Apparatus for radiation curing of decorative and protective coatings on the exterior of a can or other tubular article is constructed with a plurality of ultraviolet lamps, each of which is disposed between two runs or flights of a conveyor chain having pins that carry the articles so that each article makes two passes at each lamp to receive radiation therefrom on opposite sides of each article. Two runs of the chain are at right angles to another two runs thereof so that curing radiation impinges on the entire outer surface of the tubular article. Each lamp is disposed within an individual baffle unit including a stationary shield that surrounds a cylindrical shutter that is pivotable about its cylindrical axis between normal and standby positions. In the normal position, diametrically opposed windows of the shutter are aligned with diametrically opposed windows of the shield so that radiation from a single lamp is directed toward two flights of the conveyor chain. In the standby position, radiation opaque portions of the shutter are aligned with the windows of the shield to block radiation from reaching outside the baffle unit.