The design, construction and testing of a multipole wiggler magnet titanium vacuum chamber for the SRS

A vacuum chamber is required for two new insertion devices (IDs) at the SRS. The chamber has been designed, finite element analysis performed, and a prototype constructed and successfully tested. The chamber is 1208 mm in length, it has an internal aperture of 134 mm/spl times/16 mm and a minimum wall thickness of 1 mm. The chamber has been precision machined in two halves from titanium alloy and electron beam (EB) welded in order to meet the demanding tolerances. Titanium alloy was selected in preference to more conventional ultra high vacuum (UHV) materials, due to its electron beam weldability, low distortion and outgassing rates. The design, construction and processing has been conducted to UHV standards to achieve a working pressure of 1/spl times/10/sup -9/ mbar.