We compare to the probe method a spectroscopic method for determining in plasmas the electron distribution function (EDF) over a wide energy range. For a test of the radiative-collisional model we use to describe the plasma radiation, the measured vibrational distributions of N 2 (C-B) and N + 2 (B-X) were compared with calculated ones using our model and EDFs measured by Langmuir probes. From this comparison we obtain a value for the rate constant for vibrational relaxation at the walls. In a second step we invert the system of model equations for obtaining the EDF from measured line intensities. From the vibrational structure of the emission spectra of the nitrogen molecule the EDF is obtained in the energy range of 1.5-4.5 eV. From the relative intensities of the emission of nitrogen molecules and helium atoms the EDF for electron energies above 11 eV is derived. In the region between these ranges the EDF is interpolated. The results agree within the limits of the experimental errors with the EDF measured directly by the probe.

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Abstract. The mechanical properties of near-surface layers of corundum ceramics treated by high-power pulsed ion beam of carbon are investigated. The samples for investigation were prepared from corundum substrate, which is usually used in microelectronic. The ion treatment was carried out at the TEMP-4M facility under the following conditions: an accelerating voltage of 160-200 keV, the current density in the pulse varied within 15-85 A/cm 2 . It was found that ion irradiation changes the structure and properties of near-surface layers of corundum ceramics. At the same time, melting and erosion of the surface layer takes place. These processes are accompanied by the formation of a network of microcracks. Microcracks are propagated only by the depth of melting layer. The mechanical properties were measured using a NanoTest600 nanohardness testing instrument. It was found that the nanohardness depends of the treatment modes. At a current density of 15A/cm 2 , with an increase treatment dose, the nanohardness of the irradiated surface layer increases in comparison with the initial value before irradiation. At higher current densities, the nanohardness of irradiated ceramics decreases relatively to the initial value before irradiation. The dependences of nanohardness off the irradiation dose in this case have the view of a curves with a minimum at irradiation doses of 2.5•10 14 and 1.3•10 14 cm -2 , for current densities of 50 and 85 A/cm 2 , respectively.