Ultra High Vacuum Beryllium Window Assemblies 1. What is a safe way to tighten a Conflat-style flange with a beryllium window in it?
• First, insert all of the bolts and tighten them by hand. • Second, tighten opposite bolts (for example, at the 12 o’clock and 6 o’clock position) gently, turning each of the bolts by no more than one-eighth of a turn after first feeling resistance. • Now tighten the set of bolts closest to 90º from the first ones (for example, at the 3 o’clock and 9 o’clock positions) in the same fashion, again turning each bolt by no more than one-eighth of a turn after first feeling resistance. • Then, tighten the next pair of bolts that are in between these bolts (for example, at the 1:30 and 7:30 position) in the same fashion. • After all of the bolts have been tightened this way, go back in the same order and tighten the bolts another quarter turn. • Keep going around the flange in this pattern, being gentle with each bolt, until the faces of the two Conflat flanges meet all the way around. Light should not be visible between the sides of the flange.
