Abstract: An infrared light beam, emitted from an infrared light source 4, arrives periodically and alternatively at a sample cell 1a and reference cell 1b through a rotating chopper 2. The beam, which travels through the sample cell 1a and reference cell 1b, is detected as a sample signal and reference signal by a detector 5. The chopper 2 has apertures 2a and 2a. Since the aperture 2a, which faces the sample cell 1a, and the aperture 2b, which faces the reference cell 1b, are each formed in an arc shape having a central angle of about 90 degrees, the amount of time for which the infrared light beam is emitted and not emitted to the sample cell 1b and the reference cell 1a are all about equal. Therefore, the non-dispersive infrared analyzer can obtain about twice the amount of information about the concentration of the gas to be measured than a conventional apparatus per one chopper rotation.

Abstract: Radioactive contamination on tubing is detected as the tubing is withdrawn from a wellbore. The tubing is moved past a detector located on the wellhead, preferably through an annular shaped detector, and means responsive to the detected level of radiation exceeding predetermined limits activate both an alarm to gain the operator's attention and means to apply indicia to the contaminated tubing.

Abstract: An oil concentration meter includes a sample cell for receiving an oil sample that can be irradiated with infrared rays from a light source. A first interference filter having a design wavelength of 3.4 .mu.m is positioned before a measuring detector, while a second interference filter transmitting a band range between 1 .mu.m and 5 .mu.m is positioned in front of a reference detector. A logarithm of the ratio of the reference detector output to the measuring detector output is used for determining the oil concentration in a sample.

Abstract: An apparatus for fluorescence of a biological sample includes a light illumination source, an ambient light-excluding optical chamber, a sample holder, a two-dimensional array charge coupled device ("CCD") sensor providing for on-chip signal integration of each pixel of the array, and an analog/digital converter for digitizing the CCD signal. Signal acquisition time from the array is varied so that the integrated signal from each pixel is below its saturation level. A darkfield value for each pixel is acquired and subtracted from the illuminated signal from that pixel so as to yield a darkfield corrected signal. The fluorescence value for each pixel can be compensated for variations in excitation energy reaching different sample areas. Image readout is through a single channel output.

Abstract: An ionization chamber for monitoring a radiation beam includes a housing having a primary beam passageway and a number of secondary beam cells that are adjacent to the primary beam passageway. The primary beam passageway passes entirely through the housing. In the preferred embodiment, a large-area beam measuring electrode and an array of small-area beam measuring electrodes are each coaxial with the primary beam passageway. Also, in the preferred embodiment, each secondary beam cell includes a beam measuring electrode. Because the portions of the radiation beam that enter the secondary beam cells do not pass through the ionization chamber, these portions do not contaminate the treatment beam, allowing the beam measuring electrodes within the cells to be dimensioned and configured so as to maximize signal strength.

Abstract: A method of coregistering medical image data of different modalities is provided. In the method, an emission scan of an object is performed using a nuclear medicine imaging system to acquire single-photon emission computed tomography (SPECT) image data. A transmission scan of the object is performed simultaneously with the emission scan using the same nuclear medicine imaging system in order to acquire nuclear medicine transmission image data. The emission scan is performed using a roving zoom window, while the transmission scan is performed using the full field of view of the detectors. By knowing the position of the zoom windows for each detection angle, the nuclear medicine transmission image data can be coregistered with the SPECT emission image data as a result of the simultaneous scans.

Abstract: A large area solid state x-ray detector employs a plurality of cells arranged in rows and columns composed of photodiodes that are charged, exposed to x-rays which deplete their charge in proportion to the exposure, and then recharged to determine the amount of exposure. Fast scanning of the photodiodes consistent with the reduction of dark current effects is obtained without ghost images by employing a non-imaging scan following the imaging scan. The non-imaging scan employs a greater proportion of each scan duration for charge restoration than the imaging scan. In one embodiment simultaneous non-imaging recharging of the photodiodes is performed to substantially reduce this non-imaging time.

