Zero Length Viewport, UV Grade Fused Silica, 0.63 Inch Clear Aperture, CF 1.33 Inch, 316 Stainless Steel Flange

Zero length ConFlat (CF) viewports are used for light transmission in ultra-high vacuum applications. The front face of the window sits flush or just below the flange, introducing zero additional length beyond the typical thickness of a conflat flange. The window is brazed or fused to a thin, folded metal ring. The brazed connection is compatible with ultra-high vacuum and the folded metal ring introduces enough flexibility that the windows do not crack during dissimilar thermal expansion between the window and flange. The brazed connection between window and metal allows these viewports to handle higher bakeout temperatures than viewports that contain O-rings. The outer conflat flange uses a copper gasket and knife-edges to achieve a high vacuum seal and can operate down to 10^-13 torr.

Fused silica is a high quality optics material used by default in a wide range of optical applications. It is highly transparent in the ultraviolet (UV), visible, and near infrared (NIR) regions, has high strength and scratch resistance, and resists most chemicals.

316 stainless steel is one of the least magnetic grades of stainless steel. It has a low magnetic permeability which can prevent distortion of critical magnetic fields such as those used in particle accelerators, electron beam lithography, and electron microscopy. 316 stainless steel also has very high corrosion resistance, higher than 304 stainless steel for most applications.