Abstract: In an image converter tube, the brightness contrast of the output picture is reduced by light which is internally reflected at the surfaces of the window through which the image is viewed. The contrast can be improved by making the window partially light-absorbing, at the expense of a reduction in the overall optical gain. This gain varies considerably from tube to tube. By adding an external filter on the output window, the transmission of the filter can be chosen for each tube to provide the minimum acceptable gain and thus the maximum obtainable contrast.

Abstract: A nebulizer for use with spectroscopy having a main body member containing, within a guide bore, a venturi body, a liquid feed tube and a sleeve surrounding the tube and having air passages formed therein. The venturi body contains an axial throat which communicates directly with a relatively large chamber--e.g., at least four times the diameter of the throat--and that throat is held coaxial with the guide bore by radial confinement of the venturi body within that bore. The tube extends into the throat towards the chamber and terminates adjacent the outlet end of the throat. The sleeve fits within the guide bore and over the tube to hold the tube concentric with the throat and the outside diameter of the tube is approximately 75% of the throat diameter to provide clearance for passage of air. The air passages in the sleeve communicate with the inlet end of the throat through a space provided between respective frusto-conical end surfaces of the sleeve and venturi body.

Abstract: A gun for a linear-beam electron tube has a control grid for modulating the beam current which consists of an array of conductive web elements whose spacing from each other is much larger than their spacing from the concave emissive surface of the cathode. It was found that when this condition is met the grid can be operated at cathode potential while beam current is being drawn without distorting the electric accelerating field enough to ruin the focusing of the beam. Thus, when the grid is used to pulse the beam current on and off, it can have zero bias in the "on" condition, whereby the pulse modulator can be greatly simplified.

Abstract: An all-metal joint is provided wherein a metal gasket disposed between mating flanges can readily be removed when the joint is disassembled. Opposing faces of the mating flanges are configured to provide a recess between the flanges in which a soft metal gasket of annular configuration can be received when the flanges are coupled together. Symmetrically disposed ridges on the opposing flange faces penetrate into a peripheral region of the gasket, thereby causing a portion of the gasket material to flow into an annular groove that forms the periphery of the recess between the opposing flange faces. This compressed material in the annular groove provides a gas-tight seal between the mating flanges. The configuration of the opposing flange faces is such that when the joint is dissassembled, the net force tending to retain the gasket in position against either one of the flange faces is minimized.

Abstract: In an electron gun having a control grid in contact with the face of the cathode, unwanted thermionic emission from the cathode can be effectively suppressed by applying a thin (1 micron) coating of boron nitride to the surface of the control grid. The boron nitride has low thermionic emission itself and, in addition, has an unusual ability to shed or eliminate any deposits of emissive material such as barium or its oxides which come in contact with the boron nitride layer. For optimum performance and longest lifetime, the boron nitride layer is applied over a pyrolytic graphite layer which may be the conductive grid itself.

Abstract: A pulse damper for use in high-pressure liquid pumping applications such as liquid chromatography comprises a length of flattened polytetrafluoroethylene tubing that can be coupled to the high-pressure liquid flow line. The flattened tubing is enclosed within a liquid-tight housing structure completely filled with a compressible liquid, and the end of the tubing are coupled to the high-pressure flow line by fittings mounted inside the housing structure. When a transient pressure variation occurs in the flow line, the cross-section of the tubing changes from a flattened elliptical configuration to a more rounded configuration as the pressure pulse temporarily overcomes the stresses that tend to maintain the tubing in its flattened configuration. The restoring force of the compressible liquid in the housing structure surrounding the tubing prevents expansion of the tubing beyond a desired limit during a pulse, so that the tubing cannot burst when its cross-sectional configuration changes.

Abstract: Secondary electrons emitted from an electron-collecting electrode of a vacuum tube degrade the performance. Emission of high-speed secondaries is reduced by coating the electron-collecting surface with a material of low atomic number. Emission of low-speed secondaries is a less predictable function of the surface material and structure. The invention comprises a coating of aluminum boride or similar substance, which has low secondary emission and is also easy to outgas.

Abstract: A gun for a linear-beam electron tube has a control grid for modulating the beam current which consists of an array of conductive web elements whose spacing from each other is much larger than their spacing from the concave emissive surface of the cathode. It was found that when this condition is met the grid can be operated at cathode potential while beam current is being drawn without distorting the electric accelerating field enough to ruin the focusing of the beam. Thus, when the grid is used to pulse the beam current on and off, it can have zero bias in the "on" condition, whereby the pulse modulator can be greatly simplified.

Abstract: A high power gyro device includes a source of electrons. The electrons from this source are formed into a beam in which individual electrons are made to follow helical paths by a DC magnetic field. The angular velocity of the beam electrons is modulated as the beam passes through an oscillating electric field in a resonant cavity or waveguide so that a high power electromagnetic wave is established in the region as a result of an interaction between the beam and field. A collector for the beam is positioned on the axis, while an output waveguide for the wave is positioned at right angles to the axis. Upstream of the collector, the wave is reflected to the output waveguide by a reflecting surface having an aperture for passing the electron beam to the collector.