Abstract: In a method for manufacturing a calibrated radiation dosimeter, a layer of radiation sensitive material is applied to a substrate, the radiation sensitive material having an optical density which varies in accordance with a degree of radiation exposure. A pre-exposure optical density of the layer of radiation sensitive material is optically measured and subsequently the layer of radiation sensitive material is exposed to a known dose of radiation. Thereafter, a post-exposure optical density of the layer of radiation sensitive material is optically measured. Using at least the pre-exposure optical density, the post-exposure optical density, and the known dose of radiation, one computes mathematical parameters defining a predetermined mathematical function. The computed mathematical parameters are applied in encoded form to the substrate (e.g., printed in bar code form on the substrate or a holder card).

Abstract: A sensing apparatus for spectral analysis in which the sensing head is bi-layered. The layer contacting the sample is formed of corrosion-resistant material, e.g., diamond. It is engaged by a supporting layer formed of infrared transparent material, e.g., zinc selenide through which radiation passes on its way to and from the sample-contacting layer. In order to avoid non-linearity in the sample absorbance results, incoming paraxial rays are all reflected in such a way that they are reflected at the same angle, and the same number of times, from the sample contacting surface of the corrosion resistant layer. The incoming rays may be reflected at a conical surface, or at a flat rooftop-like surface. The exiting rays are preferably reflected so that they are parallel to the incoming rays. Where a conical reflecting surface is used, it may be a surface of the zinc selenide layer, or a highly reflective surface provided by another element.

Abstract: A method for determining a level of exposure to radiation utilizes a radiation dosimeter comprising a substrate provided with a radiation sensitive layer or patch having an optical density which varies in accordance with the degree of radiation exposure. In addition, the substrate is provided with optically readable coding which identifies one or more encoded mathematical parameters for enabling an automated calculation of dosage from a detected optical density change of the radiation sensitive material. In the method, the coding on the dosimeter substrate is scanned to automatically determine the encoded mathematical parameters, and a plurality of pre-exposure optical densities and a plurality of post-exposure optical densities of the layer of radiation sensitive material in a plurality of wavelength bands are optically measured.

Abstract: A two-dimensional imaging backscatter probe has a radiation source, a radiation detector, and a position sensing device to which the radiation detector is attached. A mapping circuit generates a two-dimensional map of backscattered radiation as a function of position of the radiation detector. A display displays the two-dimensional map. The two-dimensional imaging backscatter probe of the present invention facilitates non-destructive/non-intrusive inspection of a test article for contraband and/or structural integrity inspection.

Abstract: A dual-head gamma camera imaging system comprises a master ring gear and a slave ring rotatable about a longitudinal axis. The master ring gear is rotatably supported by a gantry. The slave ring is rotatably supported by the master ring gear and concentric with the master ring gear, such that the master ring gear and the slave ring can be rotated independently about s longitudinal axis. A first detector is supported by a first cantilever support member mounted to the master ring gear. A second detector head is supported by a second cantilever support member mounted to the slave ring. The angular displacement between the detector heads can be varied by providing relative rotation between the master ring gear and the slave ring. The rotation can be accomplished by using the weight of one of the detector heads to hold that detector head stationary while rotating the other detector head using a motor.

Abstract: A system for tagging products or substances for retrospective identification using controlled abundance ratios of multiple isotopes in each of one or more elements in the tagged substance. The abundance ratios of the isotopes of the tagging elements are measured by suitable means to determine the identification code of the tagged product of substance.

Abstract: An image processing apparatus includes a histogram producing section for producing a histogram of density signal levels of pixels constituting the image data, a reference density signal level detecting section for detecting from the histogram a density signal level processed by the maximum number of the pixels in a range excluding the maximum value and the minimum value of the density signal levels, a density signal level conversion range determining section for successively comparing the number of the pixels of each density signal level with a threshold value from the density signal level processed by the maximum number of the pixels to lower density signal levels, thereby determining a density signal level lower limit value of density signal levels to be converted and successively comparing the number of the pixels of each density signal level with a threshold value from the maximum value of the density signal level to lower density signal levels, thereby determining a density signal level upper limit value

Abstract: The crystals are sealed by either glass-to-metal seals or epoxy to prevent moisture degradation. Combined with the multiple moisture barriers, the new configurations are long lasting and provide long life for the modular detectors. The crystal geometry depends on the application. The crystal surfaces are shaped in such a way that provide minimum optical paths of the light photons. The cladding layers and the mirror system provide gas-free, high reflectivity crystal mirror surfaces. The mirrors can be specular or diffusive. Curved shapes at the photo detector sides provide the first step in focusing the light. Focused photon beams are easily translated into smaller photodetectors that have higher signal-to-noise ratio, are more compact in nature, are more economical. Crystals have upper and lower truncated conical or pyramidal portions and intermediate straight wall portions. The crystals have rounded bottoms and tops, and cladding on the crystals and mirrors on the cladding or on interior walls of a housing.

Abstract: A gamma camera is equipped with a graded filter plate in lieu of a collimator so that the gamma camera can perform PET studies. The filter plate prevents detection of Compton scattered, positron annihilation photons produced in the patient while permitting detection of photons which have experienced Compton scattering within the camera's scintillation crystal to significantly increase the camera's usable count rate. Additionally, the filter is fitted with a protruding baffle shielding the camera from stray 511 Kev radiation.

Abstract: A method for observing wiring patterns of a printed circuit board includes the steps of projecting light having a wave length within an infrared range on the printed circuit board, detecting reflected light from the printed circuit board, and forming an image based on the reflected light, so that the wiring patterns of the printed circuit board is observed through the image.

