1. A U.S. Department of Energy Office of Science Laboratory Operated by The University of Chicago Argonne National Laboratory Office of Science U.S. Department of Energy LCLS Undulator Vacuum Chamber Design Soon-Hong Lee Advanced Photon Source

2. Pioneering Science and Technology Office of Science U.S. Department of Energy Undulator Systems Review, March 3-4, 2004 Argonne National Lab 2 – Small Vertical Aperture (5 mm) and Thin wall (<0.5 mm) External Dimension: 6 mm OD x 3.42 m long (to fit within a 6.35 mm gap) –Stable Geometry (No Vacuum deformation) –High Conductivity Inner Surface To minimize the electric resistive wake-field effects –Low Surface roughness, Ra < 100 nm (h: ~100 nm, g: ~100  m) To minimize the surface roughness wake-field effects – High Melting Temperature To survive during direct primary beam exposure –Low Pressure and Low out-gassing rate (pumping only in undulator gap) CDR Vacuum Chamber Requirements

3. Pioneering Science and Technology Office of Science U.S. Department of Energy Undulator Systems Review, March 3-4, 2004 Argonne National Lab 3 1) SS 316L tubing + Ni Coating + E.P. + Copper Coating + E.P. OFHC seamless Cu tubing + E.P. SS 316L plate/strip + Machining + E.P. + Coating + Welding + Annealing Al Extrusion + E.P. Vacuum Chamber Design Options

4. Pioneering Science and Technology Office of Science U.S. Department of Energy Undulator Systems Review, March 3-4, 2004 Argonne National Lab 4 Vacuum Chamber Design I – Tube option Concept I 1.Ni-Coating to mirror-finished SS 316L Tube and E.P. 2.Cu-coating and E.P. 3.E-Beam welding to SS horizontal support plate 4.TIG welding to strong-back vertical plate (or Clamping using fasteners) Concept II 1.Electro-polishing of OFHC Cu Tube (As-drawn tube) 2.E-Beam tack welding to Cu plate 3.Brazing to SS horizontal support plate 4.TIG welding to strong-back vertical plate (or Clamping using fasteners)

5. Pioneering Science and Technology Office of Science U.S. Department of Energy Undulator Systems Review, March 3-4, 2004 Argonne National Lab 5 Concept I 1.Machining 4-mm thick plates for beam aperture opening 2.Eletropolishing & Cu-Coating 3.E-Beam welding at both sides 4.E-Beam to SS horizontal plate 5.TIG welding to strong-back vertical plate (or Clamping using fasteners) Vacuum Chamber Design II – Box Option Concept II 1.Machining 8-mm thick plates for welding seats 2.Bend SS mirror-finished strip 3.Cu-coating to bended strip and E.P. 4.E-Beam welding to machined plate 5.TIG welding to strong-back vertical plate (or Clamping using fasteners)

6. Pioneering Science and Technology Office of Science U.S. Department of Energy Undulator Systems Review, March 3-4, 2004 Argonne National Lab 6 Chamber DesignsAdvantagesDisadvantages SS 316L tube +Ni Coating + E.P. +Cu Coating + E.P. - Low surface finished tubing ( ~ 5 Ra Sumiclean & Valex) - High melting temperature ( ~ 1670K) - Low out-gassing rate - Not easy to handle, install and align without loosing aperture from bends and dents - Low conductivity  Coating required - Not easy to coat the copper - Not easy to achieve 4 Ra surface finish - Not easy to measure surface roughness OFHC Cu tube + E.P. - High conductivity (100%)  Coating not required - Low out-gassing rate comparable to stainless steel - Not easy to handle, install and align without loosing aperture from bends and dents - Low melting temperature ( ~ 1358K) - Not easy to achieve 4 Ra surface finish - Not easy to measure surface roughness SS 316L plate/strip + Machining + Welding + Annealing - High melting temperature ( ~ 1670K) - Low out-gassing rate - Self-support mechanism - Can measure surface roughness before welding - Low conductivity  Plating required - Technical challenges in machining and welding - Requires a post-weld annealing - Out-gassing surface increased Comparison of Vacuum Chamber Designs

