Abstract: The invention provides an apparatus and method for monitoring the electrical conductivity of a web surface in which a forwardly moving web is exposed to an electrical field generated by a forwardly extending high voltage source so disposed adjacent the web as to induce a transverse redistribution of the electrical charges present on the web surface, the electrical field signal generated by the redistributed surface charges of opposite polarity to that of the source being monitored by a suitable field detector.

Abstract: This invention relates to an X-ray system including an ion chamber for monitoring and controlling the amount of radiation delivered to the X-ray film.

Abstract: A programmable number of pulses N, of one or more auxiliary frequencies fa, is inserted between pulses of the frequency f.sub.1 to be processed. The resulting frequency N.f.sub.1, where N is a positive number (N can be fractional), is at any moment proportional to input frequency f.sub.1 where N, the proportionality factor, varies at will and can assume any positive number value. Pulse insertion results in a frequency shift of positive or negative value and succeeds continuously and without any information loss i.e. the pulse train has not to be interrupted and is processed "on (the) line". The same method described used for higher frequencies eliminates the known .+-.1 count problem as it can register fractions of a pulse.

Abstract: This invention relates to a nondestructive method for measuring the density of articles composed of elements having a low atomic number such as plastic and carbon composites. The measurement is accomplished by striking the article with a collimated beam of X radiation, simultaneously monitoring the radiation scattered and the radiation transmitted by the article, then relating the ratio of the radiation scattered to the radiation transmitted with the density of the article. The above method is insensitive to all variables except density.

Abstract: An arc-shaped X-ray beam penetrates an arcual cross-sectional area of a body and the attentuated transmitted beam irradiates a portion of a circular array of detectors on a rotating disc. The detectors operate to generate signals proportional to the intensity of the incident transmitted radiation. The beam and detectors are moved along the axis of the body during rotation of the disc to irradiate adjacent cross-sectional areas of the body. A computer operated CRT receives the detector signals and displays an image of the radiation attentuation characteristics of the scanned arcual areas.

Abstract: X-ray generation and detection apparatus for use in a computer assisted tomography system which permits relatively high speed scanning. A large X-ray tube having a circular anode (3) surrounds the patient area. A movable electron gun (8) orbits adjacent to the anode. The anode directs into the patient area X-rays which are delimited into a fan beam by a pair of collimating rings (21). After passing through the patient, X-rays are detected by an array (22) of movable detectors. Detector subarrays (23) are synchronously movable out of the X-ray plane to permit the passage of the fan beam.

Abstract: In an exemplary embodiment an inverter manifests a circuit for the alternate connection of the terminals of an LC oscillatory circuit with the poles of a d.c. voltage source. The primary winding of the high voltage transformer is connected in series with the capacitor to form the LC oscillatory circuit. By this means, a short-circuit proof state of the inverter results.

Abstract: A control system for rotating anode x-ray tubes comprising an x-ray tube including an anode rotated by a motor having mounted therein photoelectric means for sensing rotational movement of the anode, and circuit means electrically connected to the tube, the photoelectric means, and the motor for regulating operation of the tube and rotational speed of the motor in accordance with parameters selected for operation of the tube.

Abstract: A method of and apparatus for producing texture topograms at surface layers of non-amorphous polycrystalline bodies comprises means for producing a divergent beam of monochromatic radiation. The divergent monochromatic radiation beam is diffracted at a polycrystalline body to be examined. Slit-shaped apertures are arranged in the radiation path of the diffracted radiation and extend parallel to the diffraction plane. Means for forming an image of the picture of the diffracted radiation are arranged behind the slit-shaped apertures and at a distance from the surface of the polycrystalline body and the focussed reflex.

Abstract: In the illustrated embodiment, an electron collimator is to be mounted on the accessory holder of an electron accelerator. In radiation therapy, the down beam end of the applicator is to contact the patient to establish a precise spacing of the electron source therefrom. The legs of the L-shaped collimator plates have rods secured to the corner part thereof which link pairs of overlapping legs to a common carrier for joint lateral adjustment toward and away from the beam axis. The rods slide in apertures in the carrier as the legs are adjusted longitudinally. Cornered wall elements are secured to each collimator plate and overlap each other to surround the beam path, and have in-turned closely overlapping edges which terminate flush with the inner margins of the collimator plates so as to provide further electron collimation and to provide an essentially smooth patient contacting end face.

Abstract: A dual mode band rejection filter for attenuating electromagnetic energy in a predetermined stop band having at least one resonant cavity with a pair of orthogonally related modes of propagation. The energy is propagated through a waveguide coupled to ports in the cavity. The waveguide has an input section coupled to a first cavity port, an intermediate section coupled between the first and second ports of the cavity and an output section coupled to the second port. The length of the intermediate section provides a predetermined phase shift between the first and second ports. The filter may include another dual mode resonant cavity coupled to the waveguide by additional waveguide sections.

