Magnetron sputtering of Superconducting Multilayer Nb3Sn Thin Film
Magnetron sputtering of Superconducting Multilayer Nb3Sn Thin Film Magnetron sputtering of Superconducting Multilayer Nb3Sn Thin Film
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IntroductionThe superconductor accelerator cavity is one of the most important andperspective technology for an advance accelerator. For example, the InternationalCommittee for Future Accelerators decided that the Linear Collider design had beenbased on the superconductor technology. Moreover, the accelerator operating withcontinue wave (CW) mode must use the superconductor technology in stead of thenormal conductor technology, such as the Accelerator-driven sub-critical reactorsystem (ADS), the Accelerator Transmutation of Waste (ATW), the AcceleratorProduction of Tritium (APT), and so on.In order to meet all kinds of application, the scientific world interest is now focuson further developments of new resonant cavities fabrication techniques to reduce costand improve the performance of the accelerator cavity. To realize this object, one ofthe important methods is to pursue research on new materials. The goal will be theachievement of superconducting cavity working better the Nb ones at 4.2K. Forexample, the better parameters of the T c , the surface resistance, the critical field H cand the Q value are needed.Up to now, the most possible candidate is Nb 3 Sn. The Nb 3 Sn has not only thebetter superconductivity parameters, but also the stable property and the easyfabrication. There are two methods to fabricate the superconductor cavity with theNb 3 Sn, which are including the diffusion method and the multilayer depositionmethod. In the thesis, we focus on the multilayer deposition method, and the contentof each chapter is followed:In chapter 1, we discuss why we select the Nb 3 Sn as the function material for thesuperconductor cavity fabrication.In chapter 2, we first investigate the Nb thin film deposition on the sapphire, andanalysis the result of the deposition experiment.In chapter 3, the Nb 3 Sn multilayer thin film is first deposited on the sapphire, andthen deposited on the Nb sample. The deposition experiment results are also analyzedwith T c and crystal structure.The outline of this thesis is shown as follow:1
- Page 1: UNIVERSITÀ DEGLISTUDI DI PADOVAFac
- Page 7: IndexINDEX ........................
- Page 11 and 12: Fig. 1.1 Disc-loaded traveling-wave
- Page 13 and 14: In Type-II superconductors, vortex
- Page 15 and 16: needed for preventing the supercond
- Page 17 and 18: The B1 crystal structure has a cubi
- Page 19 and 20: NbN cavities literature, is often h
- Page 21 and 22: superconducting magnet construction
- Page 23 and 24: 775°C. From the same diagram, it i
- Page 25 and 26: two types of electrons at the Fermi
- Page 27 and 28: Of course, there are some other kin
- Page 29 and 30: as shown in Fig.2.3. The four opera
- Page 31 and 32: Fig.2.8 turbomolecular pumpFig. 2.9
- Page 33 and 34: Fig. 2.14 The chamber covered with
- Page 35 and 36: Fig. 2.17 the gasket and the magnet
- Page 37 and 38: shown in Fig. 2.21 and Fig. 2.22. T
- Page 39 and 40: Fig. 2.26 The interface of the surf
- Page 41 and 42: Fig. 2.30 put the sample into the T
- Page 43 and 44: Fig. 2.34 the performance of the th
- Page 45 and 46: 1008038.5°{110}69.6°{211}sample1s
- Page 47 and 48: 2dsinθ= nλ (2.3)Fig.2.44 the diff
- Page 49 and 50: Chapter 3 Multilayer deposition of
- Page 51 and 52: 1 minute. The time of depositing mu
- Page 53 and 54: chamber 1 and is connected to the s
- Page 55 and 56: 3.2.2.2 Analysis resultⅠ The thic
- Page 57 and 58: In order to detect the component of
IntroductionThe superconductor accelerator cavity is one <strong>of</strong> the most important andperspective technology for an advance accelerator. For example, the InternationalCommittee for Future Accelerators decided that the Linear Collider design had beenbased on the superconductor technology. Moreover, the accelerator operating withcontinue wave (CW) mode must use the superconductor technology in stead <strong>of</strong> thenormal conductor technology, such as the Accelerator-driven sub-critical reactorsystem (ADS), the Accelerator Transmutation <strong>of</strong> Waste (ATW), the AcceleratorProduction <strong>of</strong> Tritium (APT), and so on.In order to meet all kinds <strong>of</strong> application, the scientific world interest is now focuson further developments <strong>of</strong> new resonant cavities fabrication techniques to reduce costand improve the performance <strong>of</strong> the accelerator cavity. To realize this object, one <strong>of</strong>the important methods is to pursue research on new materials. The goal will be theachievement <strong>of</strong> superconducting cavity working better the Nb ones at 4.2K. Forexample, the better parameters <strong>of</strong> the T c , the surface resistance, the critical field H cand the Q value are needed.Up to now, the most possible candidate is Nb 3 Sn. The Nb 3 Sn has not only thebetter superconductivity parameters, but also the stable property and the easyfabrication. There are two methods to fabricate the superconductor cavity with theNb 3 Sn, which are including the diffusion method and the multilayer depositionmethod. In the thesis, we focus on the multilayer deposition method, and the content<strong>of</strong> each chapter is followed:In chapter 1, we discuss why we select the Nb 3 Sn as the function material for thesuperconductor cavity fabrication.In chapter 2, we first investigate the Nb thin film deposition on the sapphire, andanalysis the result <strong>of</strong> the deposition experiment.In chapter 3, the Nb 3 Sn multilayer thin film is first deposited on the sapphire, andthen deposited on the Nb sample. The deposition experiment results are also analyzedwith T c and crystal structure.The outline <strong>of</strong> this thesis is shown as follow:1
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