Abstract: Laser ablation combined with spectrometric analysis is a good tool for determining the composition of heterogeneous materials. By measuring the depth of an ablation crater at a target of a heterogeneous material, it is possible to generate a compositional profile as a function of the depth. It is also possible to generate a 3 dimensional profile by depth profiling of a plurality of craters. The depth measurement is conducted in situ and in real time so that the evolution of composition as a function of the depth can be measured. An interferometric technique with a short coherence length light is one of the preferred embodiments for measuring the depth in situ and in real time.

Abstract: A method and apparatus for spectrochemical analysis of liquids, including molten metals, using laser-induced plasma spectroscopy. The apparatus preferably comprises a high power pulsed laser focused on the surface of a liquid stream flowing in a measurement cell, and an optical spectrometer-detector assembly, which receives, detects and analyzes the radiation emitted by the high temperature plasma thereby excited. The measurement cell, and optional pump, establish laminar flow of the liquid flow, thereby permitting the laser to repeatedly sample a fresh un-perturbed surface, while also ensuring that bubbles formed in the liquid are removed from the focal volume Preferably, a blower prevents aerosols and matter ejected from the sample responsive to the incident energy from interacting with subsequent laser pulses, and from accumulating on the optic.

Abstract: A method and apparatus for spectrochemical analysis of liquids, including molten materials, using laser-induced plasma spectroscopy. The apparatus preferably comprises a high power pulsed laser focused on the surface of a liquid stream flowing in a measurement cell, and an optical spectrometer-detector assembly, which receives, detects and analyzes the radiation emitted by the high temperature plasma thereby excited. The measurement cell, and optional pump, establish a steady flow of liquid, thereby permitting the laser to repeatedly sample a fresh unperturbed surface, representative of the liquid volume, while also ensuring that bubbles and waves formed in the liquid are removed from the focal volume. Gas (usually air) blown above the liquid prevents aerosols and matter ejected from the sample responsive to the incident energy from interacting with subsequent laser pulses, and from accumulating on the optics.

Abstract: An apparatus and a method are disclosed for use with Laser Induced Breakdown Spectroscopy (LIBS) systems that can be applied to the real time analysis of molten materials or liquid. Since it is difficult to prepare a surface representative of the bulk when dealing with high temperature molten material, the invention, in one aspect, uses a forced gas flow through a tube insertable inside the molten material to generate a bubble. The inner surface of the bubble is a representative of the composition of the material. LIBS performed on such a surface produces an accurate real time analysis of material, even when other processing of material, e.g., copper smelting, etc., is being conducted.

Abstract: A sample of heterogeneous material is analyzed by directing a mixed-wavelength laser pulse at the sample to produce a plasma. The mixed wavelength pulse contains both shorter and longer wavelength components. The composition of the material is determined from the emission spectrum of the plasma.

Abstract: Laser ablation combined with spectrometric analysis is a good tool for determining the composition of heterogeneous materials. By measuring the depth of an ablation crater at a target of a heterogeneous material, it is possible to generate a compositional profile as a function of the depth. It is also possible to generate a 3 dimensional profile by depth profiling of a plurality of craters. The depth measurement is conducted in situ and in real time so that the evolution of composition as a fucntion of the depth can be measured. An interferometric technique with a short coherence length light is one of the preferred embodiments for measuring the depth in situ and in real time.

Abstract: In a method of spectrochemical depth-profile analysis of heterogeneous materials, a first burst of ablation laser pulses in a first beam is directed at a sample to form an ablation crater. A second single pulse or burst of laser pulses in a second beam having a smaller width than said first beam is then directed at the bottom of the crater so as to create a plasma that emits radiation representative of a component in the sample without a significant contribution from the walls of the ablation crater. The intensity of radiation from the plasma is measured and the concentration of the selected component is determined from the intensity of the radiation. The depth at which the measurement is taken is then evaluated and the above steps repeated to determined the evolution of concentration of said selected component as a function of depth.

