Abstract: An inductive output tube (IOT) provides improved efficiency and larger bandwidth. In one embodiment, an IOT is provided with an electron gun that generates an electron beam, a tube body, a collector for collecting the electron beam, and an extended-interaction output circuit. The electron beam travels through the tube body and the extended-interaction output circuit. The extended-interaction output circuit is located within the tube body. The extended-interaction output circuit comprises a short-circuited resonant structure. The extended-interaction output circuit is used for reducing undesired components of a radio frequency (RF) wave, increasing desired components of the RF wave, and slowing down the propagation of the RF wave. (That is the circuit increases the integral of the electric field along the path of the beam electrons while decreasing the stored energy associated with those fields.) The extended-interaction output circuit also provides the IOT with larger bandwidth operation.

Abstract: A high-current, high-gradient, high-efficiency, multi-stage cavity cyclotron resonance accelerator (MCCRA) provides energy gains of over 50 MeV/stage, at an acceleration gradient that exceeds 20 MeV/m, in room temperature cavities. The multi-stage cavity cyclotron resonance accelerator includes a charged particle source, a plurality of end-to-end rotating mode room-temperature cavities, and a solenoid coil. The solenoid coil encompasses the cavities and provides a substantially uniform magnetic field that threads through the cavities. Specifically, the MCCRA is provided with a constant magnetic field sufficient to produce a cyclotron frequency a little higher than the RF of the accelerating electric field. A plurality of input feeds, each of which respectively coupled to a cavity, are also provided. According to an embodiment of the invention, the beam from the first cavity passes through a cutoff drift tube and is accelerated further with a cavity supporting a still lower radio-frequency electric field.

Abstract: An inductive output tube (IOT) provides improved efficiency and larger bandwidth. In one embodiment, an IOT is provided with an electron gun that generates an electron beam, a tube body, a collector for collecting the electron beam, and an extended-interaction output circuit. The electron beam travels through the tube body and the extended-interaction output circuit. The extended-interaction output circuit is located within the tube body. The extended-interaction output circuit comprises a short- circuited resonant structure. The extended-interaction output circuit is used for reducing undesired components of a radio frequency (RF) wave, increasing desired components of the RF wave, and slowing down the propagation of the RF wave. (That is the circuit increases the integral of the electric field along the path of the beam electrons while decreasing the stored energy associated with those fields.) The extended-interaction output circuit also provides the IOT with larger bandwidth operation.

Abstract: An inductive output tube (IOT) of a multi-staged depressed collector provides improved efficiency by approximating a Brillouin electron beam flow. In one embodiment, an IOT is provided with an electron gun that generates an electron beam, a tube body, a multi-staged depressed collector for collecting the electron beam, and a magnetic solenoid. The electron beam travels through the tube body. The magnetic solenoid produces a magnetic flux that focuses the electron beam as it travels through the tube body. The magnetic flux includes a portion that threads through the electron gun. The IOT is adapted to reduce this portion of the magnetic flux in order to provide improvements in the efficiency of the IOT.

Abstract: A high-current, high-gradient, high-efficiency, multi-stage cavity cyclotron resonance accelerator (MCCRA) provides energy gains of over 50 MeV/stage, at an acceleration gradient that exceeds 20 MeV/m, in room temperature cavities. The multi-stage cavity cyclotron resonance accelerator includes a charged particle source, a plurality of end-to-end rotating mode room-temperature cavities, and a solenoid coil. The solenoid coil encompasses the cavities and provides a substantially uniform magnetic field that threads through the cavities. Specifically, the MCCRA is provided with a constant magnetic field sufficient to produce a cyclotron frequency a little higher than the RF of the accelerating electric field. A plurality of input feeds, each of which respectively coupled to a cavity, are also provided. According to an embodiment of the invention, the beam from the first cavity passes through a cutoff drift tube and is accelerated further with a cavity supporting a still lower radio-frequency electric field.

Abstract: An inductive output tube (IOT) of a multi-staged depressed collector provides improved efficiency by approximating a Brillouin electron beam flow. In one embodiment, an IOT is provided with an electron gun that generates an electron beam, a tube body, a multi-staged depressed collector for collecting the electron beam, and a magnetic solenoid. The electron beam travels through the tube body. The magnetic solenoid produces a magnetic flux that focuses the electron beam as it travels through the tube body. The magnetic flux includes a portion that threads through the electron gun. The IOT is adapted to reduce this portion of the magnetic flux in order to provide improvements in the efficiency of the IOT.

Abstract: A linear beam device comprises a cathode and an anode spaced therefrom, with the anode and cathode being operable to form and accelerate an electron beam. An RF interaction region having a drift tube is arranged relative to the anode to permit the electron beam to pass therethrough. A multi-stage depressed collector of the linear beam device has a plurality of collector electrodes successively arranged to collect spent electrons of the electron beam after passing through the RF interaction region. Each one of the plurality of collector electrodes has a distinct voltage level applied thereto defining a decelerating electric field within the collector. At least one of the plurality of collector electrodes further comprises a collecting surface having a shape that is normal to a coincident trajectory of the spent electrons, whereby a substantial portion of the collecting surface is covered with a plurality of narrow grooves.

