1. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 1 LCLS Injector RF Gun: Design, Fabrication & Tuning Plans D. H. Dowell, SLAC Injector RF Review: November 3, 2004 Injector Requirements Detail of Gun to Linac Region Load Lock, Gun & Solenoid Description Some technical issues RF Gun Status (design & procurement) Current fabrication & procurement plans Schedule Gun tuning Cooling system (preliminary) Summary and Conclusions

2. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 2 LCLS Injector Performance Requirements:

3. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 3 Gun to Linac Region Cathode Load Lock RF Gun Gun Solenoid Gun Spectrometer Linac Solenoid L0-1 Porcupine Cathode Clamp

4. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 4 Load Lock Conceptual Design Stage for Cathode Insertion / Alignment Treatment / Transfer Chamber Cathode Holder UHV All Metal Gate Valves RF gun

5. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 5 S20 Alcove Floor Plan Laser Penetration S20 Alcove includes a Load Lock Room for Installing & Processing Cathodes in Load Lock

6. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 6 Dual Feed RF Gun and Solenoid Dual Feed/Racetrack Design Corrects RF Fields to Second Order Solenoid Design Includes Both Dipole and Quadrupole Field Correctors

7. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 7 Gun Solenoid will have Dipole and Quadrupole Correction Coils Measurements of Gun Solenoid Multipole Fields Solenoid being designed with both dipole and quadrupole correcting coils

8. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 8 RF Gun Fabrication & Acquisition (Near Term) April 2004: Released Request for Information to two vendors April 2004: Begin work on RF design for gun May 2004: Vendors respond with budgetary quotes and schedules for engineering and fabrication of load lock and RF gun. August 2004: Technical meetings with vendors at SLAC Now: Finalize RF design Now: Write Request for Proposal and send to vendors Recent Decision: Load Lock prototype developed using SBIR with AES (Advanced Energy Systems)

9. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 9 RF Gun Fabrication & Acquisition: Assumptions and Plans Load Lock prototype developed using SBIR with AES (Advanced Energy Systems) Gun design should be compatible with future load lock SLAC does RF design for gun, provides design to vendor Vendor engineers gun including thermal analysis and design of cooling system Vendor cold tests, fabricates and re-tests gun Technical reviews at both SLAC and Vendor facility SLAC participates with Vendor in RF and thermal tests of the gun and cooling system Vendor may participate in high power RF commissioning of gun at SLAC Vendor Delivers: Hardware/Software: RF gun cooling system including plumbing hardware used to test gun & cooling system computer control source code. Documentation: All engineering drawings funded by this project especially those of gun and cooling system Written progress reports on contract progress Written reports of rf and thermal tests. Reports should include raw data acquired during tests.

10. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 10 Gun and L0-1 needed for installation: October 2006 LCLS Injector Schedule

11. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 11 Machining, Tuning & Brazing the RF Gun Under-machine rf surfaces ~0.010” Clamp together and perform rf cold tests. Based on rf tests machine surfaces as required Re-do rf cold tests Iterate rf tests and machining until gun on resonance and balanced. Perform time-domain and frequency-domain measurements of 0- and pi-modes, bead drop, needle pull, etc. Braze gun Should a lower temperature braze be used to reduce softening of Cu? Use glidcop instead of Cu? (prefer Cu) Minimize number of brazes Assemble gun with dual feed waveguide Perform time-domain and frequency-domain measurements of 0- and pi-modes, bead drop, needle pull, etc. Install on solenoid. Align rf and magnetic centerlines

12. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 12 Balancing the Dual RF Feeds Required tolerance between feeds (assume similar to L0-1 dual feed): Phase <3 degree (s-band) Amplitude <2% Machine to fit Phase shift per length of waveguide: 1deg-sband=278microns Options for balancing feeds: Deform (squeeze) a section of the waveguide Phase shift due to temperature is small For meter long waveguide section: 0.046deg-sband/deg-F

13. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 13 Dual Feed Using Standard Waveguide Components

14. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 14 RF Gun Cooling System Cooling Tower Water Chiller Near Gun Temperature Controller RF Gun Temp Meas Left Waveguide Feed Temp Monitor Right Waveguide Feed Waveguide Water

15. David H. Dowell Injector RF Design Reviewdowell@slac.stanford.edu November 3, 2004 15 Summary and Conclusions Reviewed Load Lock (LL), gun and gun solenoid requirements and constraints Gun design compatible with future LL Gun & solenoid designed as a single assembly for easy replacement with future gun S20 Alcove includes a Load Lock Room for cathode development Build prototype LL with SBIR with AES Present gun fabrication plan: SLAC designs gun RF geometry Vendor does thermal & mechanical engineering Vendor fabricates and cold tests gun Progress and technical reviews at SLAC and Vendor facility Vendor delivers gun, documentation Gun needed by Oct 2006 for installation Described machining, tuning & brazing process Control of amplitude & phase between the dual feeds Proposed cooling system for gun and dual feed waveguide