RADIATION AND LASER SAFETY SYSTEMS FOR THE FERMI FREE ELECTRON LASER

FERMI is a Free Electron Laser (FEL) users facility based on a 1.5 GeV electron linac. The personnel safety systems allow entering the restricted areas of the facility only when safety conditions are fulfilled, and set the machine to a safe condition in case any dangerous situation is detected. Hazards are associated with accelerated electron beams and with an infrared laser used for pump-probe experiments. The safety systems are based on PLCs providing redundant logic in a fail-safe configuration. They make use of a distributed architecture based on fieldbus technology and communicate with the control system via Ethernet interfaces. The paper describes the architecture, the operation modalities and the procedures that have been implemented. The experience gained in the recent operation is also reported.