General Electric Company

Electric Power Research Institute Incorporated

John M Houston

Nathan R Whetten

James R Young

Harry R Summerhayes

Electronic equipment and the like, particularly electronic equipment used in oil well logging, is kept cool by placing it in a container inside a vacuum dewar filled with a vaporizable fluid such as water. As the water evaporates, it removes heat from the dewar. The water vapor is absorbed inside a canister filled with a water-absorbing material. A thermostatically-controlled valve is provided to limit water vaporization when not required for cooling, thus greatly extending the life of a single charge of cooling fluid.

Apparatus for maintaining electronic equipment and the like at low

A long-life cesium lamp is disposed within an evacuable outer envelope surrounding a cesium lamp arc tube with their respective surfaces spaced a fixed distance apart so that a heat-transferring gas, such as helium, is disposed between the arc tube and the wall of the outer envelope. Furthermore, means are provided for cooling the outer envelope, such as by surrounding it with a water jacket. The resulting lamp system is capable of operating at higher levels of average lamp power and arc tube wall loading (watts/cm.sup.2) without causing too low a cesium pressure, as would happen if one directly water-cooled the alumina arc tube, and without causing too high an alumina arc tube temperature, as would happen if one merely evacuated the outer envelope. The lamp system of the present invention is also employed in a housing in which the lamps are disposed along the foci of a dual-elliptical cavity so that light emissions from the lamps are focussed upon a slab of lasing material, so as to form, for example, a neodymium-YAG laser.

High power cesium lamp system for laser pumping

In high voltage vacuum interrupters and similar devices, it is desirable to provide some indication that vacuum conditions within the containment vessel have degraded . Advantage is taken of the fact that metallic barium forms a substantially opaque and reflective film but that barium oxide, formed as a result of air penetrating the vacuum, forms a nonreflective and substantially transparent film. In the present invention, a housing is provided with means for attachment to the vacuum vessel with the housing having at least one light-transmissive portion. A barium film is disposed on at least one of these light-transmissive portions and means for detecting changes in the optical characteristics of the barium film are also provided. In this way, degradation in vacuum condition, evidenced by oxidation of the barium film, results in a signal indicating that contamination of the vacuum condition has occurred.

Apparatus and method for detecting the loss of vacuum

The leading edge of the plates employed in a high pressure gaseous xenon x-ray detector are tapered so as to be narrower along the edge of the plates nearest to the x-ray source. Xenon x-ray detectors produced in accordance with the present invention exhibit an increased quantum detection efficiency without a significant increase in noise due to microphonics.

Xenon x-ray detector with tapered plates

A high pressure, high resolution xenon x-ray detector array employs a housing having a window therein for passage of x-rays from an x-ray source and sealed to form a detection chamber. A voltage plate and a collector plate are disposed in the detection chamber in parallel relationship and passed through the housing to outside contacts. Xenon is disposed within the chamber with a pressure range of 50 to 200 atmospheres producing a xenon density in the range of 0.5 to 2.5 grams per cubic centimeter.

High pressure, high resolution xenon x-ray detector array

An x-ray source for use in computerized tomographic applications focuses an electron beam on an arcuate anode ring to produce an x-ray beam which passes through a planar slice of the subject under study. Electromagnetic focusing and directing of the electron beam acts to produce the same effects as those produced by a single x-ray source which is mechanically rotated about the patient. Because it is very difficult to focus and to bend an electron beam having a cross section with other than cylindrical symmetry, and because it is highly desirable that the cross section of the electron beam have a rectangular cross section as it impinges upon the anode, an electromagnetic means is disposed adjacent the electron beam path between the anode and the beam bending coils to oscillatorily deflect the beam so that it effectively exhibits a substantially rectangular cross section, the long dimension of the rectangle always pointing toward the system axis. This configuration permits either a more intense x-ray source or, alternately, an x-ray source with a smaller projected spot size.

