A proposal for a TESLA accelerator module test facility

The Tera-eV Energy Superconducting Linear Accelerator (TESLA), a 32 km long superconducting linear electron/positron collider of 500 GeV (upgradeable to 800 GeV) centre of mass energy, presently in the planning phase at DESY, will consist of about 21000 superconducting RF-9-cell cavities of pure Niobium, cooled in a 2.0 K helium bath. The cavities will be assembled in groups of 12 in about 16-17 m long cryostats (cryomodules). Among other things, the cryomodules will be equipped with thermal shields at 40/80 K and 5-8 K temperature levels respectively.Before their installation in the TESLA tunnel, the accelerator cryomodules have to be qualified after the assembly in random tests. The qualification includes the check of the general mechanical dimensions and the measurement of the cryogenic performance of all systems, in particular, the performance of the cavities.In addition, all about 21000 single cavities have to be tested before the assembly in the cryomodules at a rate of about 24 per day.The paper presents the layout of the test facility and, in particular, the layout of the helium distribution system and the test benches