Abstract: Reflectometry apparatus includes a radiation source, adapted to irradiate a sample with radiation over a range of angles relative to a surface of the sample, and a detector assembly, positioned to receive the radiation reflected from the sample over the range of angles and to generate a signal responsive thereto. A shutter is adjustably positionable to intercept the radiation, the shutter having a blocking position, in which it blocks the radiation in a lower portion of the range of angles, thereby allowing the reflected radiation to reach the array substantially only in a higher portion of the range, and a clear position, in which the radiation in the lower portion of the range reaches the array substantially without blockage.

Abstract: This invention provides a measurement device that includes both an X-ray reflectometer and a thermal or plasma wave measurement module for determining the characteristics of a sample. Preferably, these two measurement modules are combined into a unitary apparatus and arranged to be able to take measurements at the same location on the wafer. A processor will receive data from both modules and combine that data to resolve ambiguities about the characteristics of the sample. The processor can be part of the device or separate therefrom as long as the measurement data is transferred to the processor.

Abstract: This invention provides a measurement device that includes both an X-ray reflectometer and a thermal or plasma wave measurement module for determining the characteristics of a sample. Preferably, these two measurement modules are combined into a unitary apparatus and arranged to be able to take measurements at the same location on the wafer. A processor will receive data from both modules and combine that data to resolve ambiguities about the characteristics of the sample. The processor can be part of the device or separate therefrom as long as the measurement data is transferred to the processor.

Abstract: The present invention provides an improved thin layer nuclear density gauge comprising a gauge housing having a vertical cavity therethrough and a base, a first radiation detector located at a first position within said housing and adjacent to said base of said housing, a second radiation detector located at a second position within said housing and adjacent to said base of said housing, a vertically moveable source rod extending into said cavity of said gauge housing, a radiation source operatively positioned within a distal end of said source rod, at least one bearing operatively positioned to guide said source rod within said cavity, and means for vertically extending and retracting said source rod to a plurality of predetermined source rod positions so as to change the spatial relationship between said radiation source and said first and second radiation detectors. The source rod has a maximum radial movement of less than about 0.003 inch at each predetermined position.

Abstract: A system and method are presented for determining the thickness and elemental composition of a layer within a measurement sample in an easy and inexpensive manner. An embodiment of the method includes impinging an incident x-ray beam into an exposed surface of a measurement sample containing one or more layers. The incident x-ray beam passes through the sample and may refract depending on the composition of the layers to produce a transmitted x-ray beam. The intensity and the angle of refraction of the transmitted x-ray beam may then be measured. These measurements may be compared to the results of a calibration sample that has been prepared with a known thickness and composition relative to the layer characteristics of the sample. The intensity of the transmitted x-ray beam is a function of the thickness of the layer; while the angle of refraction is a function of the elemental composition of the layer.

Abstract: The invention refers to a method for determining the position of an elongated narrow object relative the surface of an obstructing disk-like body in front of said object and oriented at an angle thereto, by means of electromagnetic ionizing radiation, for guidance of the movement of an associated laser welding equipment For providing the carrying out of this method with high speed and greatest precision when manufacturing sandwich elements with conical or double-curved surface it is suggested according to the invention that from the side of the body remote from the object is directed, under approximate movement in the longitudinal direction of the object one precisely collimated radiation beam obliquely to the object under simultaneous scanning motion at right angles thereto, that the radiation back-scattered from the object is collected at the same side of the body and is brought to form a signal which is compared with memory-stored predetermined preference signals for the desired correct position of the obj

Abstract: A system for detecting hidden edges is disclosed. The system comprises a workpiece having a surface and a hidden edge located below the surface. A radiation source moves along the workpiece surface and generates radiation. A radiation receiver moves along the workpiece surface and receives reflected radiation. A processor coupled to the radiation receiver determines a count rate of the reflected radiation, determines a change of the count rate corresponding to the hidden edge, and associates the change to a position on the workpiece surface. A method for detecting hidden edges is disclosed. Step one calls for providing a workpiece having a surface and a hidden edge located below the surface. Step two provides for directing radiation towards the workpiece surface with a radiation source. At step three, the method calls for receiving reflected radiation with a radiation receiver.

