RFBPM Windows Joining Effort Undulator System

1. RFBPM Windows Joining EffortUndulator System W. Toter, D. Bromberek, F. Depaola, L. Morrison, R. Lill, W. Berg, G. Pile, L. Erwin, J. Chen, C. Ferrari, J Bailey, D. Walters

3. Single Piece Transitions Order of Joining K1 Strongest Design Order of Joining K2 This allows windows to be jointed, tested, and selected before joining to the cavity body.

4. Designs

5. Two Piece Transition J1 J2 J3

6. Alternative 2 Piece Joints Kovar Frame for E-Beam welding window Internal Moly retaining ring External Moly retaining ring

7. Logic If a technique having 100% yield cannot be determined then the only useful approach is to be able to select good units Can a window be soldered without breaking? • Soldering without windows breakage • There are three cases: (1) zero or low yield like less than 50%, (2) some usable yield like 51% to 99%, or (3) 100 %. The results at this point is: • Sn-Ag-Cu soldering is 100% • Orotin is ~50% • Georo by itself is less than 50% • Georo with a Moly ring is 100% • Repairing a solder or braze leak • Georo • Testing has shown that its re-melt temperature is higher that initial. This allows re-running the part with repair Georo to seal any leaks. • Sn-Ag-Cu • Testing in hydrogen to repair leaks have been unsuccessful. • Removal & Replacement of Windows • No matter what joining technique is chosen: Brazing, soldering, or welding; if the windows cannot be replaced due to gross mishandling than this is a concern. • By choosing a de-mountable transition to body joint than this concern can be overcome. • Additionally if the design uses some kind of two piece design and the attachment can be machined out (without getting chips into the cavity) then any technique is usable. NO Yes Can a solder joint having a vacuum leak be repaired? Any technique that cannot be repaired should be eliminated NO Yes The only useful technique is machining it out, chips falling into cavity a major concern Can a broken window be removed and replaced? NO Yes

8. Good Georo Joint in December This was done after increasing the dimensions of the opening and braze in ANL’s furnace at 400 deg C

9. Large Moly Ring for Controlling Copper Expansion • External Moly Ring

10. Small Moly Ring for Controlling Copper Expansion • Internal Moly Ring

11. Nickel Plating Blistering

12. First Test by Altair

13. Results of SN-Au (Orotin) run at Altair

14. Orotin Samples Viewed from the Reverse Side

15. Status of EffortSelect Results 2 Piece Transition • Microwave transmission • Test of prototype parts show that small mismatch will not degrade performance • Sn-Ag-Cu • Liquid Flux RGA tests • First test used windows and copper parts, after 24 hours of baking at 150 deg C a residue of the flux is present • Liquid Flux heated with a Hot Plate • A fluxed part made leak tight joint without cracking the window • Hydrogen Gas as a flux • Test with gold plating at 220 deg C had leaks but did not crack the window. • A tests at 230 deg C showed good wetting of the copper by the solder material • Reran windows with vacuum leak at 250 deg C and was not able make it leak tight. • Window Joint • Larger dimensions • Measured 30 windows and increased dimensions by .3 mm • Test piece using Georo did not crack or leak in 1 of 1 piece • Test pieces using Orotin leaked in 3 of 3 pieces and only 1 cracked • Stress relief groove • In test pieces a .8 mm wide land was included • Test piece using Georo leaked in 1 piece of 1. • 3 test pieces using Orotin did not leak and had 1 cracked frit. • Moly retaining rings added to limit copper expansion • 2 Parts with internal Moly ring were soldered with Georo and there were no leaks • 2 Parts with external Moly ring were soldered with Georo and there were no leaks • 2 Parts with using external Moly ring (no relief groove) were soldered with Georo and there were no leaks • Plating • Nickel Only • Windows fired at 450 C in H2, found 3 parts in 8 with blisters • CPI will fire parts at 600 deg C before shipping to ANL • Gold/Nickel • Williams suggests using gold as a oxygen barrier for nickel. • Gold is very useful for soldering below 300 deg C

16. RGA Analysis of the GAH Flux Solder Samples MW=30 MW=36 MW=46 MW=60 MW=78 -Here are the peaks (30,36,46,60, & 78)

17. Results at Altair

18. Results at ANL

19. Schedule • Week ending Jan 18 • Large Moly Ring • Sn/Ag/Cu solder at 230 C in hydrogen furnace • First attempt of Laser welding • Test using Orotin at Altair • Week ending Jan 25 • Fab test parts for 2nd round of Laser welding • Sn/Ag/Cu solder at 250 C in hydrogen furnace • Results of FEA analysis on Moly rings • Initial results from Induction Heating vendor • Section parts from Altair test • Week ending Feb 1 • Moly retainer using Orotin at 320-350 C • Laser weld test parts • Send additional parts to Induction Heating vendor • Design and fab Laser test parts with improved weld prep • Week ending Feb 8 • Run tests using induction heating • Week ending Feb 15 • Meeting on Window soldering

20. Pro/Con of Designs

21. Details to the 1 Piece Transition Plan • Braze at ANL 10 transitions using Georo with the Large Moly Ring • After thermal cycling and leak checking select 5 units for shipment to the braze vendor. • Braze vendor will use [Georo or Sn-Au] braze to attach transitions to body. • Back up is to use the 5 steel transition from CPI and prep them in case they are needed.

22. Issues with this plan • While good yield has been seen with the Moly ring and Georo the question of re-running the part to seal a leak has been not shown. • Can Georo be used to reseal a leak or something else. • Is there a technique for windows removal from the transition for the purpose of rework. • The joint material for joining the transition to the body needs to determined. • Is the removal of the transition from the body, in the event of breakage, better suited to either Georo or Sn-Au. • A plan for determining these issues is ongoing.

23. End