US 5,798,832 A · Process and device for determining element compositions and concentrations

Abstract

The invention pertains to a process and a device for determining the composition and concentration of elements in material samples using laser-based plasma emission spectroscopy. The process comprises the following steps: a) transformation of a portion of the material sample (20) to be analysed to a plasma-like state (46) by means of a pulsed high-power laser (12) focussed on the material sample (20); b) spectral analysis of the radiation emitted by the plasma (46) using a spectrometer (26); c) measurement of the total emission spectrum (44) of the plasma (46) changing per laser pulse in one or more spectral ranges typical of the element, using a detector (40); and d) calculation of the composition and concentration of the elements based on the entire spectrum (44) of measured emissions, i.e. the sum of a number of measured individual spectra (42). The claimed device (10) comprises a high-power laser (12), a spectrometer (26) and at least one measuring head (14) with integrated radiation optics (22). The high-power laser (12) and the spectrometer (26) are geometrically and stereoscopically decoupled from the measuring head and are connected to each other via at least one waveguide.

Claims10

Dependent claims

A process for determining element compositions and concentrations of material samples, in particular for determining the concentration or the presence of precious metals in unsorted metal scrap, by means of laser-based plasma emission spectroscopy, said process comprising the following steps:

a) transforming a portion of the material sample (20) to be analyzed to a plasma-like state (46) by means of a pulsed high-energy laser (12) focused on the material sample (20), the plasma emitting radiation characteristic of the material sample;
b) performing spectral analysis of the radiation emitted by the plasma (46) using a spectrometer (26);
c) measuring the total emission spectrum (44) of the plasma (46) changing per laser pulse in one or more spectral ranges typical of the element, using a detector (40);
wherein the composition and concentration of the material samples are calculated in a further procedural step d) based on the entire spectrum (44) of measured emissions, said calculation being effected by integrating several individual measurements or spectra (42), the pulse to pulse variations of the individual spectra (42) being integrated during plasma formation, the individual measurements being integrated in the detector (40);
step a) being performed by positioning a measuring head (14) on the material sample (20);
the measuring head (14) comprising a casing (32) inside of which there is provided radiation optics (22) at a defined constant distance from an exit opening (38) of the casing (32), the focal point of the laser beam being in the plane of the exit opening;
the casing (32) including at least one movable spacer (34), said spacer (34)--in a first position thereof--partially projecting from the side of casing (32) which faces the sample (20) to be measured and--in a second position thereof--being completely inside the casing (32), said spacer (34)--in its second position--releasing a trigger means (38) for the laser source (12).

4 more elements

Dependencies are inferred from the claim text.

Process and device for determining element compositions and concentrations

Life of this patent

Process and device for determining element compositions and concentrations

Life of this patent

Abstract

Claims10