Abstract: This invention provides a measurement device that includes both an X-ray reflectometer and a thermal or plasma wave measurement module for determining the characteristics of a sample. Preferably, these two measurement modules are combined into a unitary apparatus and arranged to be able to take measurements at the same location on the wafer. A processor will receive data from both modules and combine that data to resolve ambiguities about the characteristics of the sample. The processor can be part of the device or separate therefrom as long as the measurement data is transferred to the processor.

Abstract: Apparatus for X-ray analysis of a sample includes an X-ray source, which irradiates the sample, and an X-ray detector device, which receives X-rays from the sample responsive to the irradiation. The device includes an array of radiation-sensitive detectors, which generate electrical signals responsive to radiation photons incident thereon. Processing circuitry of the device includes a plurality of signal processing channels, each coupled to process the signals from a respective one of the detectors so as to generate an output dependent upon a rate of incidence of the photons on the respective detector and upon a distribution of the energy of the incident photons.

Abstract: A DEXA bone densitometer produces estimates of future fracture risk from a current fracture data derived from a lateral image of a patient's thoracic and lumbar spine taken in a single scan, typically with the patient on her or his side, and from numerical bone mineral density measurements.

Abstract: The present invention pertains to a non-rotating method for non-intrusively determining the density of a point embedded within an object, without necessarily obtaining a full image for the entire object. The method consists of passing a X-ray beam through a point within an object and measuring Compton scatterings from the point from a first and second energy bands within the energy spectrum of the X-ray beam, along a first and second angles from the X-ray beam. Using the kinetics of Compton scattering at a specific angle, four equations are formulated with four measurements and four unknowns; the radiation attenuation factor along the object between the X-ray source and the point, the radiation attenuation factor between the point and each of the detectors and the density of the object at the point. The four equations are solved simultaneously to determined the four unknowns. There is also provided a matrix inversion process to facilitate the solution of the equations.

Abstract: The present invention provides an in situ, low dose and noninvasive method and device for estimating bone mineral content of trabecular bones, particularly the calcaneus. The method of estimating bone mineral content involves measuring the intensity of X-rays backscattered from the calcaneus and estimating the calcium content from this intensity. In one embodiment the X-ray source is a small x-ray tube that provides a continuous energy spectrum of X-rays. The intensity of backscattered X-rays from the soft tissue covering the trabecular bone, preferably the calcaneus, is compensated for by directly measuring the thickness of the soft tissue. Alternatively the soft tissue thickness can be measured directly along with the bone mineral content from the backscattered X-rays by measuring intensity over an energy range and correlating these results with a model of backscattering from a trabecular bone covered with a layer of soft tissue.

Abstract: Apparatus for X-ray analysis of a sample includes an X-ray source, which irradiates the sample, and an X-ray detector device, which receives X-rays from the sample responsive to the irradiation. The device includes an array of radiation-sensitive detectors, which generate electrical signals responsive to radiation photons incident thereon. Processing circuitry of the device includes a plurality of signal processing channels, each coupled to process the signals from a respective one of the detectors so as to generate an output dependent upon a rate of incidence of the photons on the respective detector and upon a distribution of the energy of the incident photons.

Abstract: A cross-sectional distribution along a cutting plane is derived from an object data set of data values. The cross-sectional distribution comprises density values. The density values are calculated from data values of the object data set in positions outside the cutting plane. The object data set represents an object to be examined and is, for example, acquired by way of volumetric computed tomography or magnetic resonance imaging. For example, the density values of the cross-sectional distribution are calculated by local (slab) MIP or mIP or by interpolation.

