Abstract: An optical waveguide sensor particularly useful as a chemical or biological sensor is described which comprises a single mode fibre optic waveguide including a core surrounded by a cladding and having a tapered portion which tapers adiabatically inwardly to a waist of diameter typically about that of the original core, and then adiabatically outwardly by variation of the cladding whereby under operating conditions the evanescent electromagnetic field associated with the guided mode of the waveguide is externally accessible in the region of the tapered portion; an optical source, such as a laser, optically coupled to one end of the waveguide; and a detector coupled to the other end of the waveguide for detecting optical radiation modulated or coupled into the waveguide at the tapered portion.

Abstract: The present invention comprises an in vitro system called the Diffusion Matrix Vessel and a method of using fluorokinetic analysis for quantifying the diffusion of a fluorescent material through the vessel and thereby characterizing the permeability of the vessel. The results obtained from the gel can be used to verify and develop protocols for investigating and treating angiopathies of the eye related to blood vessel permeability.

Abstract: As photodetectors for detecting light radiated out of a recording sheet, on which a radiation image has been recorded, during its scanning with reading light, at least a single first photodetector, which has a high detection sensitivity and is apt to undergo a saturation phenomenon at its photoelectric surface, and at least a single second photodetector, which has a low detection sensitivity and undergoes little saturation phenomenon at its photoelectric surface, are utilized. A maximum amount of the amounts of the light, which is radiated out of a region inside of each of predetermined units in the radiation image recorded on the recording sheet, is measured. Image signal components corresponding to a unit, in which the measured maximum amount of the radiated light is larger than a predetermined value, are obtained by using only the signal having been generated by the second photodetector.

Abstract: In a method for detecting an energy level of residual noise on a stimulable phosphor sheet, a stimulable phosphor sheet, on which a radiation image has been stored, is exposed to stimulating rays, which cause it to emit light in proportion to the amount of energy stored thereon during its exposure to radiation. The emitted light is detected, and the radiation image is thereby read out. A predetermined amount of erasing energy is given to the stimulable phosphor sheet, from which the radiation image has been read out, and noise having an energy level not higher than a predetermined energy level, which noise is among noise due to radiation image information remaining on the stimulable phosphor sheet, is thereby erased. Residual noise is then read out from the stimulable phosphor sheet, on which the noise having the energy level not higher than the predetermined energy level has been erased. An energy level of the residual noise, which has thus been read out, is then detected.

Abstract: A method and apparatus for adjusting the raw, instantaneous response of an NDIR and determining a linear response therefrom is disclosed. The NDIR detector cell is connected to an output which is adjusted according to the function (Ax)/(1-x) where the coefficient A is a constant for the NDIR being used, and x is the raw, instantaneous, response of the detector. The coefficient A is determined by assessing the maximum response of the NDIR with an infinite mass of analyte within the sample cell.

Abstract: A digital signal processing system (100) removes DC bias in the output of a pyroelectric detector and similar types of detectors by adding together a first output signal which is inverted and a second output signal which is not inverted. The system (100) also removes offsets in the detector signal introduced by electronic circuits (readouts, amplifiers, drivers, etc.) between the detector and the system (100).

Abstract: A band analysis system for determining the optimal signal-to-noise ratio between the spectral emissions from an object of interest and the spectral emissions from background noise for a target detecting and tracking system. Known target and background spectra are applied to a band select system in order to select an initial choice of bands. These bands are then applied to a sensor model system which determines a template for each spectrum. The templates are applied to a noise generation system in order to generate a noise function indicative of the vibrational noise of the sensor and the electronic noise of the system. The noise function also includes a function of the integration time over each band. The noise function and the templates are then used to determine a signal-to-noise ratio based on a weighting function. The signal-to-noise ratio is applied to the band select system and the integration time select system in order to adjust the bands and their integrations time to the optimum value.

Abstract: An apparatus for detection and measurement of trace species in a sample gas. A ring down cavity cell is filled with the sample gas. A continuous wave laser emits radiation, which is directed from the continuous wave laser to the ring down cavity cell where it resonates. A photodetector measures radiation levels resonated by the ring down cavity cell and produces a corresponding signal. The decay rate of the ring down cavity cell is calculated from the signal produced by the photodetector and is used to determine the level of trace species in the sample gas.

Abstract: This invention provides an imaging system for producing images from electromagnetic radiation such as x-rays. The system includes a detector comprised of a radiation-absorbing layer sandwiched between an array of CMOS integrated circuits (which we call pixel circuits) and a surface electrode layer transparent to the radiation. Each of the pixel circuits in the array has a charge collecting electrode. An external voltage applied between the surface electrode layer and the charge collecting electrodes produces an electric field across the thickness of the absorbing layer. Radiation passing through the transparent surface electrode layer is absorbed in the absorbing layer creating electron/hole pairs in the absorbing layer. A portion of the liberated holes (or electrons) migrates under the influence of the electric field toward the charge collecting electrodes, which collect the holes and store them as charges on small capacitors located within each circuit.

