Radiation Safety at the Experimental Facilities of the Institute

Albert Fuchs

Paul Scherrer Institute CH-5232 Villigen Division for Safety and Security

Body of Abstract: The Paul Scherrer Institute (PSI) at Villigen, is a multi-disciplinary research centre for natural sciences and technology. It is one of the world\'s leading user laboratories for both the national and international scientific community, and also participates in national and international collaborations with universities and industry. The research priorities of the institute lie in the area of basic and applied physics. In order to cover the broad range of experimental possibilities the institute operates several beam facilities. First of all a 590 MeV 1.8 mA proton beam facility RING is provided, used to generate particle beams such as protons, and myons. Part of the proton beam is guided to a Source (SINQ). The generated are used as probes in various physical, chemical biological experiments and in material science. Since the year 2001 a 2.4 GeV radiation source (SLS) is operating, providing high quality photon beams for research in material science, chemistry and biology. Presently PSI, in collaboration with industry, is developing a prototype 250 MeV facility (PROSCAN) designed to be operable also in hospitals in the future. Each of these particle accelerators can be regarded as a source of radiological risk. Primary particles as well as secondaries like neutrons or radioactive nuclides give rise to environmental radioactivity and radiation doses. Therefore radiological safety is an essential aspect, not only during operation. The Swiss Radiation Rrotection Law gives the guidelines for the work. The safety of the employees, including mostly the external scientists and the environment is ranking first. At PSI the \\\"Betriebsstrahlenschutz\\\", a section of the radiation safety department is in charge of that complex task. An overview on the most important fields of practical radiological safety applied at the beam facilities at PSI will be presented. The exhaust air surveillance system, the experimental area air surveillance system, as well as the neutron, photon and electron site dosimetry will be discussed. Access to the experimental areas and the facility vaults silos is controlled by personnel safety equipment, also interacting with the machine emergency shut down system. The actual layout for PROSCAN will be presented as an example. The major differences in the practical radiation safety between the PSI proton accelerator RING and electron accelerators SLS will be discussed.