Lilje, L.

Paper	Title	Page
MOPCH155	Performance Limitations of Tesla Cavities in the Flash Accelerator and their Relation to the Assembly Process	421
	L. Lilje DESY, Hamburg
	Several accelerator modules with superconducting cavities have been assembled for TTF. The paper reviews the performance of these structures and will try to correlate their performance to information about the assembly process. In some cases a performace degradation could be attributed to problems in this process. The introduction of additional quality control steps improved accelerator module performance. For example, the more recently assembled modules have shown the expected acceleration gradients and no vacuum leaks.
THPPA02	High-Gradient Superconducting Radiofrequency Cavities for Particle Acceleration	2752
	L. Lilje DESY, Hamburg
	The development of radiofrequency superconductivity for particle acceleration has reached a level where many projects consider its use. One of the many attractive features of these accelerating structures is to achieve very high accelerating fields efficiently. The technology has been developped to a stage where accelerating gradients of more than 25 MV/m are being implemented in accelerator modules. In single-cell test resonators even higher gradients were already achieved. To operate cavities at these gradients efficiently their frequency needs to be kept stable to reduce the need for an overhead in radiofrequency power. Introducing active elements like piezoelectric actuators allows to achieve these goals.
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