The CTF3 Two-beam Test Stand

Abstract The Two-beam Test Stand (TBTS) has been constructed and operated at the CLIC test facility CTF3 at CERN. The TBTS comprises two parallel and independent electron beam lines and has been designed to demonstrate the feasibility of a two-beam high gradient acceleration concept as proposed for the Compact Linear Collider (CLIC). In the CLIC scheme, the RF power is extracted from a high current drive beam using RF power extraction structures while the main beam is accelerated using this RF power which is fed into high gradient high frequency normal conducting accelerating structures. The Two-beam Test Stand is a unique facility to demonstrate the feasibility of the CLIC two-beam high gradient acceleration concept and to test the individual CLIC components and complete two-beam CLIC modules. The TBTS is particularly well suited to investigate the effects on the beam of RF breakdown in the high gradient accelerating structures. We report on the design, construction and commissioning of the Two-beam Test Stand.