We present the results of employing the alpha-spectrometry method to determine the characteristics of porous materials used in targets for laser plasma experiments. It is shown that the energy spectrum of alpha-particles, after their passage through porous samples, allows one to determine the distribution of their path length in the foam skeleton. We describe the procedure of deriving such a distribution, excluding both the distribution broadening due to statistical nature of the alpha-particle interaction with an atomic structure (straggling) and hardware effects. The fractal analysis of micro-images is applied to the same porous surface samples that have been studied by alpha-spectrometry. The fractal dimension and size distribution of the number of the foam skeleton grains are obtained. Using the data obtained, a distribution of the total foam skeleton thickness along a chosen direction is constructed. It roughly coincides with the path length distribution of alpha-particles within a range of larger path lengths. It is concluded that the combined use of the alpha-spectrometry method and fractal analysis of images will make it possible to determine the size distribution of foam skeleton grains (or pores). The results can be used as initial data in theoretical studies on propagation of the laser and X-ray radiation in specific porous samples.

Results in some directions of the target technology for research on high energy density and laser fusion at the Russian Federal Nuclear Centre-All-Russia Research Institute of Experimental Physics for the last three years are presented. The results of development of optical and X-ray methods of characterization and manufacturing techniques of targets for studying the equation-of-state at high pressures and the condensed rare gas targets for the influence of pulse-repeated laser irradiation are given.

This paper presents a scheme of an x-ray spectrometer with exchangeable secondary targets and investigation of its characteristics. A high-voltage power source with a voltage up to 75 kV and x-ray tubes with power up to 2.5 kW were used in the spectrometer to generate the primary x-ray radiation. The exchangeable secondary targets made it possible to get monochromatic radiation with a rather high degree of the spectral contrast. The use of tubes with different anodes materials (chromium, tungsten and rhodium) and different secondary targets provides efficient performance for the analysis of a range of concentrations of elements with atomic numbers 13 < Z < 92. In this case, it was possible to optimize the sample analysis for definite groups of elements, reaching detection limits (DL) of 10(-6) g/g in aqueous solutions. According to the sensitivity (DL), this device can act as a spectrometer with total external reflection of the primary beam (TXRF spectrometer). However, its design is simpler, it has better optical efficiency, its adjustment is simple and convenient and it has a high operating efficiency. Besides, the design of the device makes it possible to perform simultaneously, if necessary, x-ray fluorescence and x-ray absorption analyses of a sample. Examples of the application of the device for the determination of heavy-metal content in the aqueous solutions and measurement of thickness of films are presented in this paper. Copyright (C) 2007 John Wiley & Sons, Ltd.

An investigation method of spatial distribution of separate chemical elements, contained in samples complex chemical composition, using an X-ray CCD-camera is considered. The camera records a fluorescence of the chemical elements of the sample, excited by a radiation of a static X-ray tube. An image is built at a CCD matrix with a pinhole camera. The CCD-camera operates in a regime of a multi-frame spectral recording of separate photons, in which it is possible to identify both the energy of the incident quanta, and the coordinate of the point of incidence in each frame. Analysis of the formed data array makes it possible to obtain the spatial distribution of the elements, contained in the sample discretely on Z (atomic number). Investigation results of the CCD-camera characteristics, algorithms of the computer software of the data processing, and examples of the obtained images are presented in the paper. It is shown that using this method it is possible to get distribution patterns of the chemical elements in the multi-component samples with the spatial distribution up to approximate to Z 15-20 mu m. (c) 2007 Elsevier B.V All rights reserved.

The technique of argon determination in glass microspheres used in experiences on laser fusion is stated. The technique is based on registration of a spectrum of characteristic radiation of argon atoms, excited by β-radiation of tritium, contained in a target, or X-ray radiation of an external source for targets without tritium. The calculated dependencies of power of characteristic radiation on geometrical parameters of microspheres and results of measurement of various targets are submitted.

Tentative results of studies dedicated to development of submicron films of ion-exchange materials for element separation and concentration in TXRF are presented. A technique to produce 0.1-l urn films was developed. Some sorption properties of such films were studied. Film characteristics were measured on the laboratory mock-up of a TXRF spectrometer.

X-ray mirrors and broadband Bragg monochromators with modulated spectral distribution of the primary beam are studied for potential use in x-ray fluorescence analysis. An artificial structure composed of W - C layers and a pyrolytic highly-oriented graphite are used in the capacity of a Bragg monochromator. Lower detection limits are obtained using TER broad-band monochromator spectrometers. For platinum, a detection limit of similar to i x 10(-10) g is obtained using a 1 kW x-ray tube under monoenergetic excitation conditions (MoKalpha line). The sensitivity of analysis of multielement samples can be increased by choosing an optimum energy of excitation under precise setting conditions of the Bragg monochromator.