Abstract: An electronic apparatus comprising a material having photoconductivity, an energy bandgap, and trap levels. The material is typified by a thin film of polycrystalline diamond. The material is illuminated with a first electromagnetic emission, (which may include visible light, ultraviolet light, gamma rays, or x-rays) having photon energies smaller than the energy bandgap of the material. Then, the material is illuminated with a second electromagnetic emission having photon energies greater than the energy bandgap of the material to thereby induce a photocurrent. The amount of the first emission can be known by measuring the induced photocurrent.

Abstract: A method for calibrating a gas analyzer (1). A gas analyzer is calibrated by measuring the zero level of the analyzer (1). The level of the analyzer is measured, after a preceding reset, whenever a temperature variation (.DELTA.T) of an infrared sensor (14) included in the analyzer (1) or of a component thermally connected in a highly conductive manner thereto exceeds a predetermined threshold value (A), or the temperature variation rate (D) of the infrared sensor (14) of the analyzer (1) or of a component thermally connected in a highly conductive manner thereto exceeds a predetermined limit valve.

Abstract: A test arrangement for assessing the spectral energy distribution-determined response of a night vision device or other electro-optical apparatus. The test arrangement provides a library of spectral energy-distributed test signals or input scenes which may be selected to represent for example typical or extreme conditions expected during field use of the tested night vision device. The test signals originate in an array of energy transducer devices such as light emitting diode elements with each such light emitting diode element proving a limited wavelength component of the wide band composite optical signal received at the input port of the night vision device. Each component signal is arranged to be controlled electrically in presence or absence and also controlled electrically in radiance or intensity according to the needs of the scene being presented; such control is provided by a manual controller or by a programmed digital computer or by other controlling apparatus such as a programmed logic array.

Abstract: A method for the correction of uniformity of a gamma camera comprising a detector giving, for each pixel i,j having coordinates x.sub.i, y.sub.i, a number n.sub.ij representing the number of scintillations recorded in said pixel. The method comprises an initial step consisting in:placing a point source at a finite distance from said detector;acquiring the number n.sub.ij at each pixel i,j,computing the parameters x.sub.o, y.sub.o, z.sub.o that minimize the function: ##EQU1## N.sub.ij being defined by the expression ##EQU2## in which: x.sub.o, y.sub.o are the coordinates of the point source in the plane of the detector,z.sub.o is the distance from the point source to the plane of the detector,N.sub.o is the signal at the pixel having coordinates x.sub.o, y.sub.o,multiplying the number n.sub.ij of each pixel by a coefficient proportional to: ##EQU3## Application to medical imaging using gamma camera type display devices.

Abstract: A method for monitoring a property of a polymeric mass such as a coating or film comprising the steps of adding a fluorescence probe compound capable of fluorescing to a polymeric composition which has the ability to undergo changes in microviscosity, the ratio of the intensity of the fluorescence emission of said compound at two wavelengths changing in response to said changes in said microviscosity of said composition; curing said composition; causing said compound to fluoresce; measuring the fluorescence of said compound; calculating the ratio of the intensities of fluorescence emission of said compound at two or more wavelengths; relating said ratio to the monitored property of said composition.

Abstract: A non-destructive unambiguous method of measuring the presence and level of acid sulfates, particularly ammonium bisulfate in air is disclosed including infrared energy absorbance measurements of particles deposited on the filter through which the air passes.

Abstract: An arrangement for recording an IR image of an object. The arrangement has a focal plane array (FPA) of IR detectors and an optic which images the object on the focal plane IR detector array. At least one temperature reference is arranged in the beam path of the focal IR detector array. At least one IR reference detector is assigned as a reference among the IR detector elements in this array. Each temperature reference is coordinated with at least one of the IR reference detector elements so that each of the IR reference detector elements is impinged upon by radiation deriving essentially solely from one of the temperature references. An IR detector reference output signal is intended to be produced for each temperature reference. Each IR reference output signal is intended to set an individual reference level for the output signals from the remaining IR detector elements in the IR detector array.

Abstract: Row variable offsets in a large area solid state x-ray detector are compensated for. Initially, a calibration is performed to determine the row variable offsets. The calibration is achieved by measuring the average offset of each row. During normal operation, this offset is compensated for in a converting circuit. The required signal range of the converting circuit is consequently reduced.

Abstract: An imaging device (10) includes an array (18) of picture elements (16) or pixels, each of which is responsive to incident radiant energy to provide an output signal. The array (18) consists of pixels (16) in adjacent horizontal rows, each row having a certain pitch (P) or center-to-center distance between pixels. Each alternate row is horizontally offset by a distance equal to one-half of a row pitch from each adjacent row to form a "brick wall" or quincunx pattern. An azimuthal traverse of the quincunx focal plane array (18) provides twice the azimuthal resolution and approximately 140 percent of the minimum resolvable temperature measurement capability of conventional focal plane arrays.

Abstract: 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 light, which is emitted from the front surface of the stimulable phosphor sheet, and the light, which is emitted from the back surface of the stimulable phosphor sheet, are detected respectively with two photoelectric read-out devices, and two image signals are thereby obtained. The two image signals are added to each other in a predetermined addition ratio.

