Abstract: Electron gun. The electron gun includes a circular cathode. The circular cathode comprises a spherical surface. The electron gun further includes a focus electrode. The focus electrode has four quadrants. The focus electrode is disposed about the circular cathode. The focus electrode includes four primary focus angle points. At least two of the four, adjacent, primary focus angle points have different angle values. Each of the four primary focus angle points is in a different quadrant. Focus angles on the focus electrode between any two primary focus angle points vary from one primary focus angle point to another primary focus angle point.

Abstract: The invention relates to a cathode arrangement comprising: a cathode body housing an emission surface for emitting electrons in a longitudinal direction, wherein the emission surface is bounded by an emission perimeter; a focusing electrode at least partially enclosing the cathode body in a transversal direction and comprising an electron transmission aperture for focusing the electrons emitted by the emission surface, wherein the aperture is bounded by an aperture perimeter, wherein the cathode body is moveably arranged within the focusing electrode over a maximum transversal distance from an aligned position, and wherein the aperture perimeter transversally extends over the emission surface and beyond the emission perimeter over an overlap distance that exceeds the maximum transversal distance.

Abstract: A klystron has a hollow beam electron gun that has a circular planar electron emitting surface. A hollow electron beam is directed from the electron gun through a plurality of drift tubes, resonant chambers and magnetic fields to a collector. The hollow electron beam does not experience significant radial movement and can operate at a lower beam voltage which reduces the required length of the RF interaction circuit and lowers the risks of RF arcing.

Abstract: A cathode ray tube has an electron beam generating section including an indirectly heated cathode structure and first and second electrodes arranged in the order named. The cathode structure is composed of a cathode sleeve for housing a heater therein, a cathode base metal disposed at an end of the cathode sleeve facing toward the first electrode, and an electron emissive oxide layer disposed on the cathode base metal. The electron emissive oxide layer is formed with a depression on a surface thereof facing the electron beam transmissive aperture in the first electrode. A maximum diameter of the depression is smaller than a maximum diameter of the electron beam transmissive aperture in the first electrode, and a maximum depth of the depression is smaller than the maximum diameter of the depression.

Abstract: Electron gun with band-shaped beams that includes a vacuum chamber extend in a longitudinal direction, a beam window running in the longitudinal direction along the vacuum chamber, and a cathode control-electrode system positioned within the vacuum chamber in the longitudinal direction. The cathode control-electrode system includes at least one substantially straight cathode positioned substantially parallel to a longitudinal axis of the cathode control-electrode system and the at least one substantially straight cathode has bulges formed at defined distances. The bulges are shaped to produce a substantially homogeneous current density distribution along the at least one substantially straight cathode and support units are located in the cathode control-electrode system to correspond with the bulges. The bulges are removably couplable to the support units.

Abstract: A mechanically tunable magnetron injection gun (MIG) provides an annular, relativistic beam of electrons for injection into an axially aligned magnetic field of a gyrotron-class device. The electron emitter encircles a center electrode. Turning a knob adjusts the center electrode's axial position relative to the rest of the cathode. The adjustable center electrode provides an effective means for local field adjustment. The center electrode is located in a particularly sensitive electric field region and adjusts the electric field so as to tune the electron beam from the inside out. Adjusting the center electrode position while the device is in operation is a means for providing mechanical tunability (with respect to beam quality and transverse-to-axial velocity ratio) for the MIG.

Abstract: An electron gun for producing a beam of electrons has an elongated, linear thermionic cathode and a focusing electrode. The opposite ends of the cathode are engaged by adjustable holders which enable the spatial separation between the cathode and focusing electrode to be easily varied. The focusing electrode is electrically isolated from the cathode whereby fine tuning of the electron beam may be accomplished by varying the potential difference between the focusing electrode and cathode.

Abstract: In electron guns for electronic tubes, such as travelling wave tubes, for power modulating the electron beam, the distance between the cathode and the modulation grid increases the closer to the axis of the tube. Such a gun can be applied to travelling wave tubes operating with a zero enabling voltage and whose modulating frequency covers a very wide band.

