Abstract: A VHF television tuner circuit is adapted for selecting a channel from a plurality of VHF television channels and a UHF/VHF converted television channel, by mechanical selection to form a resonant circuit having electrical characteristics corresponding to the selected channel. The tuner circuit is coupled to a VHF television signal terminal and a UHF/VHF converted television signal terminal. The tuner circuit comprises a channel selection means including a first switch and a second switch each comprising movable contacts fixedly positioned on a channel selection shaft and stationary contacts corresponding to the selectable channel positions and positioned in proximity to the movable contacts for coaction therewith. The first switch comprises a movable/stationary contact combination positioned in the vicinity of the VHF television signal terminal and responsive to selection of the UHF/VHF converted channel position for being grounded for electrostatically shielding the VHF television signal terminal.

Abstract: An interactive computer controlled asymmetric texture-sensitive parafocussing X-ray powder diffractometer employs an incremental rotating specimen device which permits azimuthal rotation (through the angle .phi. of the disc-shaped specimen about its surface normal. The rotating specimen device, rotatable about the principal diffractometer axis, can be offset an angle .alpha. from the symmetric position in which the specimen surface normal makes the angle (90-.theta.).degree. with both the source-to-specimen and detector-to-specimen directions. In order to maintain the Brentano focussing condition, the photon-counting detector is supported on a slide which is translated towards or away from the specimen by a stepper-motor drive lead screw. K, the ratio of the detector-to-specimen and x-ray source-to-specimen distances is constrained to the specified range c<K<f, where c is the smallest and f the largest ratio achieved. The focussing condition is realized by computer control which maintains K=sin (.theta.

Abstract: An X-ray table comprising a body having end, front and rear side members formed of inside and outside skin members having parts thereof spaced from one another and connected together by reinforcing members welded to the skin members and a method of making such a table. According to the method the side members are constructed as subassemblies with the inside and outside skin members of the end and front sides merely welded at their upper edges. Subsequently the vertical side members of the table body are assembled in a fixture without stress in the sheet metal parts. The outside members are then welded together at the junctures thereof. Finally the inside skin members of the end side members are welded to the reinforcing members previously welded to the end outside skin members and the front inside skin members is welded to the reinforcing members.

Abstract: An X-ray table of the tiltable type in which a tower assembly is movably carried by a table body. The tower assembly includes a mast or column that is carried by a carriage and movable relative to the carriage in a path transverse to the longitudinal extent of the table. The carriage is longitudinally movable relative to the table body. The carriage support is provided by cylindrical ways and bearing clusters each including four circumferentially spaced bearings that are arranged in diametrically opposed pairs. One bearing of each pair is eccentrically mounted for preload adjustment. The bearings of one pair are positioned such that their axes are perpendicular to the plane of resultant forces imposed on the bearings and the ways when the table is in a vertical orientation.

Abstract: An X-ray photographing apparatus includes an X-ray tube for generating an X-ray pulse beam, a shutter for shutting off the X-ray pulse beam which is emitted from the X-ray tube, and a shutter controller for permitting the X-ray pulse beam shut off by the shutter to be passed therethrough when the intensity of the X-ray pulse beam from the X-ray tube reaches a substantially constant level. The apparatus permits the subject to be exposed at all times with a stabilized intensity of X-ray beam.

Abstract: There is disclosed herein an aspheric grating which is operable to image local or distant point sources sharply in a designated wavelength, i.e. produce a perfectly stigmatic image in the given wavelength at grazing angles of incidence. The grating surface comprises a surface of revolution defined by a curve which does not have a constant radius of curvature but is defined by a non-linear differential equation specified in terms of the diffraction condition expressed as (m.lambda./.sigma.).sup.2 =A>O where m is the diffraction order, .lambda. is the wavelength and .sigma. is the grating surface ruling interval.

Abstract: A circuit for use with a X-ray tube applies filament power to preheat the tube prior to the application of high voltage. The preheat duration is made to be in inverse relation to the line voltage. The desired result is when the tube starts to conduct the tube current and tube voltage is held within acceptable limits regardless of line voltage variations.

Abstract: An improved method for computed tomographic scanning is disclosed. A beam of electromagnetic radiation subtending an angle .phi. is alternately translated and rotated past a patient. The intensity of the beam is detected by an array after the radiation passes the patient and a reconstructed image created from the detected intensities. Each rotation of the array is through an angle less than the angle .phi. subtended by the array producing redundant intensity readings for similarly oriented beam paths through the patient. This redundant intensity data is modified according to a scheme which tends to reduce motion and misalignment artifacts within the patient.

Abstract: An X-ray apparatus, comprising a weight compensation device which is suspended from the ceiling and which includes a carriage which is displaceable along the ceiling. A component is displaceable along a patient table is suspended from the carriage by means of a cable. A signal from a transducer is applied to an electric motor which drives the carriage compensate for the relative displacement between the carriage and the suspended component.

