Measurement of reflection coefficients of organic and non-organic media and materials in UV spectrum

Measurements of the diffuse reflection coefficients of organic and inorganic materials and media in solid, granular and liquid forms were made in the UV field of 230–400 nm. A single channel spectrometer with an integrating sphere was used. Relation between diffuse reflection coefficients and the structure and composition of the samples is discussed. These data allow us to estimate the prospect of machine vision systems application for the UV range in such areas as biology, geology, remote control of materials and media

Study of electronic properties of transition metals and alloys by positron annihilation spectroscopy

Section V. Equipment, Methods and Automation of Nuclear Experiments, Interaction of Nuclear Radiation with the Matter and Applications of Methods of Nuclear Physic

Study of electronic properties of transition metals and alloys by positron annihilation spectroscopy

Section V. Equipment, Methods and Automation of Nuclear Experiments, Interaction of Nuclear Radiation with the Matter and Applications of Methods of Nuclear Physic

Generation of a highly directional supercontinuum in the visible spectrum range

This paper presents the results of experimental studies on the formation conditions of a highly directional supercontinuum (SC) produced via filamentation of a femtosecond laser pulse in air. The laser beam had an energy of 8–15 mJ, radiation wavelength of 940 nm and pulse duration of 70 fs. A spherical mirror, with or without aberrations, was used to focus the laser beam. It is shown that a SC forms behind a visible filament through a step-by-step conversion of the spectral composition from long wavelength to short wavelength (to 350 nm). The radiation is most stable when it is generated in the presence of aberrations in the wave front of the laser beam. On the track section 35–135 cm from the filament, radiation propagates in the form of a spatially stable structure similar to a soliton with a transverse dimension ≤300 µm. In this case, the SC significantly differs from the conical off-axis emission that occurs in the aberration-free filament, in that it displays a divergence close to the diffraction limit, linear polarisation and a shorter-range wing of the spectrum. The infrared component of the SC has a duration 2.8-times shorter than the pulse duration of the initial laser beam

Generation of a highly directional supercontinuum in the visible spectrum range

This paper presents the results of experimental studies on the formation conditions of a highly directional supercontinuum (SC) produced via filamentation of a femtosecond laser pulse in air. The laser beam had an energy of 8–15 mJ, radiation wavelength of 940 nm and pulse duration of 70 fs. A spherical mirror, with or without aberrations, was used to focus the laser beam. It is shown that a SC forms behind a visible filament through a step-by-step conversion of the spectral composition from long wavelength to short wavelength (to 350 nm). The radiation is most stable when it is generated in the presence of aberrations in the wave front of the laser beam. On the track section 35–135 cm from the filament, radiation propagates in the form of a spatially stable structure similar to a soliton with a transverse dimension ≤300 µm. In this case, the SC significantly differs from the conical off-axis emission that occurs in the aberration-free filament, in that it displays a divergence close to the diffraction limit, linear polarisation and a shorter-range wing of the spectrum. The infrared component of the SC has a duration 2.8-times shorter than the pulse duration of the initial laser beam

Measurement of reflection coefficients of organic and non-organic media and materials in UV spectrum

Measurements of the diffuse reflection coefficients of organic and inorganic materials and media in solid, granular and liquid forms were made in the UV field of 230–400 nm. A single channel spectrometer with an integrating sphere was used. Relation between diffuse reflection coefficients and the structure and composition of the samples is discussed. These data allow us to estimate the prospect of machine vision systems application for the UV range in such areas as biology, geology, remote control of materials and media

Positronics and Nanotechnologies - Possibilities of Studying Nanoobjects in Materials and Nanomaterials by the Method of Positron-Annihilation Spectroscopy

The method of positron-annihilation spectroscopy is shown to be one of the most efficient methods for determining sizes of nanoobjects (vacancies, vacancy clusters); free volumes of pores, cavities, and hollows; and their concentrations and chemical composition at the point of annihilation in porous systems and some defective materials (and generally in a lot of technologically important materials and nanomaterials). Experimental investigations of nanodefects in porous silicon, silicon, and quartz single crystals irradiated with protons and in quartz powders are briefly reviewed.JRC.F.5-Safety of present nuclear reactor