Abstract: The thin film deposition system for depositing a thin film on the surface of substrates disposed in a sealed thin film deposition furnace comprises a measuring unit at a site communicating with the thin film deposition furnace, the measuring unit comprising a thin film deposition sample substrate for allowing a thin film substance flowing in from the thin film deposition furnace to adhere while X-ray incidence and extraction windows being provided on the side walls of the measuring unit, wherein X-ray is irradiated on the thin film deposition sample substrate in the measuring unit through the X-ray incidence window by means of a thin film measuring unit provided at the outside of the thin film deposition furnace, and the X-ray reflected from the thin film deposition sample substrate is sensed through the X-ray extraction window.

Abstract: A system and a method for determining the density of an object. The intensity of x-rays backscattered from the object is measured by at least two backscatter detectors disposed at different distances from the intersection of an incident x-ray beam with the plane of the detectors. At least one of detectors is sensitive only to x-rays that have scattered more than once in the object, the ratio of scattered x-rays measured by the detectors being a function of the density of the scattering medium.

Abstract: The present invention provides an improved thin layer nuclear density gauge comprising a gauge housing having a vertical cavity therethrough and a base, a first radiation detector located at a first position within said housing and adjacent to said base of said housing, a second radiation detector located at a second position within said housing and adjacent to said base of said housing, a vertically moveable source rod extending into said cavity of said gauge housing, a radiation source operatively positioned within a distal end of said source rod, at least one bearing operatively positioned to guide said source rod within said cavity, and means for vertically extending and retracting said source rod to a plurality of predetermined source rod positions so as to change the spatial relationship between said radiation source and said first and second radiation detectors. The source rod has a maximum radial movement of less than about 0.003 inch at each predetermined position.

Abstract: The present invention provides a method and apparatus for non-destructive, in situ measuring thicknesses of layers on substrates. The method and device uses a probe including a radioactive source in a source holder and a photodetector mounted behind the source for detection of backscattered photons. In one aspect the method is used to measure the thickness of paint deposited onto metal substrates. The source holder and photodetector array forms a cylindrically symmetric probe for producing an axially symmetric beam of primary photons. A source containing radioactive 109Cd producing high energy photons of energy 22 and 25 keV is spaced from the painted surface so the photons impinge on the painted substrate. The intensity of photons backscattered by Compton scattering in the paint layer is proportional to the mass density of the paint to give a direct measurement of the paint thickness. The photons penetrating through to the substrate are absorbed within the substrate.

Abstract: The present invention provides an in situ, low dose and noninvasive method and device for estimating bone mineral content of trabecular bones, particularly the calcaneus. The method of estimating bone mineral content involves measuring the intensity of X-rays backscattered from the calcaneus and estimating the calcium content from this intensity. The apparatus includes an axially symmetric heavy-metal radioactive source holder (collimator) containing a radioactive source mounted on the axis of a cylindrically symmetric scintillation counter or detector. In a preferred embodiment of the device, a 109Cd radioactive source that emits the K X-rays of silver (22 to 25 Kev) is used. A person's foot is immobilized on the apparatus with a spring-loaded X-ray collimator bearing against the back of the heel. The method relies upon measuring the total intensity of X-rays backscattered from the calcaneus (heel bone).

Abstract: An x-ray diffractometry technique finds thickness of multiple layers of non-metallic crystalline material. A rocking curve is windowed to eliminate a main peak. The windowed curve is smoothed. The smoothed curve is subtracted from the windowed curve to yield a difference curve. The difference curve is transformed to make its average value zero and to constrain its endpoints to zero. A Fast Fourier transform is applied to the transformed difference curve. A thickness transform is applied to the result to yield a layer thickness.

Abstract: A screening system for screening items, such as aircraft-hold luggage, uses a conveyer system for carrying the items along a path and an array of sensors spaced along and around the path for determining the opacity to radiation in planes intersecting the path and the items. A signal processor uses signals from the sensors to detect contours of maximum local rate of change in opacity and from these reconstruct boundaries between the regions having different opacity to radiation and then determines whether or not one or more predetermined screening criteria are met.

