Instrumentation Laboratory

Thermo Jarrell Ash Corporation

Allied Corporation

Robert G Schleicher

Stanley B Smith, Jr

Bruce C Fitz-Patrick

David L Pfeil

Allan G Dennison, Jr

Jon N Waterman

George A McLean

Paul M Moran

Edward C Eldred

A spectroanalytical system with a plurality of radiation sources and structure defining an analysis region that includes means for thermally energizing a sample material to be analyzed. Analysis beam path defining structure includes means for passing a radiation beam from a radiation source along the analysis beam path through the analysis region for modification by sample material in the analysis region. Analysis structure includes radiation dispersing structure arranged to disperse radiation in the analysis beam path with a spectrum and a radiation sensor. First transducer structure moves the dispersing structure relative to the beam path to apply a selected portion of the radiation dispersed by the dispersing structure to the radiation sensor. Source selector structure is disposed in the analysis beam for selecting radiation from one of the radiation sources along the analysis beam path, second transducer structure is coupled to the source selector structure for directing radiation from a particular radiation source along the analysis beam path, and control structure coordinately operates the two transducer structures to apply a particular dispersed wavelength of radiation from the selected radiation source to the radiation sensor.

Spectroanalytical system

A spectroanalytical system includes entrance aperture defining structure for receiving radiation to be analyzed along a first path; collimating structure in the first path for providing collimated radiation along a second path; fixed refraction structure in the second path for spatially separating (refracting) radiation in the second path in a first direction as a function of wavelength; fixed echelle grating structure in the second path for spatially separating the refracted radiation as a function of wavelength in a second direction orthogonal to the first direction and directing the orthogonally dispersed radiation in a beam along a third path that does not pass through the first refraction structure; and two-dimensional array detector structure for detecting the beam of orthogonally refracted radiation.

Spectroanalytical systems

A spectroanalytical method includes the steps of exciting material to spectroemissive levels, dispersing radiation from the excited sample material into a spectrum, positionally locating a reference constituent of the excited material in the spectrum, the reference constituent having a known wavelength offset from an element of interest in the sample material to be analyzed, and then shifting the known wavelength offset by an essentially hysteresis free mechanism and making an analytical measurement at that wavelength offset position of radiation produced by a spectrum from sample material that has been excited to spectroemissive levels.

Method of emission spectroanalysis

Method and apparatus for automatically depositing predetermined reproducible amounts of nebulized samples into a furnace atomizer of an atomic absorption spectrophotometer, the atomizer being provided with an aperture, wherein a plurality of sample containers containing samples to be analyzed are arranged and successively transported on a sample supporting device, with the sample containers being open at their upper ends. The samples are aspirated from the containers via a suitable means and into a nebulizer-mixing chamber device wherein they are nebulized and mixed until such time that the nebulized sample achieves full equilibrium therein. A means is provided for depositing the nebulized and now equilibrated sample from the chamber device through the aperture into the furnace atomizer. The deposition of predetermined and reproducible amounts of nebulized samples is controlled by a means which, in a preferred embodiment, comprises a vacuum source in valved communication with the means for depositing the nebulized sample in a way that aerosol deposition is effected only during the time period when the vacuum source is shut off from the means for depositing the aerosol sample by shutting off the valve. In another preferred embodiment, the means for controlling the amount of aerosol sample being deposited comprises a fluidic switch in communication with the nebulizer-mixing chamber device on the one hand and with the means for depositing the sample on the other. Hence, sample deposition takes place only during the time period when such communication from the chamber device to the deposition means is effected by the fluidic switch.

Automatic sample deposition in flameless analysis

A highly accurate, rapid scanning monochromator type of spectroanalysis system employs a source of the plasma emission type, a filtering monochromator, and a resolving monochromator. Each monochromator has a dispersing element and the two dispersing elements are arranged to be moved simultaneously but at different rates such that the spectral order of radiation from the source as dispersed by the first dispersing element is different from the spectral order of radiation dispersed by the second dispersing element, together with selectively operable control means for moving the two dispersing elements simultaneously and at the same rate.

Dual monochromator type of spectroanalysis system

An induction plasma system includes a plasma chamber, a high frequency electrical coil that surrounds the chamber, and an oscillator for energizing the coil to establish a plasma maintaining condition in the chamber. The oscillator tank circuit includes the coil, and is tuned so that it is essentially at resonance when a plasma condition is established in the chamber. Ignition means is arranged for initiating a plasma condition, and is constructed such that insertion of the ignition means into the chamber in the absence of a plasma condition shifts the impedance condition in the chamber to essentially the same tuned condition that exists when a plasma condition is established in the plasma chamber, but without need to adjust any component of the tank circuit.

Growing community of inventors

Winchester, MA, United States of America

Robert G Schleicher