Abstract: In a method of spectrochemical depth-profile analysis of heterogeneous materials, a first burst of ablation laser pulses in a first beam is directed at a sample to form an ablation crater. A second single pulse or burst of laser pulses in a second beam having a smaller width than said first beam is then directed at the bottom of the crater so as to create a plasma that emits radiation representative of a component in the sample without a significant contribution from the walls of the ablation crater. The intensity of radiation from the plasma is measured and the concentration of the selected component is determined from the intensity of the radiation. The depth at which the measurement is taken is then evaluated and the above steps repeated to determined the evolution of concentration of said selected component as a function of depth.

Abstract: A method and apparatus for spectrochemical analysis of liquids, including molten materials, using laser-induced plasma spectroscopy. The apparatus preferably comprises a high power pulsed laser focused on the surface of a liquid stream flowing in a measurement cell, and an optical spectrometer-detector assembly, which receives, detects and analyzes the radiation emitted by the high temperature plasma thereby excited. The measurement cell, and optional pump, establish a steady flow of liquid, thereby permitting the laser to repeatedly sample a fresh un-perturbed surface, representative of the liquid volume, while also ensuring that bubbles and waves formed in the liquid are removed from the focal volume. Gas (usually air) blown above the liquid prevents aerosols and matter ejected from the sample responsive to the incident energy from interacting with subsequent laser pulses, and from accumulating on the optics.

Abstract: A method and apparatus for spectrochemical analysis of liquids, including molten metals, using laser-induced plasma spectroscopy. The apparatus preferably comprises a high power pulsed laser focused on the surface of a liquid stream flowing in a measurement cell, and an optical spectrometer-detector assembly, which receives, detects and analyzes the radiation emitted by the high temperature plasma thereby excited. The measurement cell, and optional pump, establish laminar flow of the liquid flow, thereby permitting the laser to repeatedly sample a fresh un-perturbed surface, while also ensuring that bubbles formed in the liquid are removed from the focal volume Preferably, a blower prevents aerosols and matter ejected from the sample responsive to the incident energy from interacting with subsequent laser pulses, and from accumulating on the optic.

Abstract: A sample of heterogeneous material is analyzed by directing a mixed-wavelength laser pulse at the sample to produce a plasma. The mixed wavelength pulse contains both shorter and longer wavelength components. The composition of the material is determined from the emission spectrum of the plasma.

Abstract: A method and apparatus is disclosed for enhanced laser-induced plasma spectroscopic analysis of unknown heterogeneous materials. The apparatus has high power pulsed lasers with their beams focused on the material, typically two colinear lasers providing two pulses in the ultraviolet and in the near infrared spectral area. The first laser pulse vaporizes a small volume at the surface of the material and produces a plasma which is subsequently enhanced by the second laser pulse. The optical emission of the plasma is analyzed with a colinear optical spectrometer. The pulsed spectrum is detected by a gated photodiode array detector or by an array of photomultipliers each individually positioned to detect a line emission representative of a given element present in the material. The combination of the two laser pulses, appropriately synchronized, provides a plasma emission that is significantly stronger than a single laser pulse of the combined energy of the two pulses.

Abstract: A method and apparatus for rapid in-situ spectroscopic analysis of unknown heterogeneous materials is disclosed. The apparatus uses a high power pulsed laser whose beam is focused on the material, typically a porous compound of unknown composition such as an amalgamated powder or a mineral sample. The pulsed laser beam vaporizes a small volume of the material and produces a plasma having an elemental composition which is representative of the material composition. The optical emission of the plasma is analyzed with an optical spectrometer. The pulsed spectrum is detected by a gated photodiode array detector or by an array of individually positioned photomultipliers, to detect a background emission and a line emission representative of a given element present in the material.

Abstract: A method and apparatus for rapid in-situ spectroscopic analysis of preselected components of homogeneous solid chemical compositions, especially pharmaceutical products. The apparatus comprises a high-power pulsed laser whose beam is focused on the material, typically a tablet or the powder prior to compaction into the tablet, which generally consists of an active ingredient (e.g. a drug) and a filler material (cellulose, glucose, lactose, etc.). The pulsed laser beam vaporizes a small volume of the pharmaceutical product and produces a plasma having an elemental composition which is representative of the pharmaceutical product. The atomic composition of the vaporized material is analyzed with an optical spectrometer.