Abstract: A system for sensitively discriminating against background radiation which tends to swamp and prevent detection of radiation from a source of interest such as IR (Infra-Red) light radiation as may be found on “low observable” aircraft collision avoidance lighting, utilizes the modulation of such radiation as a mechanism for tracking the radiation and discriminating against the background radiation, for example, from other light energy sources.

Abstract: A radiation detector for detecting ionizing radiation. The detector includes a semiconductor having at least two sides. A bias electrode is formed on one side of the semiconductor. A signal electrode is formed on a side of the semiconductor and is used to detect the energy level of the ionizing radiation. A third electrode (the control electrode) is also formed on the semiconductor. The control electrode shares charges induced by the ionizing radiation with the signal electrode, shielding the signal electrode until the charge clouds are close to the signal electrode. The control electrode also alters the electric field within the semiconductor, such that the field guides the charge clouds toward the signal electrode when the clouds closely approach the signal electrode. As a result, signal loss due to trapped charge carriers (i.e., electrons or holes) is minimized, and low-energy tailing is virtually eliminated.

Abstract: A scintillation camera including photosensors for producing an output in response to emitted light; a scintillation material for emitting light directed to the photosensors in response to radiation absorbed by a source, the scintillation material formed in two or more segments defining an optical interface between adjacent segments; and an increased surface area at the interface for improving the transmissivity of the interface and efficiently optically coupling the adjacent sensors.

Abstract: Filmless photon imaging sensor plates and apparatus which are particularly effective in medical radiology and industrial applications including, but not limited to high resolution mammography. In combination, the sensor plates and apparatus provide rapid production of high resolution images which exhibit higher sensitivity and wider dynamic range than contemporary X-ray systems. Novel sensor plate structures provide images having attributes of increased sensitivity; dual plate design providing increased pixel read-out speed and differential dual energy image production; and electrically isolated segments by which a plurality of pixels are read concurrently to reduce overall image processing time. Generally, the plates employ a homogeneous photoconductive material such as amorphous selenium and are read by exposing each pixel sized area to a small diameter scanning light beam. Using light beam scanning, resulting plate design promises low cost manufacture of both sensor plates and associated apparatus.

Abstract: Labeled targets on a support synthesized with polymer sequences at known locations according to the methods disclosed in U.S. Pat. No. 5,143,854 and PCT WO 92/10092 or others, can be detected by exposing marked regions of sample to radiation from a source and detecting the emission therefrom, and repeating the steps of exposition and detection until the sample is completely examined.

Abstract: Systems and methods for infrared detection are described. An optomechanical photon detector includes a semiconductor material and is based on measurement of a photoinduced lattice strain. A multicolor infrared sensor includes a stack of frequency specific optomechanical detectors. The stack can include one, or more, of the optomechanical photon detectors that function based on the measurement of photoinduced lattice strain. The systems and methods provide advantages in that rapid, sensitive multicolor infrared imaging can be performed without the need for a cooling subsystem.

Abstract: A fluorescence detection apparatus is provided which has a partial reflection mirror 8 for transmitting a part of fluorescence light emitted from a fluorescent substance by projecting excitation light and reflecting the rest of the fluorescence light, and a pair of a first and a second photodiode 2,3 for measuring the light transmitted through or reflected by partial reflection mirror 8 respectively at a selected wavelength, and the pair of the first and the second diodes are arranged to be optically equivalent relative to the partial reflection mirror 8. This fluorescence detection apparatus is affected less by positional deviation of the measurement cell relative to the optical measurement system.

Abstract: A chopper is provided of solid state construction. Two layers are provided adjacent one another with the area between the layers defining one or more diffusion zones. One or more voltage potentials may be applied across the second layer to correspond to the diffusion zones. At an initial state the voltage potentials are either zero or some predetermined value which causes the index of refraction of the two layers to be substantially the same. At a second state the voltage potential equals some predetermined value to cause the index of refraction of the second layer to be different from that of the first layer. The difference in index of refraction between the layers creates a diffraction grating in the respective diffusion zone to diffuse that portion of an incident signal passing through the diffusion zone.

Abstract: A high temperature photocurrent detector circuit including a transimpedance amplifier having multiple stages of gain, and a driver amplifier which generates a driver current that is proportional to the photocurrent flowing through a photocurrent sensor. The voltage source utilizes source voltage wires to generate a supply current that is proportional to the driver current enabling the photocurrent detector circuit to operate as a two wire photocurrent detector circuit.

Abstract: A method and apparatus are provided to concentrate and detect very low levels of radioactive noble gases from the atmosphere. More specifically the invention provides a method and apparatus to concentrate xenon, krypton and radon in an organic fluid and to detect these gases by the radioactive emissions.

Abstract: Thermal imaging chopper (20) may comprise a disk (40) formed of a thermally transmitting material. The disk (40) may include a structure (44) operable to randomly scatter thermal radiation of the scene (14).