Electronically scanned x-ray tomography system

An x-ray fan beam is caused to impinge upon an object, such as airport luggage or jars of food, as the object moves translationally through the fan beam; after passage through the object, the x-rays are made to impinge upon an x-ray transmissive detector housing containing a gaseous detecting medium, a power electrode and a plurality of signal electrodes. The power electrode and the signal electrode are maintained at different voltage levels so that electrons and/or ions generated by the interaction of the gaseous detecting medium and the x-rays, drift toward the electrodes thereby producing an electrical current which can be sensed, analyzed, and used, for example, to generate an image or to indicate the presence of foreign matter.

Scanning x-ray inspection system

A time-of-day watt-hour meter shifts sensitivity whenever the utility transmits an audio tone over the power line to the watt-hour meter. Via an integrated circuit receiver, the tone causes a solid state switch to close, thus increasing the meter sensitivity by increasing the effective number of turns of a voltage coil across the 240 volt line. The effective sensitivity of the meter can be adjusted as desired by varying the duty cycle of the tone transmitted over the power line.

Method and apparatus for tone controlled variable sensitivity

A saturable magnetic reactor is disposed about one of the current-carrying conductors in a DC power transmission line. A zero-current status for the transmission line is sensed by means of impedance changes in the reactor. A step-down transformer cascade electromagnetically couples the saturable reactor to impedance detection means, which means typically comprise an oscillator driven bridge circuit.

Zero-current detector for high voltage DC transmission line

A solenoidal electric field lamp comprises a plurality of toroidal ferrite cores connected to a radio frequency energy source and disposed in an ionizable gas. The cores are so connected and oriented that circulating discharge currents passing through each core produce magnetic dipole fields which tend to cancel one another. Near and far field electromagnetic interference is thus reduced even when the lamp is operated at higher, more efficient frequencies. The cores are disposed in a variety of configurations.

Solenoidal electric field lamp with reduced electromagnetic interference

A high speed tomographic x-ray imaging system comprises an array of x-ray sources disposed opposite a closely spaced array of x-ray detectors. Small groups of sources in the array are simultaneously pulsed to provide x-ray transmission data along a number of ray paths through a body undergoing examination. X-ray energy from each source in the array is collimated to illuminate only a small sector of the detector array. High speed, unambiguous x-ray transmission information, is thereby produced.

High speed computerized tomography imaging system

An electronic current transducer for high voltage transmission lines including a fast analog data channel for providing effective relaying information which is stablized by a slow, highly accurate, channel which is insensitive to changes in gain. In addition for dc transmission lines where polarity may reverse, offsetting or biasing allows for bipolar measurement.

Electronic current transducer for high voltage transmission lines

A device for the electrostatic recording of x-ray images comprises two spaced electrodes with a gas-filled gap therebetween. One of the electrodes comprises a layer of an ultraviolet emitting fluorescent material and a layer of an air-exposable ultraviolet-sensitive photoemitting material. A plastic sheet is adjacent to the other electrode. An electric field is applied across the gap to accelerate photoelectrons emitted by the photoemitting material. The electrostatic image formed on the plastic sheet is developed xerographically after the exposure.

Photoemissive cathode and method of using comprising either

An improved ionization chamber type x-ray detector comprises a heavy gas at high pressure disposed between an anode and a cathode. An open grid structure is disposed adjacent the anode and is maintained at a voltage intermediate between the cathode and anode potentials. The electric field which is produced by positive ions drifting toward the cathode is thus shielded from the anode. Current measuring circuits connected to the anode are, therefore, responsive only to electron current flow within the chamber and the recovery time of the chamber is shortened. The grid structure also serves to shield the anode from electrical currents which might otherwise be induced by mechanical vibrations in the ionization chamber structure.

Gridded ionization chamber

A two-dimensional array of ionization chamber x-ray detector cells comprises a plurality of planar anode assemblies disposed equi-distant between parallel cathode plates in a gas of high atomic number. Each anode assembly comprises a plurality of conductive strips disposed on a thin dielectric sheet in a direction substantially parallel to the incident x-ray energy.

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Schenectady, NY, United States of America

John M Houston