external exposure facility LIBIS LIBIS (Low dose-rate Irradiator for Biological Investigations at ISS) is a dedicated Cs-137 low dose-rate gamma irradiation facility at ISS Rome, designed to expose cell cultures at dose rates between 2 μGy/h and 20 mGy/h by varying the distance from the source (28–125 cm). All experiments are performed in safe operating conditions; the facility shares its room with the Gammacell® 40 for acute irradiations, allowing direct comparison of dose-rate effects on the same cellular systems. LIBIS is open to collaboration with all interested research groups. Located at Istituto Superiore di Sanità. Paul Schofield