Paper | Title | Other Keywords | Page |
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MOPO026 | The Resonance Frequency Shift After Applying the Cooling System for a Side Coupled Standing Wave Linac | cavity, controls, electron, coupling | 81 |
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A radio frequency accelerator tube used in linear medical accelerators includes three main sections of the radio frequency cavity, an electron gun and the X-ray target, which is vacuumed by a pump inside it. The electromagnetic energy loss in the structure of the cavity can increase the temperature of the tube, resulting in changes in the geometric dimensions and then changes in some of the cavity characteristics, such as the resonance frequency. A cooling system is required to prevent excessive change in the resonant frequency due to thermal loss. Also, it is necessary to perform some computer simulations to stabilize the cavity’s performance in the presence of electromagnetic energy thermal dissipation and the cooling system. In this paper, the simulation results of resonant frequency shifts after applying the cooling system have been reported. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO026 | ||
About • | paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019 | ||
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TUPO030 | Precise Evaluation of Characteristic of the Multi-layer Thin-film Superconductor Consisting of NbN and Insulator on Pure Nb Substrate | cavity, superconducting-RF, linac, SRF | 391 |
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In recent years, it has been pointed out that the maximum accelerating gradient of a superconducting RF cavity can be pushed up by coating the inner surface of the cavity with a multilayer thin-film structure that consists of alternating insulating and superconducting layers. In this structure, the principal parameter that limits the performance of the cavity is the critical magnetic field or effective Hc1 at which vortices start penetrating into the superconductor layer, and it is predicted to depend on the combination of the film thickness. We made samples that have NbN/SiO2 thin-film structure on pure Nb substrate with several thicknesses of NbN film deposited using DC magnetron sputtering method. Here, we report the measurement results of effective Hc1 of the NbN sample with a thickness of 200 nm by using the third-harmonic voltage method. In addition, we report the preliminary results to evaluate the dependence of the effective Hc1 on the thickness of the NbN film in the range 50 nm-200 nm. | |||
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Slides TUPO030 [0.305 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO030 | ||
About • | paper received ※ 18 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019 | ||
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TUPO054 | Fundamental Studies of Impurity Doping in 1.3 GHz and Higher Frequency SRF Cavities | cavity, niobium, SRF, electron | 458 |
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As the demand for more powerful, more efficient, and smaller superconducting RF accelerators continues to increase, both impurity doping and high-frequency cavities (> 1.3 GHz) have become hot topics for fundamental research because of their potential to significantly decrease surface losses and cost respectively. In this report, we present recent experimental and theoretical results on undoped and nitrogen-doped high-frequency cavities and on alternative doping agents in traditional 1.3 GHz cavities, with a focus on understanding the fundamental science of impurity doping. | |||
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Slides TUPO054 [1.956 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO054 | ||
About • | paper received ※ 16 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019 | ||
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TUPO059 | Latest Results of Salt Based Bipolar Electro-polishing R&D at Cornell | cavity, SRF, niobium, cathode | 473 |
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Acid free electropolishing would be safer to use and friendlier to the environment. A collaboration, sup-ported by the DOE SBIR Phase-II program, between Faraday Technology Inc. and Cornell University focused on salt-based bipolar electropolishing (BEP). In this paper, we present the latest salt-based BEP results. The superconducting performance of a single-cell 1.3GHz cavity has been carefully analyzed, showing that salt-based BEP is promising, but still has large room for improvement. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO059 | ||
About • | paper received ※ 19 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019 | ||
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THPO051 | The Multi-physics Analysis of LEAF RFQ | rfq, cavity, simulation, quadrupole | 805 |
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The 81.25 MHz CW RFQ is designed to accelerate heavy ions with Q/A from 1/7 to 1/2 at 0.5 MeV/u for the Low Energy Accelerator Facility (LEAF) at the Institute of Modern Physics (IMP) of the Chinese Academy of Science (CAS). The four-vane RFQ consists of six mod-ules with a total length of 5.95 meters, For the CW oper-ating mode, thermal management will be a very important issue, Therefore a multi-physics analysis is necessary to ensure that the cavity can stably operate at the high RF power . The multi-physics analysis process includes RF electromagnetic analysis, thermal analysis, mechanical analysis, and the frequency shift, the cooling water system is used for frequency tunning by the temperature adjustment, and also analyze RFQ undercuts, fixed tuners, and pi-mode rods, the results show that the thermal and structural design of this RFQ is reasonable. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO051 | ||
About • | paper received ※ 17 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019 | ||
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THPO053 | Status of the China Material Irradiation Facility RFQ | rfq, cavity, radiation, diagnostics | 811 |
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Funding: Supported by the National Magnetic Confinement Fusion Science Program of China (Grant No.2014GB104001) and the National Natural Science Foundation of China (Grant No.91426303). The pulsed high power test and beam test of the China Material Irradiation Facility RFQ have been implemented. Before this, the radio frequency measurements and tuning are performed. In this paper, the processes and results of the radio frequency measurements, tuning, pulsed high power test and beam test will be presented. The results of tests are in good agreement with the design. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO053 | ||
About • | paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019 | ||
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