|Title||SUPERSTRUCTURES; FIRST COLD TEST AND FUTURE APPLICATIONS|
|Abstract||Superstructures, chains of superconducting multi-cell cavities (subunits) connected by half-wavelength long tube(s) have been proposed as an alternative layout for the TESLA main accelerator. After three years of preparation, two superstructures, each made of two superconducting 7-cell weakly coupled subunits, have been installed in the Tesla Test Facility linac for the cold- and beam test. Energy stability, HOM damping, frequency and field adjustment methods were tested. The measured results confirmed expectations on the superstructure performance and proved that an alternative layout for the 800 GeV upgrade of the TESLA collider is feasible. We report on the test and give here an overview of its results. The cold test confirmed very good damping of HOMs in superstructures and thus has opened a new possible application of this concept to high current energy recovery machines. We have built two 1.5 GHz copper models of two superstructures: 2x5-cells and 2x2-cells to prove further improvement of HOM damping. This contribution presents also measured results on these models.|
Principle author first.
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