Abstract: A record structure for recording with a radiation beam uses a transparent disc or drum, a coaxial backing disc or drum and two coaxial resilient ring-shaped seals to provide an enclosure between the discs or drums. Radiation-sensitive recording material on the side of the disc or drum within the enclosure is thereby protected from ambient dust particles and other contaminations, while the gaseous or solid by-products of the inter-action between the recording material and the radiation beam in the area around which the beam impinges are substantially contained between the disc surfaces and cannot produce deposits on an objective lens used to focus the radiation beam or poison the user.