VACUUM CHAMBER FOR THE WIGGLER OF THE TAIWAN LIGHT-SOURCE AT THE SYNCHROTRON-RADIATION RESEARCH-CENTER

An aluminum vacuum chamber 3 m long and 21.5 mm high was fabricated, t ested and installed in the wiggler section of the Taiwan Light Source at the Synchrotron Radiation Research Center. The chamber was made by the extrusion method and machined to a flatness of < +/- 0.1 mm/(3) m. The inner aperture included an elliptical channel (17 mm x 80 mm) for electron beam and a pumping channel for a nonevaporable getter (NEG) strip. Two heat-treated Be-Cu springs were used to absorb the thermal expansion of the NEG strip during activation. After installation of th e wiggler chamber in the storage ring, a pressure of 0.45 nTorr was re ached after an in situ bakeout with NEG activated, The high temperatur e properties of the Be-Cu spring and the vacuum performance of the com plete chamber have been tested. No obvious influence, due to the narro w beam aperture or limited gas conductance to the beam life time was f ound. (C) 1996 American Vacuum Society.