Abstract: In an exemplary embodiment, two inverters of which each exhibits a switching installation controlled by a control circuit for the alternate connection of two output lines with the power rectifier. The control signals supplied to the inverters by the control circuit are out of phase with one another, so that the x-ray tube voltage possesses a low ripple component.

Abstract: A detector for detecting the presence of selected frequency components of an input signal and operative to deliver output responsive thereto by providing two separate signal paths in the detector, at least one path including filter circuitry having a distinct cross-over point operative to pass frequencies on one side of the cross-over point with one phase relative to the input and to pass frequencies on the other side of the cross-over point substantially 180.degree. out of phase relative to the input, and the detector further including a coincidence circuit receiving the signals from the two paths and generating one level of output for signals which are substantially in phase and generating another lower level of output for signals substantially out of phase. The coincidence circuit may have provisions for establishing an input threshold level which the signals must overcome.

Abstract: A tuning device including a conductive housing in which is suspended a dielectric substrate. A pair of first and second resonant circuits is disposed on the substrate in parallel with each other. Each resonant circuit is formed by an elongated conductive film and a capacitive element. An image frequency trapping circuit is arranged to intersect one of the transmission lines to absorb the signal at the image frequency. A grounded conductive strip film is provided adjacent to and parallel with each of the transmission lines and so spaced therefrom that the characteristic impedances of the transmission lines are made equal to each other.

Abstract: A tuning circuit comprises a pair of identical resonant circuits each including a transmission line and a capacitive element, a coupling circuit associated with each transmission line to inject microwave energy into the resonant circuits and extract the tuned energy therefrom. An image trapping circuit is included which comprises a first section which intersects one of the transmission lines and connected to the coupling circuit associated with the intersected transmission line and a second section which extends from the point of connection of the first section with that coupling element to the opposite transmission line in a direction skewed relative to each transmission line. The second section of the image trap circuit provides a smooth interstage coupling between the two transmission lines over a range of resonant frequencies.

Abstract: A method and circuit arrangement for improving the definition of the focal spots of X-ray tubes which comprises periodically varying the bias voltage applied to the concentrating electrode of the tube, focalizing the eletron beam emitted by the filament, between a negative minimum or zero value and a negative maximum value, with a voltage waveform whose frequency is higher than 10 kilohertz, wherein this bias voltage has to assume at least the two extreme values frequently, while a direct-current high voltage is being applied between the cathode (filament) and the anode (target) during the exposure time.

Abstract: In an exemplary embodiment, an inverter manifests a load output which is capable of being alternately connected, via a switching apparatus with the poles of a d.c. voltage source. Changeover switches are present by means of which the load output can be selectively connected between a midpoint conductor of the d.c. voltage source and the midpoint of a half-bridge formed by the switching apparatus, or into the diagonal of a full-bridge formed by the switching apparatus. The changeover switches for the formation of the half-bridge, parallel-connect two branches of the full-bridge in each instance. By this means, the inverter is capable of being adapted selectively to a high voltage or a high current load.

Abstract: An x-ray receptor is translatable in x and y directions relative to the angulation axis of an x-ray source. Servo motors angulate the source and receptor coordinately with translation so the central ray of the x-ray beam from the source will be perpendicular to the input plane of the receptor when an x-ray exposure is made. New circuitry prohibits making an exposure until the source and receptor are properly angulated. Potentiometers develop signals corresponding with x and y distances and these are divided to get a servo motor command signal corresponding with the tangent of the angulation angle .theta.. Potentiometers driven coordinately with the receptor and source produce respective sets of signals corresponding with true instantaneous or real time angles .theta. and tangent .theta.. The first tangent .theta. command signal is continuously compared with the other tangent .theta. signals and the first tangent .theta. signal is independently compared with the actual angle .theta.

Abstract: Film changers used in biplane radiography are provided with shields having radiolucent and radiopaque sections which are alternately disposed in front of the x-ray film presented by the film changers for exposure. Operation of the two shields is synchronized to dispose the radiopaque portion of one shield in front of one changer when the radiolucent portion of the other shield is disposed in front of the other changer such that scattered radiation cannot reach film in the one changer and fog it when an image is being recorded by the other changer. In one disclosed embodiment of the invention, the shield is a flexible endless belt with alternating radiopaque and radiolucent sections mounted for rotation in a loop around the film changer. In a second disclosed embodiment of the invention, planar discs having alternating radiopaque and radiolucent sectors are rotated in front of the film changers.

Abstract: A half-wave rectifier is connected between the cathode-side end of the secondary winding of the high voltage transformer and the x-ray tube anode. Between the anode and the anode-side end of the high voltage secondary winding, a high voltage capacitor is connected, which is capable of storing a portion of the energy necessary in order to feed the x-ray tube during one mains half wave. The rectifier is polarized such that the capacitor is charged during those particular secondary half waves in which current does not flow through the x-ray tube.