Abstract: Process and apparatus for providing an imaging gas under pressure to the imaging chamber of an electron radiographic system. After closing the imaging chamber, air is flushed out by introducing a condensable gas such as a Freon. The Freon is then flushed out by a charge of the imaging gas, such as xenon and krypton. The exhausted air-Freon mixture is collected and pressurized to condense and separate out the Freon from the air. The liquid Freon is then expanded into a gas and used for a subsequent flushing step. Similarly, the exhausted Freon-zenon mixture is retained and pressurized to liquify and separate the Freon from the xenon. The liquid Freon is expanded to a gas and used for a subsequent flushing operation and the xenon is used for a subsequent charge into the imaging chamber. After an exposure, the imaging gas is flushed out with Freon and the chamber may then be opened.

Abstract: X-ray lithographic systems as heretofore constructed include a low-attenuation chamber for propagating x-rays from a source toward a mask member that is positioned in close proximity to a resist-coated wafer. Both the mask and the wafer are included in the chamber which typically is either filled with helium or evacuated to a pressure less than about 10.sup.-2 Torr. In accordance with this invention, an x-ray lithographic system is constructed to enable establishment in the wafer-to-mask region of a controlled atmosphere that is separate and distinct from that maintained in the low-attenuation chamber. In this way, an improved lithographic system with advantageous throughput and other characteristics is realized.

Abstract: Apparatus for admitting sheets of unexposed X-ray film into and for removing sheets of exposed X-ray film from cassettes of the type having two pivotally connected sections which are separably locked to each other has a housing with a wall which is pivotable to and from an open position in which a cassette containing a sheet of exposed film is inserted into the housing so that one of its sections lies against a pivotable partition while the latter assumes a first position to thereby seal a cassette-receiving first compartment from a second compartment of the housing. A mechanism is actuated in the closed position of the wall to unlock the cassette in the first compartment and to hold the other section of such cassette against movement with the partition. The partition is thereupon pivoted to a lowermost position, together with the one section of the cassette, so that the exposed sheet can descend by gravity into a tray in the second compartment.

Abstract: Latent images which are formed on dielectric receptor sheets during exposure to object-modulated primary and stray X-rays, while the sheets dwell in the interelectrode gap of an ionography imaging chamber, are developed in an electrophoretic unit which neutralizes the effect of stray radiation upon the receptor sheets so that the developed visible images are reproductions of those portions of latent images which are formed as a result of exposure to primary radiation. The neutralizing involves ascertaining the intensity of stray radiation behind the imaging chamber by resorting to one or more dosimeters and one or more rasters or analogous devices which absorb stray radiation, and applying to the electrodes of the developing unit a reverse potential which is proportional to the intensity of stray radiation. Alternatively, the intensity of stray radiation can be ascertained empirically and the reverse potential is selected by hand, depending on the density and thickness of the object.

Abstract: Radiation from an intraoral source which travels arcuately within the patient's oral cavity is collimated with camera slot of a panoramic dental X-ray machine to thus obviate the need for the X-ray tube head and shifting of the patient.

Abstract: A process for the nondestructive testing of ceramic objects to detect the presence of defects and micro-cracks in the surface in which a solution of silver nitrate is applied to the surface of the object which penetrates into the surface defects, drying the object so that the silver nitrate remains in the defects, and preparing an X-ray radiograph whereby any defects and micro-cracks will appear in the radiograph.

Abstract: In a computerized tomographic apparatus in which the source and detectors are moved angularly around the body, the angular movement of the source is, in effect, periodically arrested so that the detectors, which are of greater angular extent than the distribution of radiation produced by the source, slide through the distribution. In this way successive detectors can be made to view the same beam in the distribution.

Abstract: An electrical energy regulator, particularly suitable, for a portable X-ray machine. A transformer primary of a converter is supplied with half waves of a.c. via a transistor whose conduction interval during each half-wave is controllable to regulate the peak voltage applied, after cut off of primary current, by induction from a tuned circuit formed with the primary to an X-ray tube connected to a secondary winding of the transformer.

Abstract: X-ray fluorescence produced by a primary X-ray beam incident at a very flat angle (below 1.degree.) onto the surface of a specimen contained in a vacuum chamber is used to analyze shallow layers and/or to determine depths of shallow surface layers, such as a very thin (typically between about 10A and 10.sup.3 A) silicon coating on Al or Cu layers which overlay a silicon substrate. Semiconductor profile determination may be another application of the invention.

Abstract: A method and apparatus is provided for determining in a non-destructive manner the quantities of components in a material having irregular surfaces and which may be of a non-uniform size and of a variable consistency. Three or more beams of polychromatic X-rays, each at a different level of energy, are passed through the material, and the measurements of each incident beam and each transmitted beam are utilized in determining the percentage of one or more of the components after having substantially eliminated so-called beam-hardening effects which otherwise limit the utility of polychromatic beams.

Abstract: Tubular electromagnetic components are mounted on the drive shaft of the ary anode of an X-ray tube and external magnet windings are provided both for maintaining the drive shaft in an axial position corresponding to a working position of the anode and for shifting the drive shaft to open a slip contact at one end thereof, thus providing a magnetic switch for the anode supply voltage. In addition, windings are provided through which a controlled current flows to provide a radially stabilized position for the shaft and thus constitute magnetic bearings that are free of friction. When one of the contacts of the magnetic switch is spring-mounted, the coil that does the switching can also be used to adjust the axial position of the anode so as to work with a different cathode.