Abstract: Electrostatic x-ray imaging apparatus of the type having a gas-filled chamber bounded by a photocathode and a charge-receiving sheet anode has a control mesh positioned in the gas-filled gap and maintained at a positive voltage with respect to the cathode to facilitate high avalanche amplification and has a voltage between the mesh member and the anode chosen in the plateau region of the x-ray photocurrent versus voltage curve, to achieve a nearly constant efficiency of charge collection at the anode, independent of accumulation of charge thereat.

Abstract: Apparatus for X-ray radiography includes a conductive cathode, receiving X-radiation differentially attenuated by passage through an object to be studied, and a conductive anode spaced from the cathode and bearing a sheet of insulative material upon which a charge image of the object is to be formed; and a structured photocathode extending from the cathode towards the anode. The photocathode, formed of cesium iodide and the like, is of relative great thickness and surface area to have large X-ray quantum absorption and photoelectron emission, whereby a lower exposure dosage of X-radiation is required for a radiographic exposure. A plurality of different photocathode structures are disclosed.

Abstract: Apparatus for X-ray radiography includes a conductive cathode, receiving X-radiation differentially attenuated by passage through an object to be studied, and a conductive anode spaced from the cathode and bearing a sheet of insulative material upon which a charge image of the object is to be formed; and a structured photocathode extending from the cathode towards the anode. The photocathode, formed of cesium iodide and the like, is of relative great thickness and surface area to have large X-ray quantum absorption and photoelectron emission, whereby a lower exposure dosage of X-radiation is required for a radiographic exposure. A plurality of different photocathode structures are disclosed.

Abstract: Apparatus for X-ray radiography includes a conductive cathode, receiving X-radiation differentially attenuated by passage through an object to be studied, and a conductive anode spaced from the cathode and bearing a sheet of insulative material upon which a charge image of the object is to be formed; and a structured photocathode extending from the cathode towards the anode. The photocathode, formed of cesium iodide and the like, is of relative great thickness and surface area to have large X-ray quantum absorption and photoelectron emission, whereby a lower exposure dosage of X-radiation is required for a radiographic exposure. A plurality of different photocathode structures are disclosed.

Abstract: A tunable laser system emitting coherent radiation selectively variable over the range of wavelengths from about 2760 A to about 3220 A utilizes a crystal, composed of fluoride of at least a Column IIIb metal doped with trivalent ions of cerium and pumped with high average power pulses. The crystal is emplaced in an optical cavity having means such as diffraction grating, etalon, or optically-tunable prism, to vary the coherent emission wavelength.

Abstract: Photocontrolled ion-flow electron radiography apparatus has a multi-layered mesh structure, comprised of a conductive apertured sheet supporting an insulating layer, overlayed with a conductive screen and a top-most layer of photoconductive material, to control an ion stream responsive to a charge image formed in the photoconductive layer responsive to a pattern of x-rays differentially-absorbed by an object to be analyzed.

Abstract: Apparatus for X-ray radiography includes a conductive cathode, receiving X-radiation differentially attenuated by passage through an object to be studied, and a conductive anode spaced from the cathode and bearing a sheet of insulative material upon which a charge image of the object is to be formed; and a structured photocathode extending from the cathode towards the anode. The photocathode, formed of cesium iodide and the like, is of relative great thickness and surface area to have large X-ray quantum absorption and photoelectron emission, whereby a lower exposure dosage of X-radiation is required for a radiographic exposure. A plurality of different photocathode structures are disclosed.

Abstract: An improved direct charge readout electron radiography apparatus of the type having an upper electrode receiving differentially-absorbed X-radiation, a lower electrode including a plurality of parallel transparent, conductive strips overlaid with a layer of photoconductive material; and means for scanning a beam of light through the transparent strips and into the overlying photoconductive material layer for selectively transferring charge patterns induced therein responsive to the pattern of differentially-absorbed X-radiation, utilizes at least one lead means strip, positioned substantially transverse to, and spaced from the ends of, the plurality of conductive strips. The transverse lead means strip is connected to sequential ones of the parallel strips responsive to illumination of the photoconductive material in the area between the transverse strip and an adjacent end of each sequential parallel strip.

Abstract: A tunable laser system emitting coherent radiation selectively variable over the range of wavelengths from about 1650 A to about 3300 A utilizes a crystal, composed of a fluoride of at least a Column IIIb metal doped with at least one trivalent ion of a lanthanide series element, and pumped with high average power pulses. The crystal is emplaced in an optical cavity having means, such as a diffraction grating, etalon, or optically-tunable prism, to vary the coherent emission wavelength.

Abstract: A method and apparatus for photocontrolled ion-flow electron radiography utilizes a selectably movable phosphor plaque for controlling the selective discharge of a precharged photoconductive layer responsive to differential x-ray absorption in an object to be analyzed, to generate a charge image differentially controlling the deposition of ions upon a film for xerographic recording.

Abstract: An electrostatic X-ray image recording device having a pair of spaced electrodes with a gas-filled gap therebetween, and including discrimination means, having a conductive mesh supporting a photocathodic material, positioned in the gas-filled gap between a first electrode having a layer of ultraviolet-emitting fluorescent material and a second electrode having a plastic sheet adjacent thereto for receiving photoelectrons emitted by the photocathodic material and accelerated to the second electrode by an applied field. The photoconductor-mesh element discriminates against fast electrons, produced by direct impingement of X-rays upon the photocathode to substantially reduce secondary electron production and amplification, thereby increasing both the signal-to-noise and contrast ratios. The electrostatic image formed on the plastic sheet is developed by zerographic techniques after exposure.