The infrastructure for the TESLA test facility (TTF)-a status report

The TESLA collaboration is preparing the installation of a 500 MeV superconducting linear test accelerator to establish the technical basis for a future 500 GeV e⁺e^- collider. The setup consists of 4 cryomodules, each containing 8 solid niobium cavities with a frequency of 1.3 GHz. The infrastructure to process and test these cavities has been installed at DESY. The facility includes a complex of clean rooms, an ultraclean water plant and a chemical etching installation for cavity surface preparation and cavity assembly as clean as possible. To improve the cavity performance a firing procedure at 1400°C in an ultra-high vacuum furnace is foreseen. An existing cryogenic plant has been modified to cool down the cavities below 2 K and measure them in vertical and horizontal test cryostats. The RF power will be provided by a 4.5 MW klystron (pulse length 2 ms) in connection with a modulator. This system will also be used for a high peak power RF treatment to further improve the cavity performance by eliminating potential sources of field emission. The components of the complete infrastructure for the TESLA Test Facility are described and their status is reported