From Ferrite Characterization to Preliminary Design of Ferrite

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

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

Introduction – How does an accelerating cavity work? accelerating gap cylindrical structure beam pipe HRF ERF λ/4 29 th of April 2015 3

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

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

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

From Ferrite Characterisation to FLC 1 -Port Reflection Measurement Resonant Measurement Simulation of Resonant Measurement B/m. T Reflection Measurement µ’(fres) Resonant Measurement fres/MHz Qtotal Eigenmode Simulation fres/MHz dfres/% Calculate Q 29 th of April 2015 Q 7

Reflection Measurement B/m. T 35 40 300 Reflection Measurement µ’(fres) Resonant Measurement Bbias fres/MHz Qtotal Eigenmode Simulation Ibias fres/MHz dfres/% Calculate Q Q 29 th of April 2015 8

Reflection Measurement ▪ B/m. T 35 40 300 Reflection Measurement µ’(fres) 13 8. 0 1. 17 Resonant Measurement fres/MHz Qtotal Eigenmode Simulation fres/MHz dfres/% Calculate Q Q 29 th of April 2015 9

Resonant Measurement B/m. T 35 40 300 Reflection Measurement µ’(fres) 13 8. 0 1. 17 Resonant Measurement fres/MHz 18. 8 23. 4 43. 7 Qtotal 9 40 1046 Eigenmode Simulation fres/MHz dfres/% Calculate Q Q 29 th of April 2015 10

Numerical Simulation Results B/m. T 35 40 300 Reflection Measurement µ’(fres) 13 8. 0 1. 17 Resonant Measurement Teflon foil Ferrite ring Outer conductor fres/MHz 18. 8 23. 4 43. 7 Qtotal 9 40 1046 Eigenmode Simulation Inner conductor fres/MHz 18. 6 dfres/% 1. 1 Calculate Q Q 29 th of April 2015 8 23. 1 43. 3 1. 3 0. 9 35 5000 11

Numerical Simulation Results 29 th of April 2015 ▪ 12

Numerical Simulation Results ▪ 29 th of April 2015 13

Preliminary Design of FLC 18 – 40 MHz Ferrite stack Accelerating gap Beam pipe 1125 mm Simulation Input Simulation Results for Vacc=1 k. V µ’(fres) fres/MHz Example R/Q/Ω P/W Vacc/k. V P/k. W 8 35 17. 6 37 213 63. 3 8. 3 4. 4 1. 17 5000 40. 9 4683 108 1 62. 5 3. 9 29 th of April 2015 14

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 29 th of April 2015 15

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

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

Resonant Measurement ▪ B/m. T 35 40 300 Reflection Measurement µ’(fres) 13 8. 0 1. 17 Resonant Measurement fres/MHz 18. 8 23. 4 43. 7 Qtotal 9 40 1046 Eigenmode Simulation fres/MHz dfres/% 14 th of March 2014 | Johannes Eberhardt | 17 Examined Qferr