| Paper | Title | Other Keywords | Page |
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| MOPMW044 | Design of an RF Device to Study the Multipactor Phenomenon | cavity, simulation, electron, experiment | 507 |
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| Multipacting is a parasitic electron avalanche process that may occur in RF devices such as cavities or couplers. As it can be detrimental to the operation of these devices, the accelerator group at LPSC is currently designing a coaxial resonant cavity in order to study this phenomenon. In order to determine the measurable parameters on the cavity, calculations were performed and validated with numerical simulations. In a second time multipacting simulations were conducted to determine if the experiment will allow to observe multipacting. | |||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW044 | ||
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| MOPOR026 | Measurement of the Energy Distribution Function of Electrons Generated by Radio-frequency Induced Multipacting in a Beam Pipe | electron, gun, radio-frequency, diagnostics | 664 |
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| The development of Electron Multipacting (EM) in high intensity particle accelerators depends, amongst others, on the Secondary Electron Yield (SEY) of surfaces facing the beam. In-situ studies of electron clouds in particle accelerators must cope with operation schedule and other technical constrains. To overcome these difficulties, CERN implemented a Multipactor test bench, where EM is generated by Radio-Frequency (RF), using the beam pipes as a coaxial resonators. This tool was already successfully used to assess the effectiveness of low SEY carbon coatings on dipoles of the SPS at CERN and to study the conditioning dynamics of beam pipes. In this paper we present the development of an in-house built Retarding Field Energy Analyser (RFEA) to measure the Electrons Energy Distribution Function (EEDF) in the Multipactor test bench. The design of the electrodes was based on simulations in order to optimize sensitivity and energy resolution. The setup was tested with an electron gun at different energies before insertion in the Multipactor test bench. The evolution of the EEDF is measured at different RF powers. Feasibility to perform measurements in the machine is discussed. | |||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR026 | ||
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| WEPMB018 | Multipactor Simulations in 650 MHz Superconducting Spoke Cavity for an Electron Accelerator | cavity, electron, simulation, laser | 2161 |
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Funding: The work is supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan. In order to realize a compact industrial-use X-ray source based on the laser-Compton scattering, a superconducting spoke cavity for an electron accelerator operated at 4K is under development. While the initially proposed operating frequency was 325MHz considering the 4K operation, we decided to start from the half scale model at 650MHz to accumulate our production experience of spoke cavity within our limited resources. In the present contribution, procedures and results of multipactor simulations for 650MHz spoke cavities are briefly introduced. |
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| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB018 | ||
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| WEPMB047 | Higher Order Modes Couplers for 800 MHz Harmonic Cavity | HOM, cavity, damping, electron | 2217 |
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Funding: *Work supported by Ministry of Education and Science grant 3.245.2014/r For the higher order modes damping (HOM) in the 800 MHz superconducting single cell cavity the HOM coupler was developed. Several versions of the coupler design were shown. For the chain of two cavities with couplers the calculations of external Q-factor are presented. The calculations of multipactor discharge of cavity were also conducted. Higher order modes, Tesla, couplers |
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| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB047 | ||
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| THPMW040 | Multipactor Discharge in a Resonator as an Active Switch for RF Pulse Compression | cavity, plasma, electron, klystron | 3640 |
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Funding: Phase I DOE SBIR Pulse compression is a method of increasing the peak power of the microwave pulse at the expense of its length. Over the years a number of pulse compressors had been demonstrated with some being bulky but efficient, like the binary pulse compressor and other being compact but less efficient, like SLED-II. An active pulse compressor had been proposed to increase the efficiency and compression ratio which relies on a high power active switch. Currently there are no practical switches that can work reliably with 100 s of megawatts of power. Most of the switches (ferroelectric, plasma-based, semiconductor) are limited by the breakdown strength of various dielectric inserts. In this paper we report on an active switch development which is based on a pure copper resonator and controlled by a single-side multipactor discharge at a metallic wall in the presence of a resonant DC magnetic field and a normal to metal rf field. The discharge is ignited by external rf power produced by inexpensive 2.45 GHz, 1-5 kW magnetrons. |
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| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW040 | ||
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