Abstract: A method of determining the density profile of a plate-shaped material M, the density of which varies discretely or continuously across the plate thickness, whereas the density at a specific depth of the plate M is preferably assumed to be constant. The inventive method employs X-rays or .gamma.-rays from a source K. The latter source K is placed on one side of the plate M, whereas at least two detectors T, F are arranged on the opposite side of the endless plate being advanced during the measuring in the longitudinal direction. A first detector T is preferably placed in the radiating direction of the source and measures the transmittent radiation through the plate M, and the second detector F is placed outside the radiating direction of the source K and measures the scattered radiation on partial volumes along the radiating direction of the source. Based on the signals measured by the detectors it is possible to measure the density in each individual partial volume.

Abstract: A tomography system for analyzing an object concealed within an enveloping surface. The system has multiple beams of penetrating radiation, each beam disposed with a distinct orientation with respect to the enveloping surface. Detectors are provided for measuring radiation backscattered by the contents of the enveloping surface and for measuring radiation transmitted through the enveloping surface. The enveloping surface is moved with respect to the multiple beams, and a timer provides for measurement of a time difference between the appearance of features in signals of respective detectors, allowing geometrical characteristics of the features to be determined and displayed.

Abstract: A cost effective, field-usable validation and calibration apparatus and method for nuclear density gauges comprises an absorption element, where the absorption element is capable of simulating at least one known density when subjected to analysis using the nuclear density gauge. The absorption element may be positioned inside an enclosure, which also may include an insertion hole capable of receiving a source rod from a nuclear density gauge. The absorption element also can be capable of simulating a plurality of densities, both in backscatter and direct transmission modes. A method of validating and re-calibrating a nuclear density test gauge is also provided, where only a single block of a known density, either a reference block or a field block with a simulated density, is required.

Abstract: The present invention provides a method and apparatus for in situ measuring thicknesses of ice buildup on airfoil. The method and device uses a probe including a radioactive .sup.241 Am gamma ray source producing 60 keV gamma ray photons which penetrate through the airfoil substrate and a photodetector mounted behind the source for detection of backscattered gamma rays. The probe is mounted on the interior of the airfoil and secondary radiation is backscattered within the ice layer and back through the airfoil substrate to the photodetector. The shape and density of the source holder in addition to the geometrical arrangement of the source and detector with respect to the airfoil substrate are used to block a substantial fraction of gamma rays backscattered in the airfoil substrate thereby favoring scattering in the ice layer over that in the airfoil material.

Abstract: A cost effective, field-usable validation and calibration apparatus and method for nuclear density gauges comprises an absorption element, where absorption element is capable of simulating at least one known density when subjected to analysis using the nuclear density gauge. The absorption element may be positioned inside an enclosure, which also may include an insertion hole capable of receiving a source rod from a nuclear density gauge. The absorption element also can be capable of simulating a plurality of densities, both in backscatter and direct transmission modes. A method of validating and re-calibrating a nuclear density test gauge is also provided, where only a single block of a known density, either a reference block or a field block with a simulated density, is required.

Abstract: The present invention provides a method and apparatus for nondestructive, in situ measuring thicknesses of layers on substrates. The method and device uses a probe including a radioactive source in a source holder and a photodetector mounted behind the source for detection of backscattered photons. In one aspect the method is used to measure the thickness of paint deposited onto metal substrates. The source holder and photodetector array forms a cylindrically symmetric probe for producing an axially symmetric beam of primary photons. A source containing radioactive .sup.109 Cd producing high energy photons of energy 22 and 25 keV is spaced from the painted surface so the photons impinge on the painted substrate. The intensity of photons backscattered by Compton scattering in the paint layer is proportional to the mass density of the paint to give a direct measurement of the paint thickness. The photons penetrating through to the substrate are absorbed within the substrate.

