1. Building a Second Harmonic Radio Frequency Cavity for the Booster Maggie Lankford SIST Intern 2015 The College of Wooster 4 August 2015

2. Outline 1.Radio Frequency Cavity Basics 2.Cavity Tuning 3.Calculating Permeability 4.Comparison Between Real and Model Cavity 5.Power Amplifier Basics 6.Building a Temperature Probe 8/04/2015Maggie Lankford |2

3. Radio Frequency (RF) Basics 8/04/2015Maggie Lankford |3 Short Beamline Outer Conductor Inner Conductor Accelerating Gap B-Field E-Field

4. Tuning the Cavity 8/04/2015Maggie Lankford |4 v: speed of light in medium c: speed of light in vacuum µ: permeability ϵ: permittivity λ: wavelength ω: angular frequency

5. Tuning the Cavity (cont.) 8/04/2015Maggie Lankford |5 Outer Conductor Inner Conductor Ferrite Rings Solenoid

6. Why Second Harmonic Cavity? 8/04/2015Maggie Lankford |6 Use wave physics to create a more square wave for injection A rectangular bucket has larger area and reduces space charge effects Phase-Space plots from C. Y. Tan

7. Real and Model Cavity Cross-Section 8/04/2015Maggie Lankford |7 Cavity Designs Courtesy of Gennady Romanov and Kevin Dule

8. Ferrite Permeability Study 8/04/2015Maggie Lankford |8 Ferrite-Filled Cavity Plug Measured: Q-value, Resonant Frequency Tuning parameter Lossy component Function of frequency and cavity dimensions Solenoid

9. Calculating permeability 8/04/2015Maggie Lankford |9 Real mu’’ experiment and calculations by Yuri Terechkine and Gennady Romanov 106 MHz 76 MHz

10. Poisson Superfish Models Investigating –Change in dimensions –Fundamental frequency –Change in µ –Difference between Real and Model 8/04/2015Maggie Lankford |10 Real Cavity 438.89 MHz 5/4 λ Resonance

11. Difference between Real and Model cavity 8/04/2015Maggie Lankford |11

12. Power Amplifier Basics 8/04/2015Maggie Lankford |12 Center Conductor Blocking Capacitor Assembly Shroud & Corona Ring Tube Test Resonator PA Power Module Existing 53 MHz Power Amplifier76 MHz Power Amplifier Design 50 Ohm Load Difference is in load position and resonator shape PA Power Module Test Resonator

13. Power Dissipation to Temperature 8/04/2015Maggie Lankford |13 https://xkcd.com/643/ T: Temperature Q: Heat Added m: Mass c: Specific Heat

14. Current State of Electronics RTD probe readout electronics complete Troubleshooting complete 8/04/2015Maggie Lankford |14 http://www.rfcafe.com/references/radio-electronics/comics- january-1958-radio-electronics.htm

15. Conclusions Comparison study of real and model cavity with Superfish Permeability study of the ferrite 8/04/2015Maggie Lankford |15 Power Amplifier RTD electronics complete http://www.fnal.gov/pub/today/archive/archive_ 2014/today14-07-31.html

16. Future Work Assembly of physical model cavity 76 MHz Power Amplifier testing Study higher order modes in the model cavity 8/04/2015Maggie Lankford |16 http://cerncourier.com/cws/article/cer n/55333

17. Acknowledgments Robyn Madrak Plant for her endless help and mentoring C. Y. Tan for giving project motivation and background The RF Group for their help with the PA electronics Dave Peterson for his feedback on the presentation The SIST committee for the opportunity to intern at Fermilab 8/04/2015Maggie Lankford |17 https://rootsrated.com/chicago- il/cycling/fermilab-cycling