Performance and upgrade of the DAFNE Beam Test Facility (BTF)

The DAFNE Beam Test Facility (BTF) at the Frascati National Laboratory of INFN (LNF) has been operational since October 2002. This facility provides electron and positron beams with tunable energy from 25 MeV to 750 MeV, while the intensity can be varied from 10/sup 10//pulse @ 0-50 Hz down to a single particle. In the last two years many experiments and beam tests have been hosted, so that the large use of the facility pushed the DAFNE staff to upgrade both the beam line, in order to improve the duty cycle, limited by frequent beam injection in the DAFNE main rings, and the diagnostic devices. The beam characteristics, the user experience and their typical measurements, the diagnostic tools developed and the available equipment are presented. Finally, we report on the facility upgrade and on operation in the new configuration.