Abstract: A radiation image stored on a stimulable phosphor sheet is read-out by exposing the stimulable phosphor sheet to stimulating rays, photoelectrically detecting light emitted by the stimulable phosphor sheet by a photomultiplier and converting it into an electric image signal in a read-out section while feeding the stimulable phosphor sheet through a read-out section toward an erasing section. Residual radiation image information on the stimulable phosphor sheet is erased by exposing the portion of the stimulable phosphor sheet which is fed to the erasing section after passing through the read-out section to first erasing light, and exposing the stimulable phosphor sheet to second erasing light while feeding the stimulable phosphor sheet through the erasing section toward the read-out section.

Abstract: The system and method of the present invention determines glue-line characteristics, such as temperature, of corrugated board. Components of an on-line glue sensor's output signal that are oscillating at the fluting frequency are isolated. The components of the sensor output signal that are sensitive to glue, which is only present on the tips of the flutes, oscillate at the fluting frequency. Those variations in the sensor output signal that are not oscillating at the fluting frequency are canceled out, while those that are oscillating at the fluting frequency are isolated and amplified, facilitating an accurate estimate of their amplitude. The output signal of an infrared absorption sensor will provide an improved on-line starch measurement for corrugators. The incremental amount of infrared radiation that is absorbed by starch and/or water in the glue-lines is isolated from the predominant, more random background absorption due to cellulose and water in the paper substrate.

Abstract: An integrated photovoltaic detector includes a reference photovoltaic detector and an active photovoltaic detector in a series connection. The reference detector produces a dark current that opposes the active detector's dark current. The active detector effectively masks the reference detector from incident illumination so that the active detector produces photocurrent but the reference detector does not. The band gap of the reference detector is preferably matched to the active detector so that their dark currents are substantially matched over a temperature range. As a result, the current read out of the integrated detector at the series connection is approximately equal to the photocurrent generated by the active detector. This improves the detector's SNR, signal resolution, and useful operating temperature range.

Abstract: A dose distribution analyzer (20) and methods for providing a radiation dose map indicating energy of a spacially variable radiation pattern beamed onto a dose map radiation dosimeter (10). The radiation dosimeter (10) is exposed to a proposed spacially variable radiation pattern such as used in a phantom patient for patient radiation dose treatment verification. The dosimeter (10) is subsequently analyzed by the dose distribution analyzer (20). Such analyzer includes a phosphor stimulator (53), an image forming subsystem (38), and an image sensor (37). A dosimeter holder (32) holds the dosimeter near the phosphor stimulator (53). A system controller (22) is connected to receive image data from the image sensor (37) while the dosimeter (10) is stimulated. The controller (22) utilizes the image data to derive a radiation dose map which indicates the distribution of radiation in the spacially variable radiation pattern which strikes the dosimeter (10).

Abstract: A directional thermal neutron detector for detecting thermal neutrons and determining the direction of the thermal neutron source. The directional detector includes an array of individual thermal neutron detector modules, each of which comprises front and back planar silicon detectors having a gadolinium foil sandwiched therebetween. The array comprises a plurality of individual detector modules which are angularly displaced with respect to each other. The direction of the thermal neutron source is determined by comparing the magnitudes of the output signals from the plurality of angularly displaced detector modules. Each thermal neutron detector module is segmented into four quadrants to reduce its capacitance and resultant noise. The thickness of the gadolinium foil in each thermal neutron detector module is at least 15 microns thick, to improve the front-to-back silicon detector counting ratio to ascertain the side (front or back) from which thermal neutrons are arriving at the detector.

Abstract: A detector comprises an infrared reflection layer and a diaphragm member, the infrared reflection layer and the diaphragm member facing each other, with a space intervening therebetween, and the diaphragm member comprises an infrared absorbable layer. A signal varies a distance between the diaphragm member and the infrared reflection layer, and thus a band of an absorbed wavelength is varied. The distance is varied by a voltage applied between a first conductive layer disposed at the infrared reflection layer side and a second conductive layer disposed at the diaphragm side. In driving the detector, a surface of the diaphragm is contacted with a surface of the structure temporarily by altering a voltage applied therebetween.