Abstract: The present invention provides a method and apparatus for in situ measuring thicknesses of ice buildup on airfoil. The method and device uses a probe including a high energy radioactive gamma ray source .sup.241 Am producing 60 keV photons which penetrate through the airfoil substrate and a photodetector mounted behind the source for detection of backscattered photons. The probe is mounted on the interior of the airfoil and secondary radiation is backscattered within the ice layer and back through the airfoil substrate to the photodetector. The shape and density of the source holder in addition to the geometrical arrangement of the source and detector with respect to the airfoil substrate are used to block photons backscattered in the airfoil substrate thereby favoring scattering in the ice layer over that in the aluminum.

Abstract: A film thickness measuring method comprises the steps of measuring reflectances of X-rays on a film, extracting interference oscillations from the measured X-ray reflectances, and Fourier transforming the interference oscillations to compute a film thickness of the film, an average reflectance being given by fitting the measured X-ray reflectances to an analysis formula including a term of a product of a power function of an incident angle, which expresses attenuation of reflectances on a smooth surface of the film and an exponent function which expresses influence of roughness of the surface of the film, and a constant term expressing a background added to the product; the interference oscillations being given by using the measured X-ray reflectances and the average reflectance. The film thickness measuring method can extract interference oscillations of a reflectance curve by a method including arbitrariness and by a simple procedure.

Abstract: An x-ray backscatter tomography system includes a collimated x-ray source for directing a collimated beam towards a target at a select position and orientation, a first detector array for measuring photons scattered at a selected first angle, and a second detector array for measuring photons scattered at a selected second angle different from the first angle. The system is also responsive to the first and second detectors for calculating the density and atomic number of the target.

Abstract: A thickness measurement gauge for measuring the thickness of an object. The gauge has a closed housing having a radiation-permeable housing floor. Within the housing are disposed (1) a radiation shield that houses a radiation source; (2) a radiation detector for detecting backscatter rays; and (3) a light sensor optically coupled to the radiation detector through a light guide also disposed within the housing. The shield has a collimation channel within which is the radiation source emitting gamma rays that exit the channel as a collimated beam. The light sensor converts light pulses from the radiation detector to electronic signals that are transmitted to an electronic readout device for conversion into a reportable thickness measurement. Measurement is accomplished by positioning the housing floor adjacent the surface of an object to be measured such that the gamma rays passing through the floor enter entry into the object.

Abstract: A method of evaluating bone density around a radiolucent composite prosthesis establishes an implant boundary by fitting a stored template to radio-opaque reference markers embedded in the prosthesis. The implant boundary is used to create a measurement boundary displaced from the implant boundary toward the bone producing a conformal region of interest. Matched histograms of bone density in a lateral and medial such region of interest may be displayed to evaluate symmetrical stress effects. Alternatively, bone density may be displayed plotted along an axis cutting across the medial and lateral sides. Fiducial points are identified from the bone and implant morphology to ensure that either display will have a repeatable reference and hence that such displays will be directly comparable to later and earlier displays thereby aiding in the detection of bone change.

Abstract: Radiometric gage for contactless measurement of the surface density or the thickness of a flat product, includes:an X-radiation emitter, whose tube, is directed toward the flat productan X-radiation receiver, whose detector is disposed in order to receive X-radiation scattered or transmitted in attenuated form through said flat product, said receiver delivering a measurement signala member for processing the measurement signal, in order to obtain information representing the surface density or the thickness of the flat productThe anticathode of the tube is made of a material with atomic number as high as possible, preferably greater than 70, which is a good conductor of heat and has a high melting point.

Abstract: A radioactive source holder for use with a NaI (TI) spectrometer for obtaining very low dose estimates in bone minerals in vivo, comprising a molybdenum tube, a gold insert within the tube, a blind hole within the insert for receiving the radioactive source, and an inner tube inserted into the blind hole for directing radiation from the source in a narrow cone, whereby the directing of radiation in the narrow cone minimizes spectrometer response to radiation which has been scattered by soft tissue overlying a bone.

