Test of two Nb superstructure prototypes

An alternative layout of the TESLA linear collider (Technical Design Report, DESY Report No. 2001-011, 2001), based on weakly coupled multicell superconducting structures (superstructures), significantly reduces the investment cost due to a simplification in the rf system of the main accelerator. In January 1999, preparation of the beam test of the superstructure began in order to prove the feasibility of this layout. Progress in the preparation was reported frequently in Proceedings of TESLA Collaboration Meetings. Last year, two superstructures were installed in the Tesla Test Facility linac at DESY to experimentally verify methods to balance the accelerating gradient in a weakly coupled system, the stability of the energy gain for the entire train of bunches in macropulses, and the damping of higher order modes.We present results of the first cold and beam test of these two Nb prototypes.