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40mm STF2 Coupler Design
Content1. Motivation2. 40mm Design3. “Preliminary” Result by
HFSS4. “Tentative” Conclusion5. Future Plan
This report is made by help from Kako-san and Sakai-san. Kirk
superconducting rf test facilityMotivation
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40mm 60mm
DESY/FNAL Cavity Package KEK Cavity Package
TTF3 Coupler STF2 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 facilityDesign of 40mm STF2 Coupler
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Only this part should be modified for minimum change!
I used HFSS for this calculation.
superconducting rf test facilityHFSS modeling for each step
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Step 1: only cold partStep 2: full model Step 3: bellows
Bellows are Not included!
superconducting rf test facility
Step 1: Only cold part without bellows
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60 mm 40 mm
1.3 GHz 1.3 GHzS11 S11
The both types has S11 with <-25 dB!
Same structure
superconducting rf test facility
Step 2: Full model without bellows
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60 mm 40 mm
1.3 GHz 1.3 GHzS11 S11
Same structure
The both types has S11 with <-20 dB!
superconducting rf test facility
Step 2: Full model without bellows
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60 mm 40 mm
superconducting rf test facilityStep 3: Evaluation of bellows
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60 mm 40 mm
1.3 GHz (-22 dB) 1.3 GHz (-18 dB)S11 S11
We have to develop the smaller bellows.
Same structure
superconducting rf test facility
It’s no problem in RF performance for 40mm
STF2 coupler!
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“Tentative” Conclusionat least
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Future Plan Mechanical Design for 40mm STF2 Coupler
More important than RF calculation Especially, inner conductor in cold part
Tuning range (1-10 x 106) to be estimated
Lower cost If the cost is higher, it’s no meaning!
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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 (?)
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To Do List (Mechanical Design)
Inner Conductor Inner Conductor Bellows in cold
part Doorknob
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Thank you for your attention!
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