Plasma E- Measurement

1. Plasma E- Measurement Brian DeHerrera John Purcell JaberAssiri

2. Introduction • Purpose • Problems • HFSS Simulation • Current Design • Voltage Divider • Future Work & budget • Conclusion Outline

3. Create reliable current and voltage sensing equipment to work in common plasma ranges • >500V • >10MHz • Create more reliable plasma for experiments • Control line impedance • Measure waveform being transmitted to plasma probe Purpose

4. Plasma System

5. No commercially available probes • Can meet some specifications, but not both frequency and desired voltage • Not trivial to create homebrew probe • Needs to be high impedance • Parasitic Problems

8. Draw Model • Assign Boundary Conditions • Assign Excitation Ports (inputs) • Analyze • Generate Reports HFSS Simulation

9. Draw Model

10. Freq Response

12. Modeled design off of AE’s Z-Scan Benefits: • Parasitic are minimized • Sensor can be added in-line with plasma system Concerns: • EMI design: both shielding outside noise and reducing leakage • Semi-complicated design • Need to machine parts Current Design: Coax

13. Current Design: Coax

14. Current Design: Coax

15. Why a V-D? Voltage Divider

16. Conditions: • R1+R2>= 2M Ohm & C1+C2<10p F Voltage Divider

17. Conditions: • R1*C1=R2*C2 • If (R1*C1)> (R2* C2) Voltage Divider

18. Conditions: • R1*C1=R2*C2 • If (R1*C1)<(R2* C2) Voltage Divider

19. Conditions: • R1*C1=R2*C2 Voltage Divider

20. From: • R1+R2>= 2M Ohm & C1+C2<10pF & • R1*C1=R2*C2 • Therefore: • R1= 10M ohm, R2= 100k ohm • C1= .1pF , C2= 10pF Voltage Divider

21. Future Work

22. Purposes & problems • HFSS Simulation • Current Design • Voltage Divider • Future Work & budget Conclusion

23. Questions ?? Thank you