulse compression, or the shaping of a single, double or multiple sub-100 as pulses, the properties of which can be set by simply turning the pulse-shaper. Acknowledgements. This work was supported by the ANR project 07-BLAN-0150. The multilayer fabrication have been carried out on CEMOX (Centrale d'Elaboration et de Metrologie des Optiques X).
[en] The fission spectrum uncertainty (variance covariance) matrix is needed in many nuclear data applications. Unfortunately, most modern evaluated data files, with the exception of JENDL3.3, do not include information on the fission spectrum uncertainly. In this paper, the fission spectrum relative uncertainty matrix derivation for the Watt fission spectrum is followed by a more general derivation utilizing some characteristics of any fission spectrum. In the second derivation, the Watt spectrum is used only for the calculation of sensitivity coefficients. (authors)
[en] Using a generalized version of double optical gating, we produced single isolated attosecond pulses with 2-mJ, 25-fs driving lasers. Temporal characterization revealed that the 160-as pulses are accompanied with very weak pre- and postpulses. The dependence of the extreme-ultraviolet spectrum on the carrier-envelope phase of the 25-fs laser exhibited a unique 2π periodicity, indicating the robustness of the subcycle gating.
[en] The light emission (LE) in the UV and visible (blue) range generated by a planar gas discharge system (PGDS) with a semiconductor cathode (SC) are studied. New light source offer high-intensity narrow-band emission at various UV and visible wavelengths (330 - 440 nm). Spectra in N2 is presented, as well as intensity vs pressure curves for the main peaks of the spectrum. The use of source offers several advantages: PGDS can be extremely efficient energy converters transforming and amplifying a relatively low-powered photon flux incident on the receiving surface of the SC into a flux of high-energy particles over extended areas, i.e. electron, ions, photons. Thus, extremely bright UV and visible sources can be built. LE characteristics of the space in the PGDS are complex, depending on the emitting medium and species. By using the IR light to excite the SC of the system, we have shown that the discharge light emission (DLE) of the device with the N2 in the gap can serve as an efficient source of the UV radiation if gas pressure and electric field are sufficiently high. This is realized due to the effect of the stabilisation of the spatially homogeneous mode of the discharge in a narrow gap with a large emitting area of SC. Special features of DLE render it highly promising for the development of sources with a large area of the emitting surface, high spatial uniformity of UV radiation, and fast dynamics of these devices. This low cost, high power light sources can provide an interesting alternative to conventional UV lamps
[en] A comparison of some integral cross-section values for several cross-section libraries in the SAND-II format is presented. The integral cross-section values are calculated with the aid of the spectrum functions for a Watt fission spectrum, a 1/E spectrum and a Maxwellian spectrum. The libraries which are considered here are CCC-112B, ENDF/B-IV, DETAN74, LAPENAS and CESNEF. These 5 cross-section libraries used have all the SAND-II format. Discrepancies between cross-sections in the different libraries are indicated but not discussed
[en] Cosmic EUV/x-ray spectroscopists, including both solar and astrophysical analysts, have a wide range of high-resolution and high-sensitivity tools in use and a number of new facilities in development for launch. As this bandpass requires placing the spectrometer beyond the Earth’s atmosphere, each mission represents a major investment by a national space agency such as NASA, ESA, or JAXA, and more typically a collaboration between two or three. In general justifying new mission requires an improvement in capabilities of at least an order of magnitude, but the sensitivity of these existing missions are already taxing existing atomic data quantity and accuracy. This roadmap reviews the existing missions, showing how in a number of areas atomic data limits the science that can be performed. The missions that will be launched in the coming Decade will without doubt require both more and improved measurements of wavelengths and rates, along with theoretical calculations of collisional and radiative cross sections for a wide range of processes. (roadmap)