| Paper | Title | Other Keywords | Page |
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| TUPMB010 | Magnetic Center Position and Tilt Angle of Quadrupole by Vibration Wire Method | quadrupole, experiment, radiation, alignment | 1127 |
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| Vibrating wire method and device are described to locate the magnetic center of a Quadrupole theoretically and experimentally. With rotating 180 degrees method, it is convenience to measure the position magnetic center from mechanical center. Tilt angle can also be measured because tilt of magnetic axis will cause the difference of measured magnetic center in different harmonic driving current frequency. Errors analysis shows that tilt of Quadrupole will cause the main error and improved device is described to adjust and measure the tilt angle to fix the errors caused by tilt. | |||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB010 | ||
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| TUPMB032 | Magnetic Field Characterisation of the First Series Dipole Magnet for the SIS100 Accelerator of FAIR | dipole, multipole, sextupole, ion | 1171 |
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| The procurement of the SIS100 dipoles was contracted without building and testing an appropriate model magnet. So the thorough test of the first of series magnet is the key issue for the final realisation of the complete series production. The core of these tests is the measurement and analysis of the magnetic field of the first dipole. We describe the adapted measurement technics next to a detailed analysis of the obtained field quality and point out the critical issues of the series production | |||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB032 | ||
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| WEPMB023 | Hydroforming SRF Three-cell Cavity from Seamless Niobium Tube | cavity, niobium, accelerating-gradient, SRF | 2170 |
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| We are developing the manufacturing method for superconducting radio frequency (SRF) cavities by using a hydroforming instead of using conventional electron beam welding. We expect higher reliability and reduced cost with hydroforming. For successful hydroforming, high-purity seamless niobium tubes with good formability as well as advancing the hydroforming technique are necessary. Using a seamless niobium tube from ATI Wah Chang, we were able to successfully hydroform a 1.3 GHz three-cell TESLA-like cavity and obtained an Eacc of 32 MV/m. A barrel polishing process was omitted after the hydroforming. The vertical test was carried out with very rough inside surface. We got amazing and interesting result. | |||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB023 | ||
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| WEPMB056 | CVD Deposition of Nb Based Materials for SRF Cavities | niobium, SRF, lattice, accelerating-gradient | 2241 |
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| Bulk niobium cavities are widely employed in particle accelerators to create high accelerating gradient despite their high material and operation cost. Advancements in technology have taken bulk niobium close to its theoretical operational limits, pushing the research to explore novel materials, such as niobium based alloys. Nitrides of niobium offer such an alternative, exhibiting a higher Tc compared to bulk niobium. Replacing then the niobium with a material with better thermal conductivity, such as copper, coated with thin films of nitrides in a multilayer S-I-S would lead to improved performance at reduced cost. Physical vapour deposition (PVD) is currently used to produce these coatings, but it suffers from lack of conformity. This issue can be resolved by using chemical vapour deposition (CVD), which is able to produce high quality coatings over surfaces with a high aspect ratio. This project explores the use of CVD techniques to deposit NbN thin films starting from their chlorinated precursors. The samples obtained are characterized via SEM, FIB, XRD, and EDX. | |||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB056 | ||
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| WEPMR003 | Tailoring Surface Impurity Content to Maximize Q-factors of Superconducting Resonators | cavity, niobium, simulation, factory | 2258 |
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Funding: Fermilab is operated by Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 with the United States Department of Energy. Quality factor of superconducting radio-frequency (SRF) cavities is degraded whenever magnetic flux is trapped in the cavity walls during the cooldown. In this contribution we study how the trapped flux sensitivity, defined as the trapped flux surface resistance normalized for the amount of flux trapped, depends on the mean free path. A variety of 1.3 GHz cavities with different surface treatments (EP, 120 C bake and different N-doping) were studied in order to cover the largest range of mean free path nowadays achievable, from few to thousands of nanometers. A bell shaped trend appears for the range of mean free path studied. Over doped cavities falls at the maximum of this curve defining the largest values of sensitivity. In addition, we have also studied the trend of the BCS surface resistance contribution as a function of mean free path, revealing that N-doped cavities follow close to the theoretical minimum of the BCS surface resistance as a function of the mean free path. Adding these results together we unveil that optimal N-doping treatment allows to maximize Q-factor at 2 K and 16 MV/m until the magnetic field fully trapped during the cavity cooldown stays below 10 mG. |
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| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR003 | ||
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| WEPMR019 | Development of Plasma Cleaning at Cornell University | plasma, cavity, SRF, experiment | 2302 |
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| Cornell University is developing the plasma cleaning technology as an alternative cleaning technique for SRF cavity surface preparation. In experiments, we successfully ignited the plasma in a single-cell SRF cavity. However the experiments were limited by the peak electric-fields in the RF coupler. In this paper, we show the analysis of the limitation and propose a new design of the coupler which can eliminate the limitation. | |||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR019 | ||
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