Achievement of the Vacuum System of Taiwan Photon Source

Abstract

 Commissioning of Taiwan Photon Source (TPS), a 3-GeV synchrotron light source, began in 2014 summer, observed the first light on 2014 December 31, and achieved in three months the primary goals of low emittance ∼1.6 nm rad at beam current 100 mA with lifetime 6 h and top-up operation. The dynamic pressure 1.2×10⁻⁹ Pa mA⁻¹ at accumulated beam dose 33 A h after beam cleaning and a measured broadband impedance about 0.12 Ω reflects the satisfactory vacuum performance of this electron-storage ring. The implementation of ultrahigh-vacuum systems (aluminium, length 14 m) constructed for the 24 arc-cells of TPS involved numerically controlled precise machining free of oil in an ethanol environment, cleaning with ozonized water, automatic TIG welding of aluminium chambers (large, 4 m), assembly of vacuum systems (aluminium, full length 14 m) in the clean room, baking to ultrahigh vacuum ex situ before installation, and rapid loading of the 14-m vacuum cells into the TPS tunnel with hangers for carriage and transport; associated with the engineering developments are key technologies to achieve the high quality of the ultrahigh-vacuum systems for the electron-storage ring of this accelerator light source.