7. Pioneering Science and Technology Office of Science U.S. Department of Energy Undulator Systems Review, March 3-4, 2004 Argonne National Lab 7 Measurement Instrument Tube Materials As-Received Roughness (nm) Cu-Coating Thickness (  m) After Cu-Coating Roughness (nm) After Electro- polishing (nm) AFM (area)SS 316L10.1 ~ 24.6--- OFE Cu188.1 ~ 424.5N/A - ProfilometerSS 316L48.30 ~ 313.47.02 ~ 16.82378.0 ~ 2,018.0- OFE Cu71.45 ~ 412.5N/A 75.3 ~ 386.7 Vacuum Chamber Development – Tube option As-received SS 316L TubeAs-received OFHC Cu Tube 20 x 20  m 50 x 50  m 100 x 100  m 3D-100 x 100  m (24.64nm Ra) (10.07nm Ra) (16.15nm Ra) 20 x 20  m 50 x 50  m 75 x 75  m 3D-75 x 75  m (297.98nm Ra) (317.49nm Ra) (207.98nm Ra) Performed Cu-Coating tests with 1-m long SS 316L tube Performed electro-polishing tests with 12 ft long OFHC Cu tube - Difficult to coat the copper - Difficult to achieve 4 Ra surface finish - Not easy to achieve 4 Ra surface finish

8. Pioneering Science and Technology Office of Science U.S. Department of Energy Undulator Systems Review, March 3-4, 2004 Argonne National Lab 8  Criteria - Maximum Displacement < 10  m (?) - Maximum Stress < 69MPa (Safety factor w.r.t. yield stress: 3.0) ApertureMaximum Displacement Maximum Stress Remarks 10 mm (H) x 5 mm (V) – Strip 0.52  m 8.15MPaSmall aperture 15 mm (H) x 5 mm (V) – Strip 5.86  m 41.7MPaAcceptable 20 mm (H) x 5 mm (V) – Strip 19.2  m 106.4 MPaOut of criteria 10 mm (H) x 5 mm (V) – U-profile 2.22  m 35.8MPaSmall aperture 12 mm (H) x 5 mm (V) – U-profile 3.72  m 42.1MPaAcceptable 15 mm (H) x 5 mm (V) – U-profile 9.40  m 84.2MPaOut of criteria 20 mm (H) x 5 mm (V) – U-profile 27.3  m 115.7MPaOut of criteria 10 mm (H) x 5 mm (V) aperture- Strip type Maximum Displacement: 0.52  m Maximum Stress: 8.15MPa 20 mm 6 mm Vacuum Chamber Development – Box option Stress Analysis 20 mm (H) x 5 mm (V) aperture – Strip type Maximum Displacement: 19.2  m Maximum Stress: 106.4MPa 6 mm 25 mm

9. Pioneering Science and Technology Office of Science U.S. Department of Energy Undulator Systems Review, March 3-4, 2004 Argonne National Lab 9 Global Sensitivity to horizontal aperture size 15 mm (H) x 5 mm (V) aperture – Strip type Maximum Displacement: 7.60  m Maximum Stress: 59.9MPa ~102.5 mm 6 mm Global Sensitivity Study Max. von Mises stress vs. horizontal aperture / Max. displacement vs. horizontal aperture 16.5 mm16.7 mm 69 MPa 10  m

10. Pioneering Science and Technology Office of Science U.S. Department of Energy Undulator Systems Review, March 3-4, 2004 Argonne National Lab 10 3D –ProMechanica Model Applied Loads & Constaints Vacuum Chamber Analysis – Support structure 15 mm (H) x 5 mm (V) aperture – Strip with Strong-back Support Maximum Displacement: 18.88  m Maximum Stress: 48.3MPa

11. Pioneering Science and Technology Office of Science U.S. Department of Energy Undulator Systems Review, March 3-4, 2004 Argonne National Lab 11 6 mm  0.1 8 mm  0.2 Cu-Coated on mirror-finished SS 316L strips (1.5 mm thick) 4 x E-Beam UHV Welding Leak Check I Vacuum Chamber Prototypes SS316L OFHC Cu Cu-SS Brazing Cu-Cu E-beam Tack Welding II Prototype I Prototype II Machining Both Surfaces