Abstract: An apparatus for providing assessment indices related to bone strength which are useful in predicting the risk of bone fracture. The apparatus measures the mineral density of bone (BMD) by means of X-rays, while the propagation speed of sound V in the bone and bone thickness d are measured by means of ultrasonic waves. The bone mineral content per unit volume, i.e. the bone volume density .rho., is computed from the bone mineral density (BMD) and the thickness of the bone. An assessment value E is then computed based on V and .rho..

Abstract: A scintillation camera comprises a camera body for detecting a .gamma.-ray emitted from radioisotope provided to a human body to be examined in a predetermined period of time, means for measuring an incident position of the .gamma.-ray and its density based on the detection result of the camera body, and means for generating a density distribution of the .gamma.-ray for every incident position based on the measurement result of the measuring means, thereby obtaining the density distribution of the .gamma.-ray for every incident position.

Abstract: The method and apparatus for logging the media of an earth formation wherein repetitive bursts of x-rays are emitted that penetrate the media with a portion of these x-rays to be scattered and picked up by a plurality of detectors to detect certain physical properties of the media such as density and lithology. The x-rays are produced by an electron beam striking an x-ray target. This electron beam is produced electrically within an electron beam generator and then accelerated through a linear induction accelerator. The linear induction accelerator, in contrast to other alternatives, is of simple design and inherently insensitive to mechanical shock and vibration and to variations in operating temperature.

Abstract: In x-ray fluorescence systems, the screening prevents the bringing of the measurement spot into the correct position in relation to the x-ray beam using the naked eye. The use of a television camera with a screen as well as illuminating devices makes the measuring system expensive and complicates the use of the system. According to the invention, this is avoided in that use is made of an illuminated device, which operates using an optical system and which reproduces, by convergent light beams at their intersection, the correct height position, lateral position and forward/rearward position of the measurement object when the tray carrying the measurement object has been moved to a forward position away from the x-ray beam.

Abstract: A method of evaluating bone density around a prosthesis establishes an implant boundary at the edge of the prosthesis and creates a measurement boundary displaced from this implant boundary toward the bone producing a conformed region of interest. Matched histograms of bone density in a lateral and medial such region of interest may be displayed to evaluate symmetrical stress effects. Alternatively, bone density may be displayed plotted along an axis cutting across the medial and lateral sides. Fiducial points are identified from the bone and implant morphology to ensure that either display will have a repeatable reference and hence that such displays will be directly comparable to later and earlier displays thereby aiding in the detection of bone change.

Abstract: A microbalance and method for measuring the total mass of small quantities of material (mass ranging from about 10 nanograms to about 0.1 gram) using Compton and Rayleigh scattered radiation provides excellent mass measurements for these samples. The apparatus includes a standard radiation generation and detection assembly, including a substantially evacuated chamber through which incident radiation travels, and commercially available radiation generators, power sources, and detectors, having enough spectral resolution to identify the scattered radiation of interest.

Abstract: A highly reliable apparatus and method of measuring bone mineral density and bone strength simultaneously is provided. Pleochromatic X-rays emitted from an X-ray tube are incident upon an object to be measured. Transmitted X-rays and diffracted X-rays, generated during the time period when the X-rays are passed through the object, are separately detected to simultaneously measure the bone mineral density and the bone strength.

Abstract: The invention provides an inspection system for closed containers, such as luggage, which applies radiant energy, such as x-rays, to a container and receives energy which is scattered, such as by Compton scattering, by objects in the container. The received energy is measured and a three-dimensional image of the objects in the container is constructed. The container may be moved relative to a fan-shaped primary x-ray beam, which illuminates a single slice of the container at a time. For example, the container may be moved by a conveyer belt, or, the container may be held stationary while the x-ray tube may comprise a steerable beam. A plurality of collimated x-ray sensors may receive energy which is scattered, at a fixed angle for each sensor, and transmits those measurements to a processor which reconstructs the three-dimensional image and displays that image for an operator.

