Jan , 2008 LCLS Undulator Week Dean R. Walters 1 RFBPM Windows Joining Effort Undulator 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

Jan , 2008 LCLS Undulator Week Dean R. Walters 2

Jan , 2008 LCLS Undulator Week Dean R. Walters 3 K1K2 Au-Ge Au-Sn Au-GE Au-Sn H 2 Sn-Ag-Cu K1 K2 Order of Joining Single Piece Transitions K2K1 Au-Cu Au-Ge Au-Sn Au-Ge Au-Sn H 2 Sn-Ag-Cu Au-Sn H 2 Sn-Ag-Cu This allows windows to be jointed, tested, and selected before joining to the cavity body. Strongest Design

Jan , 2008 LCLS Undulator Week Dean R. Walters 4 Designs

Jan , 2008 LCLS Undulator Week Dean R. Walters 5 Two Piece Transition J1J2J3 Au-Ge E-Beam Au-Cu Au-Sn Laser Au-Ge H 2 Sn-Ag-Cu Other H 2 Sn-Ag-Cu J1 J3 J2

Jan , 2008 LCLS Undulator Week Dean R. Walters 6 Alternative 2 Piece Joints Internal Moly retaining ring Kovar Frame for E- Beam welding window External Moly retaining ring

Jan , 2008 LCLS Undulator Week Dean R. Walters 7 Logic 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. Can a window be soldered without breaking? Can a solder joint having a vacuum leak be repaired? Can a broken window be removed and replaced? Any technique that cannot be repaired should be eliminated If a technique having 100% yield cannot be determined then the only useful approach is to be able to select good units The only useful technique is machining it out, chips falling into cavity a major concern NO Yes NO

Jan , 2008 LCLS Undulator Week Dean R. Walters 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

Jan , 2008 LCLS Undulator Week Dean R. Walters 9 Large Moly Ring for Controlling Copper Expansion External Moly Ring

Jan , 2008 LCLS Undulator Week Dean R. Walters 10 Small Moly Ring for Controlling Copper Expansion Internal Moly Ring

Jan , 2008 LCLS Undulator Week Dean R. Walters 11 Nickel Plating Blistering

Jan , 2008 LCLS Undulator Week Dean R. Walters 12 First Test by Altair

Jan , 2008 LCLS Undulator Week Dean R. Walters 13 Results of SN-Au (Orotin) run at Altair

Jan , 2008 LCLS Undulator Week Dean R. Walters 14 Orotin Samples Viewed from the Reverse Side

Jan , 2008 LCLS Undulator Week Dean R. Walters 15 Status of Effort Select Results 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 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.

Jan , 2008 LCLS Undulator Week Dean R. Walters 16 RGA Analysis of the GAH Flux Solder Samples -Here are the peaks (30,36,46,60, & 78) MW=78MW=60 MW=46 MW=36 MW=30

Jan , 2008 LCLS Undulator Week Dean R. Walters 17 Results at Altair S/NTest Location MaterialLeakGlassFritFiller ThkJoint Prep Plating 2a-68AltairSn-Au 355 CYesOK SingleStdAu 2a-69AltairSn-Au 355 CNoOK SingleGrvAu 2a-90AltairSn-Au 355 CYesCrkOKSingleStdNi 2b-61AltairSn-Au 355 CNoOK SingleGrvAu 2b-67AltairSn-Au 355 CYesOK SingleStdAu 2b-89AltairSn-Au 355 CNoOKCrkSingleGrvNi 91AltairSn-Au 320 CNoOK DoubleStdNi 92AltairSn-Au 320 CYesCrk DoubleGrvNi 93AltairSn-Au 320 CNoOK SingleStdNi 94AltairSn-Au 320 CNo?- OKCrkSingleGrvNi 95AltairSn-Au 320 CYesCrk SingleStdNi 96AltairSn-Au 320 CYesCrk SingleGrvNi

Jan , 2008 LCLS Undulator Week Dean R. Walters 18 Results at ANL Date or S/N Test Location MaterialLeakGlassFritFiller ThkJoint Prep Plating 72ANLSn-Ag-Cu 230 CYesOK SingleGrvAu 62ANLSn-Ag-Cu 230 CYesOK SingleGrvAu 1/18ANL RflwSn-Ag-Cu 250 CYesOK SingleGrvAu 1/18ANLSn-Ag-Cu 230 CYesOK DoubleGrvAu 184SANLGeoro 400 C Lg MoNoOKSplDoubleGrvNi 185SANLGeoro 400 C Lg MoNoOKSplDoubleGrvNi 1/22ANL -2Georo 400 C Lg MoNoOK DoubleLg StdNi 1/22ANL -2Georo 400 C Lg MoNoOK TripleLg StdNi

Jan , 2008 LCLS Undulator Week Dean R. Walters 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 2 nd 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 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

Jan , 2008 LCLS Undulator Week Dean R. Walters 20 Pro/Con of Designs DesignProCon 1 Piece Design Faster to bring into productionMore difficult to replace Window Plan uses pre-tested windowModification to parts required Can use existing partsNeed low temperature joint to attach transition to body 2 Piece Design Ability to pre-test window jointMust make new transitions Easiest to replace windowLonger Lead Time Potential to have interchangeable parts Need to develop weld process CPI Window Assy CPI will deliver leak tight Window assemblies Copper plating unknown Hard braze expected to be highly reliable CPI parts will be costly and take the longest to produce CPI responsible for qualityHave seen evidence of questionable CPI quality

Jan , 2008 LCLS Undulator Week Dean R. Walters 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.

Jan , 2008 LCLS Undulator Week Dean R. Walters 22 Issues with this plan 1.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. 1.Can Georo be used to reseal a leak or something else. 2.Is there a technique for windows removal from the transition for the purpose of rework. 2.The joint material for joining the transition to the body needs to determined. 1.Is the removal of the transition from the body, in the event of breakage, better suited to either Georo or Sn- Au. 3.A plan for determining these issues is ongoing.

Jan , 2008 LCLS Undulator Week Dean R. Walters 23 End