Author: Chang, C.-C.
Paper Title Page
WEPPD019 Manufacturing and Welding Process of Straight Section of Aluminum Alloy UHV Chambers for Taiwan Photon Source 2537
  • C.-C. Chang, C.K. Chan, C.L. Chen, J.-R. Chen, G.-Y. Hsiung, S-N. Hsu
    NSRRC, Hsinchu, Taiwan
  This paper describes the manufacturing process and welding sequence for the aluminum extrusion vacuum chamber for the straight sections in Taiwan Photon Source. The straight section composes of aluminum extrusion chamber of A6063 and BPM chamber of A6061 aluminum alloys. The straightness and flatness of these extrusion chambers are controlled under 0.1mm/m and 0.2mm/m, respectively. The BPM chambers are manufactured precisely in oil-free environment, which provide clean surface and a precise sealing surface after machining. All the components are assembled in pre-aligned support system through the welding process. The aluminum chamber for 24 straight sections has been welded. The results show the straightness of < 0.15mm/m, flatness of < 0.3mm/m, and leakage rates of < 2 × 10-10 mbarl/sec. were achieved.  
WEPPD021 Optimization of the Ultra-High Vacuum Systems for the 3 GeV TPS Synchrotron Light Source 2543
  • G.-Y. Hsiung, C.K. Chan, C.-C. Chang, C.L. Chen, J.-R. Chen, C.M. Cheng, Y.T. Cheng, S-N. Hsu, H.P. Hsueh, Huang, Y.T. Huang, I.C. Sheng, L.H. Wu, Y.C. Yang
    NSRRC, Hsinchu, Taiwan
  The Taiwan Photon Source (TPS), a 3 GeV synchrotron light source, provides an ultra-low emittance of electron beam and the consequent extremely high brightness of photons. The vacuum pressure along the beam duct should be ultra-high vacuum (UHV) and even lower for reduction of the impact to the beam from the gas scattering or ion trapping troubles. Most of the outgas comes from the photon stimulated desorption (PSD) back streaming from downstream absorbers during beam operation and large area surface outgas inside the beam duct as well. Due to the anticipate request of the smallest vertical aperture of beam ducts from various insertion devices and the lowest broadband impedance through all the vacuum chambers of electron storage ring, the inner structure design and the surface treatment of vacuum chambers as well as the constraint of the back stream PSD outgas from distributed absorbers and the pumping locations should be optimized to obtain a high quality UHV system for the high stable synchrotron light source through the long period of operation. The optimized design of the vacuum chambers for the TPS will be described.  
WEPPD023 Design and Manufacture of TPS BPM Diamond-Edge Gasket 2549
  • Huang, Y.T. Huang, C.-C. Chang, C.L. Chen, J.-R. Chen, G.-Y. Hsiung, H.P. Hsueh
    NSRRC, Hsinchu, Taiwan
  TPS vacuum chamber is oil-free machined and the material is A6061T651 which the Brinell hardness is 95 kg/mm2. Beam position monitors are installed onto the bending chambers, B1 and B2 and the straight chambers, S3 and S4. The diamond-edge gasket was chosen to seal between BPM flange (SS316L) and the vacuum chamber (A6061T651). Easily manufactured, low cost and less clamping force are three main advantages of this diamond-edge gasket. This diamond-edge gasket is made of A1050H14 which has less hardness, 32 kg/mm2 and its surface roughness is well controlled under 0.8 μm because worse surface roughness probably lead to radial leak. Considering differences of thermal expansion between stainless steel and aluminium, SS304 set screws, nuts and washers are chosen to provide axial sealing force. The sealing ability of this diamond-edge gasket is reliable through tens of bake-out experiments. It is reminded that pre-torque should be sufficient to cause plastic deformation of the diamond-edge gasket and re-torque after baking 24hr and cooling down to room temperature is also important to prevent leaks resulting from loss of torque which usually happen at 100oC.