13/Nov/ mm STF2 Coupler Design Content 1.Motivation 2.40mm Design 3.“Preliminary” Result by HFSS 4.“Tentative” Conclusion 5.Future Plan This report is made by help from Kako-san and Sakai-san. Kirk

superconducting rf test facility Motivation 13/Nov/ mm 60mm DESY/FNAL Cavity PackageKEK Cavity Package TTF3 CouplerSTF2 Coupler In view of “Plug compatibility”, the use of STF2 coupler should be evaluated for 40mm diameter. What is the most simple way for this change?

superconducting rf test facility Design of 40mm STF2 Coupler 13/Nov/ Only this part should be modified for minimum change! I used HFSS for this calculation.

superconducting rf test facility HFSS modeling for each step 13/Nov/ Step 1: only cold part Step 2: full modelStep 3: bellows Bellows are Not included!

superconducting rf test facility Step 1: Only cold part without bellows 13/Nov/ mm40 mm 1.3 GHz S 11 The both types has S 11 with <-25 dB! Same structure

superconducting rf test facility Step 2: Full model without bellows 13/Nov/ mm40 mm 1.3 GHz S 11 Same structure The both types has S 11 with <-20 dB!

superconducting rf test facility Step 2: Full model without bellows 13/Nov/ mm40 mm

superconducting rf test facility Step 3: Evaluation of bellows 13/Nov/ mm40 mm 1.3 GHz (-22 dB) 1.3 GHz (-18 dB) S 11 We have to develop the smaller bellows. Same structure

superconducting rf test facility It’s no problem in RF performance for 40mm STF2 coupler! 13/Nov/ “Tentative” Conclusion at least

superconducting rf test facility 13/Nov/ Future Plan  Mechanical Design for 40mm STF2 Coupler  More important than RF calculation  Especially, inner conductor in cold part  Tuning range (1-10 x 10 6 ) to be estimated  Lower cost  If the cost is higher, it’s no meaning!

superconducting rf test facility 13/Nov/ To Do List (Simulation)  Cavity-to-Coupler coupling should be fixed  Simulated by HFSS or CST Studio  Full model simulation with Doorknob  Simulated by HFSS or CST Studio  Test bench simulation with Waveguide  Simulated by HFSS or CST Studio  Multipactoring  Simulated by CST Studio or TRACK-3P or OMEGA-3P  Others (?)

superconducting rf test facility 13/Nov/ To Do List (Mechanical Design)  Inner Conductor  Inner Conductor Bellows in cold part  Doorknob

superconducting rf test facility Thank you for your attention! 13/Nov/