Study of the superconducting properties of Niobium in linear Accelerators

该项目的重点是研究超导特性（临界场，亚稳性，损耗等）。铌将被用来建造直线加速器中的超导谐振腔。TESLA（Tera Electronvolt Superconducting Linear Accelerator）是一个电子伏特超导直线加速器，最初的总能量为500 GeV，可扩展到800 GeV。TESLA计划整合一个X射线激光实验室，这将允许探测物质的快速动态过程，如生物和化学反应以及物质相变。铌是超导加速结构的选择。在过去的10年中，腔体性能的改善使TESLA在成本上与其他项目相比具有竞争力，所有项目都使用正常导体。超导技术的主要优点是产生高质量的束，这对对撞机和XFEL都非常重要。TESLA需要具有极限性能的腔体。铌的超导特性的研究是推动腔体向更高性能发展的关键。为此，我们希望在这项工作中：铌的腔材料处理不同的方式，研究线性表面电阻和潜在的损失机制，并探讨它们的关系，动态驱动的涡旋物质。

The project is focused on the study of the superconducting properties (critical fields, metastability, losses, etc...) of niobium that will be used to build superconducting resonant cavities in linear accelerators. TESLA (Tera Electronvolt Superconducting Linear Accelerator) is a project for a e+ - e- linear collider of initially 500 GeV total energy, extendable to 800 GeV. TESLA is planned to integrate an X-ray laser laboratory, which will allow to probe fast dynamic processes of matter such as biological and chemical reactions and matter phase transitions. Niobium is the choice of the superconducting accelerating structures. The improvement on the cavities performances obtained in the last 10 years made TESLA competitive in cost with the other projects, all using normal conductors. The main advantage of the superconducting technology is the production of high quality beams, which are of eminent importance for both the collider and the XFEL. TESLA needs cavities of ultimate performance. The study of the superconducting properties of niobium is crucial to push the cavities to higher performances. For this reason we want in this work to: characterise the niobium of the cavities materials processed in different ways, study the linear surface resistance and the underlying losses mechanisms and explore their relation to dynamically driven vortex matter.