A WINDOW FOR INFRARED RADIATION

A window made from a MgF2 optical ceramic diffusion-welded to a stainl ess-steel rim is designed to be used in a heated apparatus with a high vacuum. The transparency band is 1-8 mum. The aperture is 70 mm, the thickness is 4 mm. The surface gas release rate at 600-degrees-C under a vacuum of approximately 10(-9) torr is less than 7 . 10(-7) torr/se c. The window is sealed in the rim by a technique combining ceramic fo rmation from a fine powder and the diffusion welding of the ceramic wi th the rim. The rim can be pressed to a vacuum-system opening with a m etal gasket.