An ultra-high-vacuum mirror box with three remotely-operated water-cooled mirrors for the U13U wiggler/undulator spectroscopy branch line at the national synchrotron light source

Abstract We describe an ultra-high-vacuum mirror box with three independent remotely operated water-cooled mirrors which serve to focus a diverging input beam onto a common focal point. Each of the mirrors may be adjusted by independent rotations about two perpendicular axes in the mirror surface plane which intersect at the pole of the mirror and by linear motion along an axis orthogonal to the two rotation axes. These motions permit the surfaces of the three mirrors to lie on a common sphere, thereby forming the equivalent of a single mirror three times longer than any of the individual mirrors without the extreme cost and inherent figure error of such a lengthy mirror. The design is based on the combination of a double-axis gimbal mechanism and a linear extraction mechanism. Each mirror mechanism is fixed to a large rectangular flange attached to the mirror chamber by a special Helicoflex seal ∗∗ . All motions for each of the three mirrors are provided by stepping motors through special mechanisms with three bellows, one for a two-axis rotation and two for linear motion.