Abstract: A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone.

Abstract: Inks have been discovered that are selectively excitable by different wavelengths of incident radiation. This allows a lower layer bar code to be written on an object with an invisible ink and an upper layer bar code to be written over the lower layer bar code with an ink that is invisible to the naked eye. The apparatus of this invention is a detector that is able to read the upper and lower layer bar codes.

Abstract: A combination is provided comprising a supported or self supporting photostimulable phosphor panel, comprising a photostimulable phosphor layer, the phosphor being capable of storing energy upon irradiation with X-rays and of releasing the stored energy as stimulated emission light upon irradiation with stimulating light and collecting means for stimulated emission light, and showing a restricted angular aperture. The combination comprises a volume reflection hologram H1, situated between the phosphor panel and the light collecting means. The volume reflection hologram H1 reflects stimulated emission light entering the volume reflection hologram under any angle outside a restricted angle, determined by the angular aperture of the collecting means and transmits stimulated emission light entering the volume reflection hologram under the predetermined restricted angle.

Abstract: An apparatus for detecting leakages in structural members (8) is disclosed. The apparatus includes a device (2) for conveying gas through the structural member (8) to be investigated, a camera (14) having a narrow band filter characteristic matched to the spectral absorption of the gas and a device (16, 18) connected to the camera (14) for processing and displaying the recorded image of the structural member (8) to be investigated.

Abstract: A method for the two-photon excitation of long-lived fluorescent or phosphorescent dyes with long low-power pulses. In the method time-resolved detection is used to detect long-lived dyes. In the method long-lived dyes are excited to the excited state with light pulses of long duration via double-photon absorption. In the two-photon absorption process the chromophor of the dye molecule is excited through the summation of the energies of two or more photons when they are simultaneously absorbed. As the method is based on the use of pulses of long duration and on time-resolved detection the peak power of the pulses may be kept low. Long pulses of low power can be produced with a great variety of low-power light sources. The light source may in this case be e.g. a semiconductor laser. The excitation technique according to the invention may exploit the doubling or multiplication of the excitation wavelength or the nonlinearity of the two-photon absorption process.

Abstract: First and second scintillation camera detectors are provided and are mounted, respectively, to first and second yoke assemblies. The first yoke assembly is mounted to a ring gear which is rotatable within a vertical plane about a horizontal axis. The second yoke assembly is mounted to an annulus which is located within the ring gear and which is rotatable within the plane and about the axis. A rotating device is provided for rotating the ring gear in the plane and about the axis and a locking device is also provided for locking the first and second yoke assemblies together, whereby the first and second yoke assemblies rotate together when they are locked together and the first yoke assembly is being rotated by the rotating device. Advantageously, each detector is pivotally secured to its corresponding yoke assembly and each of the detectors is radially movable towards and away from the axis of the gantry. Further advantageously, the entire gantry is laterally moveable.

Abstract: A gamma ray imaging camera system and method for using it are described which in representative embodiments include a gamma ray collimator, a scintillator adjacent the collimator for converting gamma photons into visible photons, a low level visible photon detector including at least two optically coupled inverter tubes, a high-speed lens for imaging the visible photons onto the detector, a video imager for receiving, recording and storing sequential images of the visible photons defining the detector output, and a programmed computer for processing the images and determining the spatial distribution of the images.

Abstract: A flow cell for use in optical measuring systems particularly suited for use with liquid food products is provided. The flow cell is manufactured from a single unitary piece of synthetic resin which is transparent to light in the near infrared range. Because the flow cell is constructed from a single piece, the interior surface is continuous and the presence of undesirable cracks or crevices is avoided.

Abstract: A method for determining the porosity of an underground formation includes the steps of irradiating the formation with neutrons, detecting and measuring gamma rays resulting from irradiation of the formation, discriminating between gamma rays from the formation and gamma rays from the tool, and using a measurement of the gamma rays from the tool to determine the formation porosity. A suitable logging tool includes a neutron source, a gamma ray detector, means for discriminating between gamma rays from the formation and gamma rays from the tool, and means for relating the gamma rays from the tool to the formation porosity.

Abstract: The device of the invention employs a small Teflon.RTM. vial which is mounted in a vertical position in a plastic box, and a segment of screen attached to a rod which can be raised or lowered into the reaction vessel which contains liquid reactants. When raised, the screen carries a sample into a portion of the vessel having IR transparent parts, axially aligned with corresponding parts in the plastic outer container. The device is positioned in an FTIR spectrometer. Data obtained from successive IR scans are used to follow the progress of a chemical reaction.

Abstract: A radiation image storage panel comprises a stimulable phosphor layer, a cushioning layer and a coated protective layer, wherein the cushioning layer shows an elongation at rupture more than that of the protective layer.