Numerical Analysis of the Electrical Interconnections Between LHC Superconducting Magnets

<br><b>Sommario</b><br/>
<br><b>Riassunto della tesi</b><br/>
<br><b>Abstract</b><br/>
<br><b>1. Introduction to Superconductivity</b><br/>
1.1 Properties of Superconductors<br/>
1.1.1 Electrotechnical basis<br/>
1.1.2 Meissner-Ochsenfeld Effect<br/>
1.1.3 Thermal Properties<br/>
1.2 Theories and Models<br/>
1.2.1 ''Two Fluid'' Model<br/>
1.2.2 Classical Model: the London's equations<br/>
1.2.3 BCS Theory<br/>
1.3 Critical Parameters<br/>
1.3.1 Critical Field<br/>
1.3.2 Critical Current Density<br/>
1.3.3 Critical Frequency<br/>
1.4 Type I and Type II Superconductors<br/>
1.5 Real Superconductors and Pinning<br/>
1.6 Application<br/>
<br><b>2. Superconductivity in High Energy Physics: the LHC</b><br/>
2.1 LHC project at CERN<br/>
2.1.1 Basic Elements of Accelerator Physics<br/>
2.1.2 Lattice Layout<br/>
2.1.3 Performance<br/>
2.1.4 Main Circuit and Magnets<br/>
2.2 Interconnection BUSBARS<br/>
2.2.1 Superconducting Cables<br/>
2.2.2 Copper Profile<br/>
2.2.3 Thermal Compensation Joints<br/>
2.2.4 Manufacturing Process and Insulation<br/>
<br><b>3. A Model for the Stability of Interconnection Busbars</b><br/>
3.1 Splices: the Joints between Busbars<br/>
3.2 Numerical Model<br/>
3.2.1 Analysis of Geometry and Operating Conditions<br/>
3.2.2 1-Element Model<br/>
3.2.3 2-Element Model<br/>
3.2.4 Optimization of the Static Mesh<br/>
3.3 Heat Extraction<br/>
3.3.1 Experimental set-up measurement<br/>
3.3.2 Analysis of the Measurements<br/>
<br><b>4. Studies and Results</b><br/>
4.1 Adiabatic/1-Element Model<br/>
4.1.1 Reduction of the Dump Time of the Current<br/>
4.1.2 Effect of Copper RRR<br/>
4.1.3 Spatial Distribution of the Lack of Solder<br/>
4.2 Cooling with Superfluid Helium<br/>
4.2.1 Reduction of the Current Dump Time<br/>
4.2.2 Effect of the Cable RRR<br/>
4.2.3 Impact of the Helium Phase<br/>
4.3 Two-Element Model<br/>
4.4 FRESCA Experiment<br/>
4.4.1 The Model<br/>
4.4.2 Results<br/>
4.5 Summary of the Results<br/>
<br><b>Conclusion</b><br/>
<br><b>Appendix I: NbTi Critical Surface Fit</b><br/>
<br><b>Bibliography</b><br/>