Abstract: A gas detector device including a porous matrix barrier disposed between one or more gas sensors and an environment exterior to the gas detector device. The porous matrix barrier includes a coating disposed on a matrix member surface, the coating imparting at least one of hydrophobic or oleophobic characteristic to the matrix member surface.

Abstract: An apparatus and method for open-path gas detection. The apparatus includes a radiation source and first and second radiation detectors sensitive to radiation in first and second spectral bands. The long cut-off wavelength of the second spectral band is longer than the long cut-off wavelength of the first spectral band, and the short cut-off wavelength of the second spectral band is shorter than the short cut-off wavelength of the short spectral band, such that the second spectral band is wider than and completely overlaps the first spectral band. Radiation from the radiation source passes through the area to be checked for gas, and is partially absorbed if gas is present. The path between the radiation source and the first and second radiation detectors need not be enclosed, and may exceed 100 meters in length. A processor compares intensity signals from the radiation detectors with a threshold value, and generates an output signal indicating a presence of gas based on the comparison.

Abstract: An instrument that analyzes chemical properties of a specimen includes a probe that is used in place on the specimen for spectroscopic analysis. The probe has a probe body with a proximal end and a distal end, and a first optical fiber extends from the proximal to the distal ends. A temperature sensor is included in the probe body and is used so insure that the probe does not exceed a rated temperature limit or to monitor specimen temperature while, simultaneously, chemical composition information of the specimen is transmitted by the optical fiber. The probe can be inserted into a container holding the specimen and can yield both temperature and chemical composition information. The probe includes a plurality of metal coated fibers with the distal ends of the fibers positioned inside a bore in the probe. Braze material is placed on the probe near the bore and the braze material is then brazed to the metal coating on the ends of the fiber.

Abstract: An analyzer for analyzing chemical properties of a specimen using optical coupling and sensing, has a narrow band light source and an optical probe that is in contact with the specimen. Detectors are used for providing electrical outputs as a function of a parameter of the specimen, and an optical path couples light from the light source to the probe and also couples Raman scattered light from the specimen and Rayleigh scattered light from the specimen to separate detectors. An analyzer circuit is coupled to the detectors to provide outputs as a function of the electrical signals received, and one of the detectors is connected to a signal conditioning circuit for controlling the input of the light source and includes an asymmetric discrimination circuit configured to distinguish positive going fluctuations from negative going fluctuations in the output from the detector.

Abstract: An instrument that analyzes chemical properties of a specimen using optical sensing provides a laser source with an optical fiber channel that carries light from the source to a probe. The probe has a receiving optical fiber and has an emitting optical fiber that carries Raman-scattered light from the specimen. The emitting optical fiber has a metal buffer layer. A spectral detector receives light from the receiving optical fiber in the probe. A filter module includes a filter that transmits the wavelength of the laser source but blocks wavelengths longer than the source between the source and the emitting optical fiber or the probe. The filter module is coupled to the probe by a linking optical fiber.