In this paper we illustrate the main features of a new scheme which aims at obtaining coherent radiation at very short wavelengths (down to 1.5
nm) by using the Harmonics of an intense laser, ...generated in a gas, as a seed to inject in a long undulator, either in the pure SASE or in the HGHG configuration. The unique spatial and temporal coherence properties of the High-Order Harmonics are then conserved, and the High Gain FEL amplifier system saturates up to the GW level. An experiment is here proposed, to be performed on the new compact LINAC-based source SCSS, currently under development in SPring-8.
The spectral characteristics of the emission in the 140-315 nm range from pulsed-periodic capacitive discharges in mixtures of water vapor and helium and argon are described. In the VUV the most ...intense bands have maxima at λ = 156.0, 180.3, and 186.0 nm, and in the region of 300–315 nm, at λ = 312.1 and 313.4 nm. The brightness of the emission from the capacitive discharge plasma is optimized with respect to the partial pressures of helium, argon, and water vapor. The electron kinetic coefficients of discharges in argon and water vapor mixtures are calculated for E/N = 1–1000 Td.
A XeCl dielectric barrier discharge under applied pulsed and sinusoidal voltage waveforms is simulated using a one dimensional drift diffusion model. In both waveforms, the light output depends not ...only on the gas mixture composition but also on the electrical parameters of the voltage waveform such as the frequency, the duty ratio...ctc. At the same amplitude of the voltage and the frequency, the UV output efficiency of the pulsed voltage is higher than the one of sine voltage. These results obtained in this paper allow to find out an appropriate power supply mode for a DBD excilamp.
As one of the first experiments at the free electron laser of the TESLA Test Facility (TTF) the Coulomb explosion of Xenon clusters irradiated with high intensity pulses at a wavelength of 98nm has ...been observed. Classical trajectory calculations have been performed in order to illuminate the energy absorption process. Comparison with typical parameters in the infrared regime shows that above barrier ionization is suppressed due to the fast oscillating field and thermionic ionization prevails.
Dissociative photoionization of Si(CH
3)Cl
3 and Si(CH
3)
2Cl
2 has been investigated with photoionization mass spectrometry (PIMS) and a synchrotron as source of vacuum ultraviolet (VUV) radiation. ...We determined appearance energies (AE) of the parent cations, Si(CH
3)Cl
3
+ and Si(CH
3)
2Cl
2
+, and various ionic fragments. The appearance energy of Si(CH
3)Cl
3
+ is 11.18
eV and that of Si(CH
3)
2Cl
2
+ is 10.41
eV, in agreement with measurements of the photoelectron spectrum. Molecular electronic calculations of structures and energies of the radical cations and various fragment cations are made with Gaussian-2 and Gaussian-3. Results of these calculations are applied to establish dissociative photoionization channels of Si(CH
3)Cl
3 and Si(CH
3)
2Cl
2 near the ionization threshold. A comparison of Si(CH
3)Cl
3 and Si(CH
3)
2Cl
2 provides insight and understanding of fragmentation processes on dissociative photoionization of gaseous chloromethylsilanes.
KrCl
* (
λ∼222 nm) and XeCl
* (
λ∼308 nm) excilamps pumped by continuous glow discharges in different discharge geometries are studied. It was shown that the efficiency of rare gas halide molecule ...fluorescence over 25% can be obtained in a high-voltage glow discharge and positive column of a normal glow discharge. Coaxial XeCl
* and KrCl
* excilamps with UV output up to 200 W are developed.
Treatment of poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) with vacuum ultraviolet (VUV) radiation from high pressures of helium in rotating dc arc plasmas was investigated. X-ray ...photoelectron spectroscopy (XPS) detected defluorination and appearance of the functional groups
(C=O, O-C=O and C-O) on the surface. Fourier transform infrared (FT-IR) spectroscopy showed the appearance of a band at 1884 cm
−1
indicating the formation of the carboxylic acid fluoride moiety, -(C=O)-F. Improvement in film wettability was observed
by contact angle measurements while SEM micrographs showed an increased amount of cracking on the surface with VUV exposure. Adhesion measurements of Cu sputter-coated onto the photo-modified surfaces resulted in failure within the fluoropolymer (cohesive failure) and not at the Cu-fluoropolymer
interface. Cohesive failure occurred with shorter treatment times than for VUV exposure downstream from low pressure Ar microwave plasmas.
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