Patent Document ID: 5537207
Application ID: 08288254
Patent Status: 1

Claim One:
1. In a process for determining carbon black distribution and concentration in a carbon black-containing material, by: focusing pulsed laser beams on measuring points on a surface grid of the carbon black-containing material to produce plasmas thereat having characteristic radiations of analysis constituents contained in the carbon black-containing material; using measurements of the characteristic radiations taken by a detector assembly, which identifies the characteristic radiations by disbursing them spectrally in the form of spectral lines, calculating numerical ratios of radiation intensities of the characteristic radiations of selected analysis constituents; and, using these calculated numerical ratios, establishing concentration values of the analysis constituents; said process having the following steps: producing first and second plasmas with first and second laser pulses operating on the surface grid; taking respective first and second measurements with the detector assembly of spectral intensities of said first and second plasmas, each of the first and second measurements being carried out at a time delay (t.sub.v1, t.sub.v2) from actuation of the respective first and second laser pulse creating the first and second plasma being measured, the time delay (t.sub.v2) of the second measurement being of a substantially shorter duration than the time delay (t.sub.v1) of the first measurement; using the first measurement, determining intensities of spectral lines of carbon as a reference constituent (I.sub.C), and at least approximately all of the other analysis constituents (I.sub.A.n) of the surface, and from these, calculating intensity ratios (I.sub.A.n /I.sub.C) of each spectral-line intensity for each analysis constituent to a spectral-line intensity for the carbon as a reference constituent (I.sub.C); using the second measurement, determining intensities of spectral lines of reference constituent (I.sub.C,), and of at least one of the other analysis constituents (I.sub.A.n,) and from these calculating an intensity ratio; using calibration curves obtained by carrying out measurements like those of the first measurement, with a similar first time delay but on specimens of known compositions, determining from the intensity ratio values (I.sub.A.n /I.sub.C) calculated for the first measurement, concentration ratios (C.sub.A.n /C.sub.C) of substantially all analysis constituents in the surface and from these determining a value of concentration (C.sub.C) of the reference constituent (carbon), and of concentrations (C.sub.A.n) of individual analysis constituents; using at least one further calibration curve obtained by carrying out similar measurements like those of the second measurements, with a similar time delay but from specimens of known compositions, determining from the intensity ratio values calculated for the second measurement a value of the concentration ratio between carbon black (C.sub.R) and a particular analysis constituent (C.sub.A.n) and, using the previously determined magnitude of the concentration of the analysis constituent, deriving therefrom a magnitude of a carbon black concentration at the grid surface.