1. MICE RF Coupler Modifications Update 4/30/2015 Allan DeMello

2. Outline Coupler To Cavity Flange Interface Coupler Support At The RF Window Loop Shortened By 40 mm Cover For Slots In The Coupler Outer Coax Tube Titanium Nitride Plating Fabrication Plan

3. The RF Coupler Will Be Rotated For Tune The Coupling The flange bolts are removed and the coupler to cavity clamp is loosened to allow the coupler to be rotated Section view of coupler

4. The Previous Version Of The Coupler To Cavity Flange Interface When the clamp is loosened in this design the coupler flange is allowed to move out of alignment with the cavity flange Section view of coupler showing the coupler and cavity flanges and the band clamp

5. The Coupler Flange Will Have A Lip To Capture The Cavity Flange

6. The Improved Version Of The Coupler To Cavity Flange Interface This flange lip will fit over the cavity flange O.D. to provide a connection for rotating the coupler The cavity flange remains un-modified New design will use a standard off-the- shelf clamp

7. The New Flange And Clamp Were Tested With A Canted Spring This plastic part is dimensionally the same as the cavity flange The complete test assembly This is a standard off-the-shelf clamp The clamp provides the force to cant the RF seal spring This plastic part is dimensionally the same as the coupler flange with the lip added

8. The Coupler Will Be Supported At The Window To Allow For Easy Tuning A brace for the RF coupler provides support for tuning after installations. It is a 304 stainless steel bar with a bronze end piece. It will utilize the existing threaded holes in the spool flange for mounting. It can be installed at any flange bolt location. Each connection is slotted for field adjustments.

9. The Original Coupler Loop

10. The Loop Has Been Shortened By 40 mm To Reduce The Loop Area To increase the tuning sensitivity the loop length has been reduced by 40 mm.

11. The Slots In The Coupler Outer Coax Tube Will Be Covered By A Split Cover Plate The plates will be pre-tinned with low temperature silver (3.5%) and tin type UHV compatible solder. The coupler tube is pre-heated before reflowing the solder. The plates are positioned and then heated with a low temperature torch until the solder re-flows

12. The Slots In The Coupler Outer Coax Tube Covered

13. A Test Of The Slot Cover Provided A Vacuum Tight Seal The soldering of the plates does not affect the titanium nitride plating on the inside surface

14. The Copper Tubing For The Outer And Inner Coax Is At LBNL The 4-1/16” diameter tubes will be cut to length for the couplers The excess will be used for set-up of the titanium nitride plating of the inside surface of the outer coax tube. The inner and outer tubes The connectors and flanges

15. The Fabrication Plan The outer coax copper tubing has been purchased and is at LBNL. The verification of the titanium nitride plating “recipe” will begin soon. A request for quote has been submitted to the LBNL shop for the fabrication of 6 complete sets of the coupler components. A work order will be placed as soon as the quote is complete. The coupler assembly will start after the fabrication of the components is complete.

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