Abstract: An electron gun for a high power klystron which includes a cathode which emits electrons; a focus electrode which, connected to the cathode through a supporting member composed of a material of high electric resistivity, makes the electrons emitted from the cathode produce an electron beam; and an anode which accelerates the electron beam produced by the focus electrode. The supporting member composed of a material of high electric resistivity may alternately be provided between the first and the second portions of the focus electrode, or between the cathode and the second focus electrode portion, wherein the two focus electrode portions are arranged adjacently to each other in the axial direction of the device, and wherein the first focus electrode portion is directly connected to the cathode.

Abstract: An improved dual-mode electron gun includes a close-in and a further control grid to control the laminar flow of electrons which pass from the smooth spherical surface of a cathode toward an annular anode. In the high mode of operation, the close-in grid is maintained, for example, at +36 volts while the further grid is maintained at +250 volts. During the low mode of operation, the close-in grid is maintained at -36 volts while the further grid potential is +250 volts. The two control grids are divided into inner circular and an outer annular areas. The close-in grid has more conductive elements in its outer annular area than in the same area of the further grid. The two grids are then aligned so that the close-in grid functions as a control grid to block the flow of electrons from the outer annular area during the low mode of operation and as a shadow grid for the further control grid during both low and high modes of operation.

Abstract: An improved electron gun is shown with a cathode having a smooth, concaved surface and a grooved pattern therein which matches, and is aligned with, the pattern of a shadow grid placed immediately before the cathode surface so that the outer, larger radius of curvature of the shadow grid closest to the cathode is substantially identical and concentric with the radius of curvature of the smooth, concave cathode surface. Beyond the shadow grid is a control grid which controls the flow of electrons emitted from the cathode toward an anode. The grooves which form the pattern within the cathode surface have tapered side walls and rounded outer and inner corners to improve the flow of emitted electrons and facilitate manufacture.

Abstract: The purpose of the off-axis electron gun is to generate a beam of electrons and to deflect the beam onto the axis of a device which utilizes the beam. The off-axis electron gun includes an arcuate wire electron emitting source subtending an azimuthal angle of up to 125.degree., a non-intercepting azimuthally asymmetric focussing and deflecting electrode located at and around the electron source, and an anode plate with a beam exit hole. The non-intercepting electrode has an arcuate slot subtending a predetermined angle at a predetermined radius from the beam axis in which the arcuate wire electron source is mounted in electrical isolation from the electrode. The deflecting section of the electrode is azimuthally asymmetric in shape such that when selected voltages are applied between the wire source, the focussing and deflecting sections of the non-intercepting electrode and the anode, an electric field is produced which directs the electrons towards the axis, focusses the beam and deflects it onto the axis.

Abstract: A magnetron injection gun comprising a conical cold-cathode and a cylindrical anode coaxially surrounding the cold-cathode. The anode is provided with an annular projection extending toward the emission ring surface, and the surface of the conical cold-cathode is coated with an insulating film, except for a portion opposite the end of the annular projection, which forms a conductive emission ring.

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 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: In an electron gun of a cathode ray tube of the type comprising a cathode electrode for emitting an electron beam, a first grid electrode for focusing the electron beam and a second grid electrode for accelerating the electron beam, the cathode surface which emits the electron beam is a concaved surface which creates different electron beam focusing effects in two orthogonal directions and the first grid electrode comprises a flat plate having an elongated iris opening with its major axis coincided with the direction of the cathode surface in which the focusing effect is strong and the minor axis coincided with the direction of the cathode surface in which the focusing effect is weak.

Abstract: A linear beam tube is provided with a gridded electron gun in which a concave cathode surface is provided with concave channels from which electrons are emitted. The channels may be arranged as concentric annuli. In a preferred embodiment the channels extend radially outwards from the center of the cathode to minimize the effects of temperature distortion. The cathode is provided with a shadow grid and a control grid is spaced from and aligned therewith.