| Paper | Title | Page |
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| WEPE066 | Beam Test of a High Pressure Cavity for a Muon Collider | 3494 |
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To demonstrate the feasibility of a high pressure RF cavity for use in the cooling channel of a muon collider, an experimental setup that utilizes 400-MeV Fermilab linac proton beam has been developed. In this paper, we describe the beam diagnostics and the collimator system for the experiment, and report the initial results of the beam commissioning. The transient response of the cavity to the beam is measured by the electric and magnetic pickup probes, and the beam-gas interaction is monitored by the optical diagnostic system composed of a spectrometer and two PMTs. |
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| WEPE069 | Study of Electron Swarm in High Pressure Hydrogen Gas Filled RF Cavities | 3503 |
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A high pressurizing hydrogen gas filled RF cavity has a great potential to apply for muon colliders. It generates high electric field gradients in strong magnetic fields with various conditions. As the remaining demonstration, it must work under high radiation conditions. A high intensity muon beam will generate a beam-induced electron swarm via the ionization process in the cavity. A large amount of RF power will be consumed into the swarm. We show the recent non-beam test and discuss the electron swarm dynamics which plays a key role to develop a high pressure RF cavity. |
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| THPEA046 | The MuCool Test Area and RF Program | 3780 |
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TThe MuCool RF Program focuses on the study of normal conducting RF structures operating in high magnetic field for applications in muon ionization cooling for Neutrino Factories and Muon Colliders. This paper will give an overview of the program, which will include a description of the test facility and its capabilities, the current test program, and the status of a cavity that can be rotated in the magnetic field which allows for a more detailed study of the maximum stable operating gradient vs. magnetic field strength and angle. |
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| THPEA047 | Dielectric Loaded RF Cavities for Muon Facilities | 3783 |
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Alternative RF cavity fabrication techniques for accelerator applications at low frequencies are needed to improve manufacturability, reliability and cost. RF cavities below 800 MHz are large, take a lot of transverse space, increase the cost of installation, are difficult to manufacture, require significant lead times, and are expensive. Novel RF cavities partially loaded with a ceramic for accelerator applications will allow smaller diameter cavities to be designed and built. The manufacturing techniques for partially loaded cavities will be explored. A new 200MHz cavity will be built for the Fermilab Proton Source to improve the longitudinal emittance and energy stability of the linac beam at injection to the Booster. A cavity designed for 400 MHz with a ceramic cylinder will be tested at low power at cryogenic temperatures to test the change in Qo due to the alumina ceramic. Techniques will be explored to determine if it is feasible to change the cavity frequency by replacing an annular ceramic insert without adversely effecting high power cavity performance. |
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| THPEA054 | Rectangular Box Cavity Tests in Magnetic Field for Muon Cooling | 3795 |
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Muon cooling requires high-gradient normal conducting cavities operating in multi-Tesla magnetic fields for muon beam focusing in an ionization cooling channel. Recent experience with an 805-MHz pillbox cavity at the Fermilab MuCool Test Area has shown significant drop in accelerating field performance for the case of parallel electric and magnetic fields. It has been suggested that having the magnetic field perpendicular to the electric field should provide magnetic insulation and suppress breakdown. An 805-MHz Cu rectangular box cavity was built for testing with the fields perpendicular. It was mounted on an adjustable support to vary the angle between the rf electric and external magnetic field. We report on design and operation of the rectangular box cavity. |
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| THPEB058 | Phase and Frequency Locked Magnetrons for SRF Sources | 4005 |
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Typically, high power sources for accelerator applications are multi-megawatt microwave tubes that may be combined together to form ultra-high-power localized power stations. The RF power is then distributed to multiple strings of cavities through high power waveguide systems which are problematic in terms of expense, efficiency, and reliability. Magnetrons are the lowest cost microwave source in dollars/kW, and they have the highest efficiency (typically greater than 85%). However, the frequency stability and phase stability of magnetrons are not adequate, when magnetrons are used as power sources for accelerators. Novel variable frequency cavity techniques have been developed which will be utilized to phase and frequency lock magnetrons, allowing their use for either individual cavities, or cavity strings. Ferrite or YIG (Yttrium Iron Garnet) materials will be attached in the regions of high magnetic field of radial-vaned, π−mode structures of a selected ordinary magnetron. A variable external magnetic field that is orthogonal to the magnetic RF field of the magnetron will surround the magnetron to vary the permeability of the ferrite or YIG material. |