Abstract: A novel scatter filter for use in positron emission tomography which filters out deflected rays of energy due to Compton scattering which generally have a lower energy. The filter allows most of the undeflected rays to pass through by providing a layer of material having a particular density and atomic number between the detector and the source. Multiple layers of filters may also be provided to filter out characteristic x-rays from the first layer of filter.

Abstract: Apparatus (102, 202, 302) and method for tunneling rate infrared detection devices formed on a single substrate (100). A counter electrode (104, 207) having a plurality of portions extending from the substrate (100) with the counter electrode (104, 207) suspended above the substrate (100) at a distance from a tunneling electrode (116) so that a tunneling current flows through the counter electrode (104, 207) and tunneling electrode (116) in response to an applied bias voltage. The counter electrode (104, 207) and tunneling electrodes (116) form a circuit that produces an output signal. A force applied to the sensor (102, 202, 302) urges the counter electrode (104, 207, 304) to deflect relative to the tunneling electrode (116) to modulate the output signal. The output signal is a control voltage that is applied between the counter electrode (104, 207, 304) and a control electrode (114) to maintain a constant tunneling current.

Abstract: An apparatus for measuring isotopic ratios provides four separate optical paths for separate measurement of each of two isotopes relative to a reference signal, using spectrally resolved infrared radiation. The design permits the measurements to be made accurately without significant time lags between measurements, and without interchanging of cells or filters.

Abstract: Contaminants in corrosive gases are detected optically at concentrations below 1 part-per-million (ppm) and extending to a level below 1 part-per-billion (ppb) by using intracavity laser spectroscopy (ILS) techniques. A laser, the ILS laser, is employed as a detector. The ILS laser comprises a gain medium contained in a laser cavity. A gas sample containing gaseous contaminant species is contained within a gas sample cell which is placed inside the laser cavity and on one side of the gain medium. Accordingly, the corrosive gas is prevented from reacting with the components of the ILS laser. The output signal from the ILS laser is detected and analyzed to identify the gaseous species (via its spectral signature). The concentration of the gaseous species can be determined from the spectral signature as well.

Abstract: A fast atom beam source which can efficiently provide a fast atom beam having a diameter less than 1 .mu.m. The fast atom beam source has an ion source for ionizing a liquid metal to generate metal ions, a control electrode system for controlling the flux of metal ions, and a neutralizing chamber in which the ion beam is neutralized to generate a fast atom beam. The neutralizing chamber is disposed in a path of the ion flux. A neutralizing gas supply supplies a neutralizing gas into the neutralizing chamber, the neutralizing gas containing a metal element.

Abstract: In a clinical linear accelerator system for delivering charged particles for medical applications, a series of monolithic cavity-defining members is connected to form a succession of accelerating cavities, with temperature regulation being achieved by aligning internal cooling passageways through the series of monolithic members. As a result, a continuous coolant flow path is formed through the monolithic members. At each member-to-member interface, there is a leakage-release path for non-intrusively conducting any leakage that occurs at the interface. In the preferred embodiment, there is a braze connection that separates the leakage-release path at an interface from the coolant flow path at that interface. The braze connection provides a seal that further safeguards against coolant entering an area in which performance of the system is affected.

Abstract: The hybrid type infrared detector includes a plurality of photodiodes constructed by p-n junctions made of compound semiconductor material on a silicon substrate, a signal processing portion formed on another substrate, and a connecting member for electrically connecting the plurality of photodiodes with the signal processing portion, and for injecting carriers generated by the photodiodes into the signal processing portion, and is characterized in that partitioning portions are formed along the cleavage plane of the compound semiconductor material.

Abstract: A small radii mass spectrometer that utilizes high energy density permanent magnets of greater than 10E7 GOe for focusing an ion trajectory. The ion optical path employs focusing of the parallel component of the beam emitted by the source such that the momentum selected beam is focused in 90.degree. geometry at or near the exit pole face. The width of the beam at the focal point is independent of the size of the beam exiting the ion source in first order but has a second order aberration term dependent on the source width and radius of curvature. The dominant terms in determining the collected beam width are the angular divergence of the source (which can be reduced by defining slit) and the energy spread of the ion beam. A second magnet may be used in tandem with the first magnet to cancel the second order aberration term and reduces the background created by ions scattering with residual gas molecules in the vacuum chamber.

Abstract: An emission-concentration monitoring system (20)includes first and second monitor stations (22,32) which are separated by a sensing space (40) along a path (28) of a moving vehicle (26). Each station has a source of electromagnetic radiation (64) which is directed through the vehicle's exhaust plume. Each station also has a set of detectors (66) which are positioned to receive the radiation and configured to measure transmittances at wavelengths which are absorbed by molecular species of exhaust plume (e.g., hydrocarbons, nitric oxide, carbon monoxide and carbon dioxide). These sensed transmittances are converted to emission concentrations by a data processor (50) and compared to a set of emission-concentration standards. The vehicle is determined to be in violation only if its emission concentrations at both the first and second monitor stations exceeds the standards.

Abstract: A method for nondestructive/noncontact detection of alpha case on a surface of a workpiece made of titanium or a titanium-based alloy. Infrared radiation is reflected off of a selected portion of the workpiece surface and sensed by a detector which may comprise a scanning infrared radiometer, an infrared camera, or a spot radiometer. The presence of any alpha case in the selected portion of the workpiece surface is detected by comparing the intensity of the reflected infrared radiation to a predetermined intensity known to be indicative of the absence of alpha case. An image of the reflected infrared radiation may be created and the step of detecting the presence of alpha case may include the step of comparing the intensity of the reflected infrared radiation within the image to the predetermined intensity. According to a preferred embodiment, a target may be disposed between the source of the infrared radiation and the workpiece surface so as to create a predetermined pattern within the image.