No abstract available

[en] The laser has opened many new possibilities for plasma diagnostics. Intensive monochromatic light sources with higher precision and better time resolution have helped to improve such well-known techniques as interferometry and Schlieren method. At the same time, the range of applicability was extended into the infrared range. Due to the wave length dependence of the plasma diffraction index, the effects increase approximately lambda in interferometry and approximately lambda² in the Schlieren methods. The laser also helped to develop entirely new methods such as utilization of the Faraday effect in the electrons of a plasma in a magnetic field which allows the calculation of the product nsub(e) x B from the rotation of the polarization plane of monochromatic light with linear polarization. Here, too, the effect increases approximately lambda², and measurements have been carried out up to FIR (HCN,337 μ). The best diagnostic possibilities are offered by the Thomson scattering diagnostics. Electron and ion temperatures, electron densities, drift velocities, magnetic fields, wave propagation and dissipation can be measured by this method. (orig./AK)

[en] In this contribution measurements of time-of-flight (TOF) distributions of sputtered oxygen and carbon atoms obtained at a recently completed set-up are reported. Carbon atoms are released by bombardment of a graphite target by 6 keV argon ions. Atomic oxygen is sputtered from an oxidized titanium foil. In the case of sputtering of the titanium foil also titanium atoms and TiO molecules are detected. For resonant ionization of oxygen and carbon atoms a (2+1) single-color resonant ionization scheme is applied. TOF distributions are measured by delaying the ionizing laser pulse with respect to the ion pulse. The atomic oxygen density is estimated by a comparative measurement with a spectral close two-photon transition of xenon

[en] In this contribution, measurements of energy distributions of sputtered metal atoms (tungsten and aluminum), released from polycrystalline metal targets by bombardment with noble gas ions (argon and xenon, respectively) in the energy range between 150 and 250 eV, are reported. Laser induced fluorescence spectroscopy in connection with a special designed detection geometry is applied to study energy distributions of atoms ejected in selected emission angles. Normal and oblique incidence is investigated. In both cases, systematic changes of the measured energy distribution with the emission angle are observed. The experimental distributions are compared to simulations performed by the Monte-Carlo code TRIM.SP

[en] Short communication

[en] The paper discusses stationary and quasistationary scattering with in-face detection - a fairly new method of plasma diagnostics - and its advantages. The signal-to-noise ratio is the most important quantity in in-phase detection. It was measured as a function of electron density as well as of measuring time with different laser power as parameter. The parameters of the magnetic-field stabilized light arc are given, and the experimental arrangement is described. Also measured were electron density and electron temperature with magnetic induction and plasma pressure as parameters. (GG/AK)

[en] Fluctuations of electric fields are excited in an arc plasma synchronous to the irradiation with an argon ion laser. Satellites of the forbidden component of the 4471 A He line are observed. (Auth.)

[en] The measurements were performed with an argon laser yielding 8 watt at 4880 angstrom. The spectral distribution of scattered radiation measured around the laser line yielded a temperature of 1.5 eV for the excited atoms. (Auth.)

[en] A study of angular resolved velocity (energy) distributions of atoms sputtered from in situ prepared metal films is described in this contribution. The velocity resolution of the set-up is based on the pulsed laser-induced fluorescence technique, i.e., scanning the narrow bandwidth dye laser radiation over the Doppler broadened absorption profile of the sputtered particles. The arrangement of the vacuum vessel and fluorescence detection optics provides the means for an independent selection of the observed emission direction and the angle of incidence. A pulsed ion gun is applied to bombard the target with noble gas ions in the energy range between 200 and 500 eV. The target assembly allows the preparation of thin metal films by evaporation on optically polished glass substrates without break of the vacuum. We report on measurements obtained with this arrangement, i.e., the determination of energy distributions of sputtered aluminum atoms. The bombardment at both the normal and the oblique incidence of the ion beam are contained in the investigation. Pronounced anisotropic effects are observed in both cases. In the case of oblique bombardment the shape of the distributions reflects cascade effects as well as single collision properties. The energy distribution is approximated with the aid of an energy spectrum involving a superposition of exponential functions. The experimental results are compared with simulations obtained by the Monte Carlo code TRIM.SP

[en] The main advantages of stationary scattering diagnostics with gas lasers are shown, and the experimental arrangement for 90⁰ scattering experiments is described. The Thomson scattering profile of free electrons measured at the magnetic-field stabilized light arc hydrogen plasma with the 5,145 A line of an Ar ion laser was used to determine nsub(e) = 2 x 10¹⁵/cm^-3 and Tsub(e) = 1.6 eV. The blue 4,880 A line of the Ar ion laser near the Hβ line was then used to measure the scattering profile of excited H atoms and to calculate the Doppler temperature of T₂ approximately 1.5 eV. The authors explain why a continuous Ar ion laser influences the arc plasma and induces plasma fluctuations. (GG/AK)