Abstract: A photo semiconductor element is covered by a cap with an incident window permitting incident light to penetrate through a translucent member. The photo semiconductor element detects a quantity of incident light penetrating through the translucent member of the incident window. The translucent member of the incident window is made of a material capable of suppressing the transmitting light quantity of incident light components having wavelengths less than 700 nm and larger than 900 nm. A photoelectric current output of the photo semiconductor element is controlled by the incident light penetrating through the translucent member of the incident window. The photo semiconductor element operates in multiple ways as a thermosensing sensor and a photosensing sensor.

Abstract: A counterfeit detection viewer apparatus for detecting security markings in paper currency. The counterfeit detection viewer apparatus includes a viewer housing having a detection opening on the bottom thereof for receiving the paper currency to be inspected and a viewing opening on the top thereof for inspecting the paper currency. The counterfeit detection viewer apparatus further includes a pair of holding brackets for detachably holding the counterfeit detector unit within the viewer housing which is usable within the housing and is removable for use as a hand-held counterfeit detector unit in a dark room or dark area. The counterfeit detector unit includes a UV light fixture mounted in the counterfeit detector unit having a UV fluorescent lamp for projecting UV light rays toward the detection opening and the paper currency to be inspected. The UV fluorescent lamp being less than 0.5 cm from the detection opening.

Abstract: Apparatus for the optical detection of selected toxic gases, using the ultraviolet region of the electromagnetic spectrum, and the known absorption properties of the toxic gases in the ultraviolet region. An ultraviolet flashlamp source illuminates a straight, highly polished metal tube with numerous perforations to permit access for the gas to be detected. The ultraviolet light then enters an optical compartment comprising an optical beamsplitter and two ultraviolet detectors with wavelength selective narrowband filters attached. The filters are selected so that one overlaps the region of absorption by the gas while the second is in a region where there is no absorption by the gas. The electronic circuit following the ultraviolet detectors and the drivers for the flashlamp, are timed by a microprocessor that provides the means for the electronics and data processing to be synchronized with the flashlamp pulse.

Abstract: The invention is a method and system for detecting, by means of specific processings of images of an area flown over taken in several spectral bands, signs indicative of a stress of the vegetation and the presence of spots where fire is likely to occur or spread. Images of the area flown over are acquired by means of a photography device (1) in a first spectral band selected in the red part (R) of the visible spectrum, in a second spectral band of the near infrared spectrum (N.I.R.) and in a third spectral band in the thermal infrared spectrum selected to locate parts of the area showing both a hydric stress and hot spots. Coded composite images are obtained by color coding of the aforementioned spectral bands and the images obtained in the three spectral bands are combined by means of a processing system (12, 13), which identifies fire development hazards caused by water deficit and local overheating. The system can be used for fire forecast, protection and fighting.

Abstract: A plate for positioning a radiation test wipe in alignment with a sensor on a radiation monitoring instrument includes a recessed mounting area on the plate that conforms to the geometry of the wipe. Guide members on the plate slidably engage brackets attached to a back panel of the instrument. The plate is therefore removable and can slide into a position along the instrument where it contacts a slide stop integral to the brackets. This causes the test wipe to be aligned directly under the sensor to provide consistent readings.

Abstract: A nuclear imaging radiation system including a gamma camera which, in one embodiment, includes a scintillation crystal, a collimator and an array of photomultiplier tubes, is described. The collimator is positioned adjacent a face of the crystal, and defines a field of view. The array of photomultiplier tubes is positioned adjacent an opposite face of the crystal, and selected tubes outside the field of view are disabled so that light events outside of the field of view are not processed.

Abstract: An IR focal plane array (IR-FPA) includes an IR radiation detector (11a) having a plurality of IR radiation responsive photodetectors (PDs) and a readout integrated circuit (11) that includes a plurality of unit cells arranged in an N.times.M matrix. Each unit cell has an input coupled to an output of one of the IR radiation responsive photodetectors. The IR-FPA further includes M column amplifiers, preferably CTIAs, individual ones of which have an input that is coupled through one of N switches (.phi.tr) to individual ones of the N unit cells. A charge integrating capacitance in each unit cell is formed by a charge well underlying one (.phi..sub.1) of a plurality of transfer gates coupled between individual ones of the N unit cells that are coupled to one of the M column amplifiers.

Abstract: A measuring device for determining the concentration of gases with two identical radiation sources and two radiation detectors, which delivers stable measured values despite the contamination that occurs or the shielding from radiation of the outer optical surfaces exposed to the gases or to mixtures of gases and despite possible mechanical disadjustments. The two radiation detectors are provided with an optical concentrator each for bundling the radiation, and being arranged in a gas-tight housing together with the two identical radiation sources and with a beam splitter. One radiation source is directed through a window that is transparent to infrared light to a plane mirror outside the gas-tight housing, and the beam path reflected by the plane mirror falls through the window that is transparent to infrared light onto the beam splitter.

Abstract: An ultraviolet transmittance analyzer for fabrics, translucent packaging, sunscreen products and the like using an internally pulsed white-light illuminated integrating sphere, exiting sample and reference diffusely reflected beams, and applying them respectively to separate sample and reference spectrographs with light detector arrays.