Abstract: A mobile disinfection device (200) includes a disinfection chamber (203) coupled to a propulsion system (228) configured for moving along a surface (236) to be disinfected. The disinfection chamber defines a closed distal end (205), an open proximal end (206) and a surrounding wall (207) impervious to the radiation and having opposing front and rear portions and opposing side portions, respective proximal front, rear and side edges of which are propelled by the propulsion system close to the surface to be disinfected. A radiation source (260) is mounted inside the disinfection chamber for irradiating the surface through the open proximal end. The propulsion system includes a peripheral seal (304) surrounding a proximal edge of the wall and configured to obstruct radiation that might otherwise escape from inside the disinfection chamber.