Abstract: An electron emissive cathode is designed based upon the triple-junction effect. The electron emitting cathode comprises a cathode body having an emitting surface for emitting electrons. A ferroelectric material is impregnated within the cathode body such that the ferroelectric material enhances the emission of electrons from the emitting surface. The cathode body may comprise a tungsten matrix material and the ferroelectric material may comprise a barium titanate, lithium niobate material and/or other known ferroelectrics.

Abstract: A linear amplifier comprises an electron gun assembly having a cathode, and an anode spaced from the cathode. A relatively high voltage potential is applied between the anode and the cathode, and the cathode provides an electron beam in response to the relatively high voltage potential. A control grid is spaced between the cathode and the anode, and is coupled to an input port adapted to receive the input signal. The input signal causes the control grid to density modulate the beam. The control grid is also coupled to a bias voltage source to preclude transmission of the electron beam during the negative half cycle of the input signal. A plurality of collector stages are provided with a respective electric potential thereto ranging between a potential of the cathode and a potential of the anode to efficiently collect the electrons of the beam after passing the anode.

Abstract: A low-power wide-bandwidth klystron comprises a cathode having an electron emitting surface capable of emitting an electron beam and a collector spaced from said cathode and designed to collect the electron beam emitted from the cathode. An anode is disposed between the cathode and the collector in order to channel the electron beam into a series of drift tubes that define the electron beam path between the anode and the collector. The drift tubes define gaps in which the input cavity and output cavity interact with the electron beam. The input cavity velocity modulates the electron beam by way of a radio frequency input signal and the output cavity extracts the amplified radio frequency signal from the electron beam. The drift tubes may define additional gaps between the input cavity and output cavity for intermediate cavities that would provide additional amplification.

Abstract: A linear beam device having a multi-stage depressed collector is provided with a single crowbar circuit that quickly removes all voltages from the collector electrodes upon detection of an arc between the collector electrodes. The linear beam device comprises a cathode and an anode spaced therefrom that are operable to form and accelerate an electron beam. A collector having a plurality of successive collector electrodes is arranged downstream from the anode to collect electrons of the electron beam. At least one power supply is coupled to the collector and provides a plurality of distinct voltage levels to respective ones of the collector electrodes. The power supply comprises a plurality of serially coupled filter capacitors, with each one of the filter capacitors being charged to a respective difference between adjacent ones of the distinct voltage levels. A crowbar circuit is coupled across the plurality of filter capacitors.

Abstract: A linear beam amplification device includes an axially centered electron emitting cathode and an anode spaced therefrom. The cathode provides an electron beam in response to a relatively high voltage potential defined between the cathode and the anode. A control grid is spaced between the cathode and anode for modulating the electron beam in accordance with an input signal. A signal input assembly of the linear beam amplification device comprises an axial input cavity into which the input signal is inductively coupled. The grid-cathode region is electrically connected to the input cavity. A low impedance grid-anode cavity is disposed coaxially with the input cavity and is in electrical communication with an interaction region defined between the grid and the anode. The low impedance of the grid-anode cavity is provided by constructing the cavity of a material having a relatively high surface resistivity, such as iron.

Abstract: An electron gun provides multiple convergent beamlets in a rectilinear flow for use in multiple drift tubes of a multiple beam klystron. The electron gun comprises a cathode having a concave emitting surface and an anode having a concave surface defined by respective ends of a plurality of hollow drift tubes. The anode surface is spaced from the cathode surface and has a positive voltage potential applied thereto to define a series of equipotential contour surfaces between the cathode and the anode. A plurality of grids are located between the cathode and the anode, with each one of the grids being disposed coincident with a respective one of the equipotential contour surfaces with a first one of the grids located closely adjacent to the cathode surface. Each one of the grids further has a plurality of perforations extending therethrough in substantial registration with each other and with respective openings of the plurality of drift tubes.

Abstract: A focusing system for a helix TWT includes a polepiece structure for conducting magnetic flux to a drift tube of the TWT in a first general direction and conducting the magnetic flux from the drift tube in a second general direction perpendicular to the first general direction. Radially magnetized permanent magnets are disposed at outer portions of the polepiece structure and supply the magnetic flux. A first pair of the magnets have a first direction of polarity, and a second pair of the magnets have a second direction of polarity opposite to the first direction. An outer shell encapsulates the polepiece structure and the magnets, and provides a magnetic flux return path. An electron beam travels in the drift tube and the magnetic flux provides focusing for the electron beam.

Abstract: A high efficiency linear amplifier comprises an electron gun assembly having a cathode and an anode, the cathode being operable at a relatively high voltage potential relative to the anode to form and accelerate an electron beam. A control grid is disposed between the cathode and the anode, and is biased relative to the cathode for Class B operation. A high frequency input signal is applied to the control grid to density modulate the electron beam. A shadow grid may be disposed between the control grid and the cathode. A drift tube encloses the beam and includes a first portion and a second portion with a gap defined between the first and second portions. An inductive output cavity communicates with the gap, and the density modulated electron beam passed across the gap and induces an RF electromagnetic signal into the cavity. A multistage depressed collector accepts and dissipates the electrons of the beam which remain after transit across the gap.