Application of a Matsumoto-Ohtsuka-type vacuum flange to beam ducts for future accelerators

Abstract

The Matsumoto-Ohtsuka (MO)-type vacuum flange, which can provide a gapless connection and a highly reliable electric contact between flanges, was studied experimentally for a possible application to beam ducts for high-current accelerators, where the apertures have a complicated structure, such as the combination of a beam channel and one or two flat rectangular antechambers. In spite of the complex aperture, test flanges showed a good vacuum-sealing property. Vacuum sealing was successfully achieved with a reasonable fastening torque (15–20Nm), and remained sealed after baking at 250°C for 24h. A twist between flanges of up to about 5mrad was also manageable. A pseudoelastic structural analysis well reproduced the observed deformation of the flange. This analysis should be available for optimizing the flange structure. The MO-type vacuum flange was found to be promising for connecting flanges of the beam duct with a complicated aperture in future accelerators. The flange will also be available as a compact vacuum flange in cases where a complex aperture is required.