Abstract: A gamma camera for a Positron Emission Tomography (PET) system comprises a single, continvous scintillation crystal having an imaging surface, and a first layer of septa disposed along the imaging surface between the object and the imaging surface. A gap is provided between the imaging surface and the first layer of septa to allow non stray radiation to reach the imaging surface. The septa may be arranged to have a long axis disposed at an acute angle away from perpendicular to an axis of rotation or made to move in relation to the imaging surface of the scintillation crystal to reduce cold spots on the image. Multiple layers of septa may be provided.

Abstract: A focal plane array (FPA) mounted in an imbalanced configuration including several layers of materials with differing thermal expansion coefficients (TECs), moduli of elasticity, and thicknesses to maintain surface planarity and improve the reliability of the FPA during thermal cycling and excursions. An optical substrate is coupled to a multiplexer through an array of indium bumps. The typical TEC mismatch between the optical substrate and the multiplexer is eliminated by forcing the multiplexer to exhibit an effective TEC equal to that of the optical substrate by particularly selecting the types of materials used and the thicknesses of the individual layers of the composite structure. Consequently, undesirable deflections and distortion of the multiplexer and the indium bumps are minimized, thereby substantially improving FPA reliability.

Abstract: On line and essentially continuous measurements of hydrogen peroxide vapor in the presence of water vapor can be made using near infrared (NIR) spectroscopy using fiber optic cables to transmit infrared radiation between, e.g, a sterilization chamber and the NIR instrument. Hydrogen peroxide absorbs selectively at about 1420 nm, where water vapor also absorbs, but the absorbance at 1420 nm can be corrected for water vapor measurements at remote wavelengths where H.sub.2 O.sub.2 is transparent. The measurement process also may be incorporated into a control system assuring optimum hydrogen peroxide vapor concentrations for the sterilization procedure.

Abstract: An infrared sensor includes a linear array of plural photoconductive sensor elements, and a similarly linear multiplexing circuit arranged in side-by-side relation with the linear array of sensor elements. The multiplexing circuit includes a matching plurality of signal input ports, and a wirebond of plural conductors substantially in parallel conducts signals from the plural sensor elements of the array to the respective signal input ports of the multiplexer circuit. The multiplexer circuit includes a matching plurality of adaptation circuits or cells interposed between the respective sensor elements of the array and the input ports of the multiplexing circuit. Each adaptation cell includes a multi-position switch which by its position varies the transfer function of a feed back circuit of the adaptation cell. Plural modes of signal processing for each individual sensor element of the array are provided according to the positions of the multi-position switches of the plural adaptation cells.

Abstract: With a controlled scanning device (5, 6, 7), such as a FLIR, the scene which provides a modulated source is scanned with the scanning frequency being changed. This results in scanning of the scene with two different known scanning frequencies. By knowing the change in sampling frequency and correlating the changes in the Fourier frequency results in a spectrum analyzer (13), the frequency of the modulated source, including a source modulated at frequencies higher than the sampling rate of the sensor, is remotely measured.

Abstract: The change in the peak fluorescence wavelength of a small amount of a fluorescent compound, i.e., a fluorophore, which has been dissolved in a polymerizing material or a thermoplastic polymer is used to determine the extent of cure or solidification, respectively. The measured wavelength-shift can either be compared with a previously determined correlation to obtain an absolute value for the extent of cure, or can be utilized to compare or maintain an acceptable extent of cure throughout a manufacturing or a clinical process. Similarly, in the processing of a thermoplastic polymer by injection molding, the measured wavelength shift can either be compared with a previously determined correlation to obtain an absolute value for the temperature of the polymer, or can be utilized to adjust the injection molding cycle so that the mold is opened at the optimum times.

Abstract: A gamma ray camera for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer.

Abstract: Apparatus and method for qualitatively and quantitatively analyzing a complex radiation field are provided. A passive microdosimetry detector device records the energy deposition of incident radiation using an array of microstructure non-volatile memory devices. Each microstructure non-volatile memory device is capable of storing a predetermined initial charge without requiring a power source. A radiation particle incident to a microstructure non-volatile memory device is termed an "event". Each such event may generate a charge within a sensitive volume defined by the microstructure non-volatile memory device. The charge generated within the sensitive volume alters the stored initial charge by an amount falling within a range corresponding to the energy deposited by certain particle types. Data corresponding to such charge alterations for a plurality of microstructure non-volatile memory devices within an array of such devices are presented to a qualitative analyzing device.

Abstract: A method of determining porosity of an earth formation penetrated by a wellbore including irradiating the earth formation with bursts of neutrons from a source in the wellbore and counting epithermal neutrons at a first detector axially spaced from the source to be primarily responsive to output of the source. Counting neutrons is divided into buildup periods contemporaneous with the bursts and decay periods between bursts. Neutrons are counted at a second detector during buildup and decay, the second detector axially spaced from the source and radially displaced towards the wellbore to be responsive to epithermal neutrons from the formation and relatively insensitive to lithology. Neutrons are counted at a third detector during burst and decay, the third detector axially spaced from the source and radially displaced towards the wellbore to be primarily responsive to epithermal neutrons from the formation, but the response is partially affected by said lithology.

Abstract: The x-ray imaging system comprises an x-ray source for producing an x-ray beam and an x-ray detector. The x-ray detector comprises a solid state integrated circuit having a silicon substrate. The detector is constructed as a PiN diode with the voltage bias direction parallel to the direction of incident radiation. A tissue sample, such as a breast, is positioned between the x-ray source and x-ray detector. The x-ray detector directly receives the x-ray photons transmitted through the tissue and produces electrical signals. The detector signals are processed to provide a digital image of the tissue sample.