L0-1 Design, Manufacturing & Testing R. F. Boyce, SLAC RF Technical Review, November 3, 2004

1. L0-1 Design, Manufacturing & TestingR. F. Boyce, SLACRF Technical Review, November 3, 2004 L0-1 Design Specifications Engineering Constraints and Assumptions Engineering Drawings of New Input Cells Detail of RT geometry Dual feed assembly Fabrication Process Tuning the New Cells Tuning the Dual Input High Power RF Circuit Schedule Summary and Conclusions

2. L0-1 RF Design Specifications Coupler Design For The LCLS Injector L0-1 Structure Zenghai Li, Lynn D. Bentson, David H. Dowell, Cecile Limborg, John Schmerge, Liling Xiao LCLS Technical Report, in progress

3. Engineering Constraints and Assumptions • Dual RF Input Feed (eliminates dipole kick) • Race Track Design (eliminates quadrupole field) • Solenoid has to fit over RF flanges and supports • Modify an existing SLAC structure • Cut off two cells and replace with new coupler assembly

4. Dual Feed Parts: Race track cell and adjacent cellSLAC Drawing PF-380-804-09

5. Constraints on the Dimensions of the Solenoid Outer radius Inner diameter Length

6. Procedure for Cutting Existing Structure • In 1985 Carl Rago shortened structures from 10 feet to 9 ½ feet as shown on SLAC Drawing SA-750-214-02 Cut the structure between the irises and machine the end back to the iris Their cuts Our cut

7. New Coupler Assembly • Mating features will be identical to those used for the 9 ½ foot shortened structures. Location of braze points for the tuning studs. Mating surface to braze to the modified structure.

8. Fabrication Process • Fabricate the parts and cut the existing structure • Cold RF test of parts before brazing dual feed sub assembly • Re-machine parts as required, iterate with cold tests • Braze dual feed subassembly • Cold test brazed subassembly with cut structure • Final braze of subassembly to cut structure • Final RF tests

9. Tuning the L0-1 Structure • Proposed design with push-pull studs • NLC design using slide hammer studs • Standard SLAC technique using hydraulic pinch

10. Proposed L0-1 Tuning Studs • The studs are brazed to the wall of the cell and captured by a hollow adjusting screw which is turned in or out for the adjustment process. Stud Hollow screw Threaded housing All tuning parts are stainless steel with silver plated threads Braze to copper cell

11. NLC Standard HDDS Cell Tuning The tuning stud is attached to a slide hammer for the adjustment process

12. Tuning of a Standard SLAC Structure A hydraulic press was moved to each cell and pinched it according to a well know process. This was done as part of a mass production procedure.

13. Dual Feed RF High Power RF Circuit Directional Couplers Pumps Supports Dual input feeds are balanced on the bench and the Directional Coupler signals are recorded and documented for future checks.

14. Tolerances on Dual Feed Waveguide and Coupling Holes Coupler Design For The LCLS Injector L0-1 Structure Zenghai Li, Lynn D. Bentson, David H. Dowell, Cecile Limborg, John Schmerge, Liling Xiao LCLS Technical Report, in progress

15. LCLS Injector and Linac Schedule Gun and L0-1 needed for installation: October 2006

16. Summary and Conclusions • L0-1 accelerator section • RF design finished • Engineering design in progress • Manufacturing processes are being researched • Completed accelerator section needed for October 2006 installation