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 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: 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: An improved electrode cleaning system for an electrochemical sensor is disclosed. The improved electrode cleaning system includes a flexible wiper blade which is biased against a flat wiping surface formed by electrodes having a flat detection surface and a collar placed around the electrodes to prevent particulates from depositing between the electrodes. The collar is secured to the sensor by a recessed screw which also serves as a common electrical ground. The flexible blade preferably has two wiping portions for alternately wiping the electrodes and the common ground screw.