Abstract: Multi-ordered spectral data is obtained from various known substances and is stored in a spectral library. The identification of an unknown material is accomplished by correlating the sample's multi-ordered spectrum against all or a portion of the spectrum in the library, and finding the closest match.

Abstract: The approximation of a spectral continuum by determining a plurality of minima in the spectral data; splitting the spectral data into a predetermined number of groups N; for each group of spectral data, determining major minima for the group, and calculating an average and a standard deviation for the determined major minima; determining a polynomial function that can be drawn through the major minima of all groups; for each group of spectral data, determining minor minima; calculating an average deviation (?N) between this polynomial function and the determined minor minima; reducing the number of groups, and repeating this process for the reduced number of groups until a minimum number of groups is reached. Then, the least ?N corresponding to an optimal number of groups Nopt is determined. The spectral data is split into Nopt groups; and a polynomial function that can be drawn through both the major minima and minor minima is determined for Nopt groups.

Abstract: The present invention approximates and automatically subtracts continuum backgrounds in laser-induced breakdown (LIBS) and Raman spectra measured by non-gated detectors. Significantly, reference spectra are not used to determine background positioning in the present invention.

Abstract: A resonance ionization imaging device (RIID) and method for imaging objects using the RIID are provided, the RIID system including a RIID cell containing an ionizable vapor including monoisotopic atoms or molecules, the cell being positioned to intercept scattered radiation of a resonance wavelength .lambda..sub.1 from the object which is to be detected or imaged, a laser source disposed to illuminate the RIID cell with laser radiation having a wavelength .lambda..sub.2 or wavelengths .lambda..sub.2, .lambda..sub.3 selected to ionize atoms in the cell that are in an excited state by virtue of having absorbed the scattered resonance laser radiation, and a luminescent screen at the back surface of the RIID cell which presents an image of the number and position of charged particles present in the RIID cell as a result of the ionization of the excited state atoms.

Abstract: Raman spectroscopy uses a resonance ionization detector. In particular, a first laser source is provided for application of laser energy to a sample cell. A second laser source provides energy to the ionization detector, which ionization detector includes metal vapor having at least three energy states or levels. The laser from the second laser source has a frequency such that it will promote the metal vapor from one of its levels to a higher level, whereas the first laser source is tunable such that upon Raman scatter from the sample cell promoting the metal vapor as well, the metal atoms will be ionized and the ionization detector will detect the scatter from the sample material. The scatter from the sample cell is provided to the ionization detector by way of an optical coupler such as a lens. The ionization detector may be a flame-type ionization detector, a metal vapor cell ionization detector, for a glow discharge tube (such as a hollow cathode lamp) ionization detector.

Abstract: A method and apparatus for scientific analysis of a sample under low temperature vacuum conditions uses a vacuum chamber with a conveyor belt disposed therein. One end of the conveyor belt is a cool end in thermal contact with the cold stage of a refrigerator, whereas the other end of the conveyor belt is a warm end spaced from the refrigerator. A septum allows injection of a sample into the vacuum chamber on top of the conveyor belt for spectroscopic or other analysis. The sample freezes on the conveyor belt at the cold end. One or more windows in the vacuum chamber housing allow spectroscopic analysis of the sample. Following the spectroscopic analysis, the conveyor belt may be moved such that the sample moves toward the warm end of the conveyor belt where upon it evaporates, thereby cleaning the conveyor belt.

Abstract: A liquid-phase chromatography detector comprising a flow cell having an inlet tubular conduit for receiving a liquid chromatographic effluent and discharging it as a flowing columnar stream onto a vertically adjustable receiving surface spaced apart from and located vertically below and in close proximity to the discharge end of the tubular conduit; a receiver adapted to receive liquid overflowing from the receiving surface; an exit conduit for continuously removing liquid from the receiver; a light source for focussing fluorescence-producing light pulses on the flowing columnar stream as it passes from the outlet of the conduit to the receiving surface and a fluorescence detector to detect the produced fluorescence; a source of light pulse for producing acoustic waves in the columnar stream as it passes from the conduit outlet to the receiving surface; and a piezoelectric transducer adapted to detect those waves; and a source of bias voltage applied to the inlet tubular conduit and adapted to produce ionizat