U.S.-Federal Republic of Germany Cooperative Research in High-Temperature Superconductivity

该奖项支持教授艾伦M。大学的波蒂斯 加州伯克利分校的高温合作研究 超导与教授赫尔穆特皮尔，系 伍珀塔尔大学物理系。 他们共同关心的是 开发高质量的耐高温薄膜和涂料 用于各种应用超导体 在微波频率下工作的加速器腔。 质量 这些材料在高微波功率水平下劣化。 与D博士一起W.洛斯阿拉莫斯国家实验室的库克说， 他们正在开发一个详细的微波通量理论模型 渗透性和表面电阻，也正在进行仔细的 这两种现象的测量。 微波的发展 粒子加速器的空腔主要由皮尔博士领导 和他的学生 在其他任何地方都没有类似的经验。 Portis博士为合作带来了在 高温超导体的微波特性 他们的目标 是识别损失过程并努力消除它们， 以便获得保持其高质量材料 微波功率水平。 超导体中微波临界态的验证将 具有重要的科技效益。 它将 表明超导体中的微波过程 比想象的要快，需要重新检查 我们关于磁通穿透第二类超导体的一些想法。 它还可以通过识别高功率下的表面质量， 观察到的表面电阻的功率依赖性的起源， 高温超导体 如果损失机制 持续到微波频率范围内，很可能有 将这些材料用于高频信号的机会- 处理. 因此，一种机制，创造了一个问题， 加速器可以提供一个完全不同的机会， 域

This award supports Professor Alan M. Portis of the University of California at Berkeley for collaborative research on high temperature superconductivity with Professor Helmut Piel, Department of Physics, University of Wuppertal. They share an interest in the development of high quality films and coatings of high temperature superconductors for a variety of applications including particle accelerator cavities operating at microwave frequency. The quality of these materials deteriorates at high microwave power levels. Together with Dr. D. W. Cooke of the Los Alamos National Laboratory, they are developing a detailed theoretical model of microwave flux penetration and surface resistance and are also undertaking careful measurements of both phenomena. The development of microwave cavities for particle accelerators has largely been led by Dr. Piel and his students. There is no comparable experience anywhere else. Dr. Portis brings to the collaboration outstanding expertise in the microwave properties of high temperature superconductors. Their goal is to identify the loss processes and to work for their elimination, so as to obtain materials that maintain their quality at high microwave power levels. Verification of a microwave critical state in superconductors would have important scientific and technological benefits. It would indicate that microwave processes in superconductors are much faster than has been thought possible, requiring reexamination of some of our ideas of flux penetration into type II superconductors. It would also improve surface quality at high power by identifying the origin of the observed power dependence in surface resistance in high temperature superconductors. If the loss mechanism does persist into the microwave frequency range, there may well be opportunities for using these materials for high frequency signal- processing. Thus a mechanism that creates a problem for particle accelerators may provide opportunities in an entirely different domain.