Abstract: A radiation imaging system includes a detector unit and a receiver unit. The detector unit includes a two-dimensional sensor, first and second amplifier channels, first and second multiplicity generators and first and second address generators. The two-dimensional sensor includes first and second sensing elements wherein the first sensing elements sense radiation in a first direction and the second sensing elements sense radiation in a second direction. The first amplifier channels corresponding to each of the first sensing elements. Each first amplifier channel generates an output signal based on a detection output from a corresponding one of the first sensing elements. The first multiplicity generator generates a first multiplicity signal representing a number of the first amplifier channels generating output signals. The first address generator generates a first analog address of a first amplifier channel associated with a received output signal.

Abstract: A method and apparatus for evaluating the composition of an oil sample. The method and apparatus are premised on the discovery that spectral differences can be observed in the luminescence, excitation, light scattering and absorption spectra in the near UV, visible and near IR regions for various crude oil components, such as asphaltenes, deasphalted crude oil and organic solid residues. Accordingly, in one preferred embodiment the method comprises illuminating an oil sample with light of a suitable excitation wavelength, measuring the resultant fluorescence therefrom and comparing the resultant fluorescence to appropriate standards derived from known components of crude oil.

Abstract: A method of measuring mass flow rates of liquid phases in a multiphase slug flow containing at least two liquid phases includes (i) passing a flow through a tube; (ii) detecting commencement of passage of a slug in the flow past a first location in the tube; (iii) measuring mass or volume fractions of the liquid phases by transmission of energy through the flow at the first location; (iv) detecting ending of the passage of the slug at the first location; and (v) determining mass flow rate of the liquid phases through the tube from (a) measuring the total mass or volume of liquid flowing through the tube and (b) measuring mass or flow fractions, only between detection of the commencement and the ending of passage of respective slugs in the flow, i.e., only while a slug is present at the measuring point.

Abstract: Circuitry for a bolometer-type image pickup device improves the signal-to-noise ratio and reduces variations of an output offset level due to temperature variations of the device. A clamp voltage is applied to an amplifier 18 via a clamping diode 36 connected thereto. This reduces a difference between an input voltage during an off-state of one of horizontal FET switches 9, 10, and an input voltage during the off-state of both horizontal FET switches 9, 10, thereby improving a signal-to-noise ratio by narrowing a frequency band of an external circuit.

Abstract: A passive source infrared gas detector which uses an ambient temperature source and the space between the detector assembly and the source as the sample chamber is provided, the gas detector includes an infrared detector assembly for producing a first output, a second output, and a third output, the first output being indicative of the radiation received by the detector assembly at a first non-neutral spectral band which is absorbable by a preselected gas to be detected, the second output being indicative of the radiation received by the detector assembly at a first neutral spectral band from the passive infrared source, and the third output being indicative of the radiation received by the detector assembly at a second neutral spectral band from the passive infrared source. Signal processing means are included for manipulating the three outputs to determine the concentration of the gas being monitored.

Abstract: To acquire both a scatter image and an emission image in nuclear medicine, it is chosen to detect the emission image by validating the radioactive events that occur in the nominal range of the radioactive marker chosen. For the scatter image, lower energy ranges are chosen, these ranges corresponding to the production of at least secondary or tertiary Compton photons. It is shown that it is possible, in this way, to reconstruct an artifact-free transmission image. This scatter image is used to correct the initially acquired emission image. It is shown that it is possible to acquire both images at the same time.

Abstract: An apparatus for collecting photons emitted by hot spots in an integrated circuit. Means are provided for intermittently energizing the circuit. A photon receptor detects the photons emitted by the circuit, and produces a photon signal. A shutter, disposed between the circuit and the photon receptor, is opened by a controller when the circuit is not energized, and closed by the controller when the circuit is energized. By thus closing the shutter when the circuit is energized, the photon receptor is shielded from receiving the photons generated during the refresh cycle of the energized device, and is able to detect photons from a defect in the circuit over a period of time that is longer than the refresh rate of the circuit.