1. PhD project: Development of a Ferrite-Loaded Accelerating Cavity CERN Supervisor: Dr.-Ing. Christine Völlinger TEMF Supervisor: Prof. Dr.-Ing. Harald Klingbeil From Ferrite Characterization to Preliminary Design of Ferrite Loaded Accelerating Cavity Johannes Eberhardt CERN, Beams Department / TU Darmstadt, TEMF Institute

2. 29th of April 2015 2 Motivation: Ferrite Loaded Accelerating Cavity ▪Idea: Same RF system to accelerate different types of particles → Accelerating Cavity with frequency swing 18 – 40 MHz ▪Cavity design with electromagnetic simulation program → Relative permeability and losses of ferrite as input for simulations Ferrite Cavity

3. Introduction – How does an accelerating cavity work? accelerating gap beam pipe cylindrical structure E RF H RF λ/4 29th of April 2015 3

4. Introduction – Why Ferrite Loaded? ferrite ring 29th of April 2015 4

5. Introduction – Relative Permeability Depends on: RF frequency 29th of April 2015 5

6. Introduction – Lessons learned Sample 1 Sample 2 Sample 3 Depends on: RF frequency Magnetic bias history Temperature Location in ferrite Bias field orientation Dispersive characteristics Random – degaussed Room temperature Average over volume Perpendicular to RF magnetic field 29th of April 2015 6

7. B /mT Reflection Measurement µ’(f res ) Resonant Measurement f res /MHz Q total EigenmodeSimulation f res /MHz d fres /% CalculateQ Q From Ferrite Characterisation to FLC 1-Port Reflection Measurement Resonant Measurement Simulation of Resonant Measurement 29th of April 2015 7

8. Reflection Measurement I bias B bias B /mT3540300 Reflection Measurement µ’(f res ) Resonant Measurement f res /MHz Q total EigenmodeSimulation f res /MHz d fres /% CalculateQ Q 29th of April 2015 8

9. Reflection Measurement B /mT3540300 Reflection Measurement µ’(f res )138.01.17 Resonant Measurement f res /MHz Q total EigenmodeSimulation f res /MHz d fres /% CalculateQ Q 29th of April 2015 9

10. Resonant Measurement B /mT3540300 Reflection Measurement µ’(f res )138.01.17 Resonant Measurement f res /MHz18.823.443.7 Q total EigenmodeSimulation f res /MHz d fres /% CalculateQ Q 9401046 29th of April 2015 10

11. Numerical Simulation Results Ferrite ring Teflon foil Inner conductor Outer conductor B /mT3540300 Reflection Measurement µ’(f res )138.01.17 Resonant Measurement f res /MHz18.823.443.7 Q total 9401046 EigenmodeSimulation f res /MHz18.623.143.3 d fres /%1.11.30.9 CalculateQ Q8355000 29th of April 2015 11

12. Numerical Simulation Results 29th of April 2015 12

13. Numerical Simulation Results 29th of April 2015 13

14. Preliminary Design of FLC 18 – 40MHz Simulation InputSimulation Results for V acc =1kV µ’(f res ) f res /MHz R/Q/ΩP/W 83517.63721363.3 1.17500040.946831081 Ferrite stack Beam pipe Accelerating gap Example V acc /kVP/kW 8.34.4 62.53.9 1125mm 29th of April 2015 14

15. Conclusion and Outlook ▪Measurement of relative permeability and losses of ferrite material ▪Simulation model of resonant measurements setup ▪Preliminary design of ferrite loaded accelerating cavity ▪Influence of non-uniform µ’ has to be analysed ▪RF power measurements have to be done ▪FLC model will be further elaborated 29th of April 2015 15

16. Thank you for your attention! 29th of April 2015 16

17. 14th of March 2014 | Johannes Eberhardt | 17 Preliminary Design

18. 14th of March 2014 | Johannes Eberhardt | 17 Resonant Measurement B /mT3540300 Reflection Measurement µ’(f res )138.01.17 Resonant Measurement f res /MHz18.823.443.7 Q total 9401046 EigenmodeSimulation f res /MHz d fres /% ExaminedQ ferr Q