SU1385049A1 - Method of determining quantitative content of composites - Google Patents

Abstract

The invention relates to methods for determining the quantitative composition of materials by absorption of gamma radiation. The purpose of the invention is to simplify the implementation of the method for three-component mixtures. The layer of the material under study is irradiated with radiation from two sources with different gamma quanta energies and the intensity of the transmitted radiation fluxes is measured. The gamma quanta energies of the sources are chosen so that the mass absorption coefficients for all three components are the same for the first energy and The energy mass absorption coefficients of the two components would be equal to each other and different from the mass absorption coefficient of the third component. The calibration graphs determine the surface density of the material and the concentration of the third component, and then the concentrations of the first and second components are calculated using these values and the thickness of the sample. i (L

Description

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four

WITH

The invention relates to methods for determining the quantitative composition of materials by absorption of gamma radiation.

The purpose of the invention is to simplify the implementation of the method for three-component mixtures;

The method is carried out by a test obuoM.

A layer of the studied material of a certain thickness is sequentially irradiated with radiation from two sources with different gamma-quanta energies and the intensity of the transmitted radiation is measured. The gamma-quantum energy sources are chosen in such a way that the first energy has the same mass absorption coefficients for all three components, and for the second energy the mass absorption coefficients of douh components are equal to each other and differ from the mass absorption coefficient of the third component. In this case, the absorption of the radiation by the test material is described as follows.

I01 01 source flows izlu

Where

cheni first and second sources

respectively;

I ,, are the detected radiation fluxes of the first and second sources, respectively, after the passage of a layer of material with a thickness d;

K, K ,. K 3 - the concentration of components in the mixture;

6 - surface density of the material;

fi P j 9 density of components

ju d - mass absorption coefficient of components at energy, equal to the energy of the first source; :

f JO is the mass absorption coefficient of the first two components at an energy equal to the energy of the second source ;.

| S - mass absorption coefficient of the third component at an energy equal to the energy of the second source.

Q

5 0 5

0

five

five

0

five

The first two equations are valid for the geometry of a narrow photon beam. If this condition is not strictly fulfilled, they must be replaced by equations of a general form (it is taken into account that Ig, 1e ,, fj, p, constant values):

I, f (&), li If (6, Kz),. where f and 1 are some functions.

From the previously constructed calibration graph, which is the dependence of the intensity of the beam of the transmitted radiation of the first source I, the OT-surface density of the material, the value of the material obtained in the experiment I, determines the surface density of the material 6. The curve from the calibration graph, which is a curve curve reflecting the dependence of the intensity of the transmitted beam of the second source I on the concentration of the third component K at different values of the surface density of the mother la, obtained according to e, those ksperimen- value I, and the found value of d is determined by the value of K j.

From the third and fourth equations above the above system of equations, the sample thickness d, the surface density of material 6, the end K of the density and the density of all three components, the concentrations of K, and Kj of the first two components are determined.

The method is implemented in determining the concentrations of diamond, graphite and a metal catalyst in three-component spectra obtained in the synthesis of diamonds.

An isotope is selected as the first source for which the mass absorption coefficients of diamond, graphite and catalyst metal are equal. As the second source is selected

Ain, for which the mass absorption coefficients of diamond and graphite are equal. Measurements are made of the intensity of the radiation fluxes that pass through the sinter layer during irradiation of isotopes with gamma radiation and

. The thickness of the cake is measured. Using the calibration graph, the density of the cake is determined on top of the nose number by the intensity of the transmitted radiation flux. Using the second calibration chart.

the magnitude of 6 and the magnitude of the intensity of the flux of the transmitted radiation of the Am isotope find the concentration of - the metal catalyst in the cake. Solving a system of two equations, find the concentrations of diamond and graphite. The measured height of the cake was 9.3 mm.

When the Cs and At isotopes were examined by gamma rays, the following data were recorded: I, 186 pulses / s, Ij 298 pulses / s. The surface density was 4 g / cm. The concentrations of diamond, graphite and catalyst metal were 34, 15.5 and 50.5%, respectively.

Claims (1)

Invention Formula The method of determining the quantitative composition of composite materials including sequential irradiation with five 0 The material is emitted from two sources with 15 different gamma-quanta energies, measuring the intensity of the transmitted radiation fluxes and determining the sample height, characterized in that, in order to simplify the implementation of the method for three-component mixtures, the gamma-quanta energy sources are chosen so that the energies of the same are the mass absorption coefficients of all three components, and for the second, only two components, graphically from the calibration curves obtained using the first and second sources, ate respectively the surface density of the material and the concentration of one of the components, and then use these values to determine the concentrations of the other two components calculated.