The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Research is continuing to improve the performance of a 2 MW CW RF load for gyrotrons and electron cyclotron heating systems. Efforts are focused on reducing reflected power and cost. The load is designed to dissipate more than 2 MW CW of RF power, and recent tests demonstrated the power capability exceeds 1.7 MW.
Calabazas Creek Research, Inc. is developing a compact, inexpensive broadband system that replaces the external matching optical unit for coupling RF power from MW-class gyrotrons into transmission lines. A critical component is a Brewster window in HE11 waveguide. This paper describes progress in fabricating and testing critical components.
Calabazas Creek Research, Inc. and the University of Maryland are developing high quantum efficiency (QE) reservoir cathodes for accelerators, free-electron lasers, ultra-fast electron microscopes and other applications. High QE materials are deposited on an emitter sealing a reservoir of cesium chromate. An integral heater provides a continuous flow of cesium to replace that lost by evaporation,...
Calabazas Creek Research, Inc. is developing a broadband system to couple RF power from MW-class gyrotrons that eliminates the external matching optical unit. A critical component is a Brewster window in HE11 waveguide. This paper describes progress in fabricating and testing of the window.
A new, 1.5 MW RF load for gyrotrons is presented. The design actively distributes the RF power within the load to avoid constructive interference issues that cause arcing and excessive heating. A bellows replaces rotating seals used in previous loads, increasing reliability and reducing cost. The design meets specifications for the ITER ECH system.
In this letter, we propose sub-terahertz (sub-THz) slow-wave circuits for coherent radiation sources through beam-wave interaction mechanism. The circuits are prepared using microfabrication in advanced silicon (Si) technologies. Our approach is to split the circuit into multi levels allowing a low aspect ratio configuration and alleviating the loading effect of deep-reactive-ion etching on silicon...
Many electron guns with thermionic emission must take into account the effects of the spread in the particle velocities emitted from the cathode. Via Liouville's theorem, this distribution function is a constant of the particle motion. Therefore, if proper distribution of particle positions and velocities at the emitter can be prescribed then accurate nonlaminar, space-charge flows throughout the...
Calabazas Creek Research, Inc. (CCR), in collaboration with the University of Maryland, is developing robust, long-life, high quantum efficiency (QE) photocathodes for accelerator and light source applications. The program includes development of production facilities for photocathode fabrication and transport.
Calabazas Creek Research, Inc. is developing a broadband system to couple RF power from MW-class gyrotrons that eliminates the external matching optical unit. A critical component is a Brewster window in HE11 waveguide. This paper describes progress in fabrication and testing of the window.
Calabazas Creek Research is developing several, high power, periodic permanent magnet (PPM) focused klystrons. PPM focusing offers reduced power consumption and low weight. We report on the design and testing of an S-band, pulsed klystron capable of providing 5 MW power for advanced medical and industrial accelerators, and on the design of the gun and magnetic structure for a PPM-focused, multiple...
Most all high power RF sources and components require liquid cooling, usually high purity water. Copper and associated braze alloys are susceptible to corrosion if the water contains impurities or modest levels of oxygen. Unfortunately, high purity water is not readily available in many locations, including developing countries, remote sites, and naval vessels. The U.S. Navy is funding development...
A C-Band, multiple beam klystron was designed, fabricated, prepared for high voltage testing. The klystron employs controlled porosity reservoir cathodes operating at 30 A/cm2 to generate 18 beams. The RF circuit consists of eight buncher cavities and an extended interaction output cavity. The challenge was achieving the required 6.6% bandwidth. The gun includes a grid for fast pulse operation. The...
Electron guns for RF sources typically use barium dispenser cathodes to produce electron emission. Barium diffuses to the emission surface whenever the cathode is hot to replace that lost by evaporation. The barium forms barium oxide to reduce the surface work function. Barium that evaporates from the surface is deposited on nearby surfaces, including grids and high voltage electrodes. The barium...
Calabazas Creek Research, Inc., in collaboration with Fermilab and Communications & Power Industries, LLC. (CPI), is developing a phase locked, 100 kW peak, 10 kW average magnetron-based RF system for driving accelerators. Phase locking will be achieved using an approach originating at Fermilab [1] that includes control of both amplitude and phase on a fast time scale.
This paper will present a more efficient and accurate method to simulate thermal-velocity effects. It inverts the cumulative density function of the Maxwell-Boltzmann distribution to determine the thermal velocities of the launch particles from the emitter. It requires fewer launch particles and still satisfies the required statistics.
RF loads are required to test high power gyrotrons currently in development for the ITER fusion test reactor in France. Because ITER is a nuclear facility, strict safety and environmental specifications are applied to all equipment installed in the facility. This requires RF loads that can dissipate 1.5 MW CW at 170 GHz with strict limitations on materials in contact with vacuum and cooling systems...
High quantum efficiency, long-life photocathodes are required for the next generation of accelerators, light sources, and ultra-fast electron microscopes. This requirement is being addressed by depositing high QE materials on Controlled Porosity Reservoir (CPR) cathodes. A production facility is now on line to produce CPR photocathodes, including development of equipment and interface mechanisms for...
Calabazas Creek Research, Inc. is developing a broadband system to couple RF power from MW-class gyrotrons that eliminates the external matching optical unit. A critical component is a Brewster window in HE11 waveguide. This paper describes progress in fabricating and testing the window and the associated hardware.
Calabazas Creek Research, Inc. and the University of Maryland are developing high quantum efficiency (QE) reservoir cathodes for accelerators, free-electron lasers, ultra-fast electron microscopes and other applications. High QE materials are deposited on an emitter allowing diffusion of cesium from a reservoir. An integral heater provides a continuous flow of cesium to replace that lost by evaporation,...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.