We report the development of a method for the measurement of electric fields in glow discharge plasmas, based on Stark spectroscopy of argon atoms. The method is based on laser excitation of transitions in atomic argon. The key feature of the method is that the electric field is determined by matching experimentally obtained absorption spectra to theoretically calculated spectra. The dependence of the positions of energy levels of argon atoms on the strength of the electric field was calculated by solving the Schrodinger equation for the argon atom. Measurements of Stark spectra were made in the sheath region of a glow discharge using laser optogalvanic spectroscopy. The wavelength of the laser radiation was tuned to the transitions 4s-->nf (n=7,8,ellipsis,14) of the argon atom. For n=11, the lower limit for electric field measurements was estimated to be 14 V/mm.
We created a test object of the linewidth with three different certified sizes. Relief structures of the test object are individual steps and protrusions, as well as pitch structures with trapezoidal profile, created by anisotropic etching of monosilicon. The orientation of the silicon surface coincides with the (1 0 0) crystallographic plane. The structures are located in two orthogonal directions. We present the results of the study of the individual relief elements (protrusions and steps) with the help of a scanning electron microscope (SEM) and an atomic-force microscope (AFM). The widths of the upper bases of the protrusions are in the 14-400 nm range. We performed a correlation analysis of the experimental results, which demonstrates the high quality of the created structures.
Results of investigations in the field of measurements of geometrical characteristics of the electron beam of a scanning electron microscope (SEM) are presented. Methods for determining the electron beam diameter are developed and tested on various microscopes. Besides, methods for obtaining the dependence of the electron beam diameter on the beam current, the energy of the primary electrons, and the focusing of the beam are also developed. Finally, method for determining the electron density distribution in the electron beam is proposed.
We observed an unusual/anomalous asymmetry of the HeI 667.8 nm spectral line profiles emitted from the peripheral regions of a current sheet plasma, which is characterized by high electron density gradients. This asymmetry can be explained only by assuming that, in the plane perpendicular to the current in the sheet, there is a strong low-frequency oscillatory electric field, which considerably exceeds the ion electric microfield. Our calculations show that this field seems to correspond to either a circularly or nearly-circularly polarized wave in the current sheet plasma.
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