Abstract: A method and a system for enabling high accuracy measurements to be obtained of the location of a plane separating two media of different densities by using the Compton effect, and application thereof to measuring the thicknesses of layers. A measurement assembly constituted by a transmitter and a receiver of X-rays or gamma rays which are focused in emission and in reception irradiates an elementary volume of said media, and is displaced perpendicularly to the plane between said media, and a fifth signal is calculated representative of the extent by which the derivative of the detected signal relative to the displacement exceeds a threshold, after which the barycenter of displacements corresponding to the most recent sequence of said same-sign fifth signals is calculated, with the displacements being weighted by the corresponding one of said fifth signals.

Abstract: A method for using secondary radiation scattering to evaluate the thickness of materials. The thickness of a first material adjacent to a second material may be evaluated by bombarding the first material with radiation and measuring the radiation scattered by the second material behind it. The method is particularly useful in evaluating the thickness of hydrocarbon-carrying pipelines.

Abstract: A method and apparatus for measuring, for example, the iron content in zinc layers and/or the thickness of a layer of zinc in galvanized steel. In order to measure the percentage of iron content in a zinc layer, the apparatus has a source of X-radiation which is arranged at a specified angle to the plane of the material to be measured and at least two detectors equipped with selective sensitivity, one of which is arranged at a second angle and the other at a third angle. One detector measures the iron content and the other detector measures essentially the amount of zinc per unit surface of the coating. From these two measurements, the amount of iron as a percentage of the zinc layer can be calculated.

Abstract: A distance between a radiation source and a detector is first set to a first distance and the number of pulses of a .gamma.-ray is detected. Then, the distance between the radiation source and the detector is set to a second distance different from the first distance and the number of .gamma.-ray pulses is detected. A density .rho. of a sample is finally calculated on the basis of a ratio of the two detection pulse numbers which were detected. The radiation source is set on the surface of the sample or in the sample. The sample detector is set on the sample surface. Fundamentally, one radiation source and two detectors are used. In the case of using one radiation source and one detector, either one of them is moved and the number of pulses is detected twice.

Abstract: A Compton x-ray backscatter gage apparatus directing x-rays from an isotopic radiation source to a region of interest in a composite structure to monitor structural integrity. The backscattered x-rays from the region of interest are directed by guides in the gage housing to radiation detectors.

Abstract: A method and apparatus for measuring simultaneously the thickness and the composition of a coating on a metal substrate. A first beam of radiation that produces a primary beam of photons is directed substantially perpendicularly to the surface of the coating. A first detector is positioned substantially perpendicularly to the surface of the coating to receive a first fluoresced beam. The photons having a first energy level representing a higher concentration element of the coating are selected. A first electrical signal is provided that is a function of the intensity of the photons having the first energy level. A second beam of radiation producing a second primary beam of photons is directed at an acute angle to the surface of the coating. A second detector is positioned substantially perpendicularly to the surface of the coating to receive a second fluoresced beam. The photons having a second energy level representing a lower concentration element of the coating are selected.

Abstract: A cable insulation eccentricity and diameter monitor comprises a revolving structure mounted coaxially with the cable, a finely collimated source of gamma particles mounted on such revolving structure for generating a beam of gamma particles, a radiation detector fixed to the revolving structure for detecting the gamma particles scattered from such beam by the cable and for generating pulses the amplitude of which is dependent on the energy of the scattered gamma particles reaching the detector, first drive means for moving the source of gamma particles so as to direct the beam at predetermined target positions corresponding to probable conductor and cable/atmosphere boundaries of the cable along a first axis perpendicular to the axis of the cable, second drive means for repositioning the revolving structure to move the source of gamma particles and the radiation detector to a position around the cable so as to direct the beam at target positions corresponding to probable conductor and cable/atmosphere bounda

Abstract: This invention provides a method used for radiographic inspection of matel within a container, where the container is a dense material and the contents to be radiographically inspected are of a less dense material.