Universidad de Córdoba

1. Universidad de Córdoba Preliminary experimental results on the QL-lamp fed by 2.45 GHz microwave power Antonio Gamero Department of Physics, University of Cordoba, Spain.

2. UNIVERSIDAD DE CÓRDOBA University of Granada (Spain) M. Rubiño, Y. Yebra and M.M. Pérez Eindhoven University of Technology (Netherlands) J.J.A.M. van der Mullen LPGIP. Université Paris-Sud (Orsay, France) C. Boisse-Laporte Contents - Studies of HF discharges at the University of Cordoba - HF Discharges as Light Sources. Microwave-fed QL-lamp Spectroscopic measurements Radiometric measurements Surface wave in coaxial structure Conclusion / Future

3. UNIVERSIDAD DE CÓRDOBA Departamento de Física Group of HF Discharges : Dr. Carlos Lao Dr. M. Carmen Quintero Dr. Antonio Rodero Dr. Antonio Sola Dr. Antonio Gamero Ph. Students: Olga Carabaño Manuel Fernández José Mª Palomares Sebastián Rubio Jesús Torres

4. UNIVERSIDAD DE CÓRDOBA Departamento de Física Group of HF Discharges : • Surface Wave Discharges (SWDs) • Plasma Torches • - Coaxial Discharges • Spectroscopic Diagnostics • Excitation Source for Spectrochemical Analysis • Destruction of Volatile Organic Compounds (VOCs) • - HF Discharges as Light Sources

5. POWER GENERATOR stubs P ref Power meter P inc plasma manometer gas pump z = 0 waveguide dielectric tube Surfatron Surfacewave Discharges Microwave frequency: 2.45 GHz Microwave power: up to 200 W (1500 W) Gas: Ar, He Pressure: mTorr – 1 atm

6. flame z=10-12 mm noozle WR-340 waveguide tuneable coaxial plunger f= 2.45 GHz gas Microwave Plasma Produced by the Axial Injection Torch (TIA) TIA (Torch á Injection Axiale) Characteristics Microwave power range: 200-3000 W Length: 10-12 mm Diameter: 1 - 2 mm Gas flow rate range: 0.5-15 L min-1

7. Spectroscopic Diagnostics • - Atomic Emission Spectroscopy • Molecular Emission Spectroscopy • Atomic State Distribution Function (ASDF) Departure from LTE

8. Computer Microwave Generator Plasma torch Reactor Gas Chromatograph 0,5% TCE 99,5% He He Destruction of Volatile OrganicCompounds (VOCs) by using microwave plasmaproduced by the Axial Injection Torch (TIA) Reactor TCE = trichloroethylene Destruction and Removal Efficiency (DRE ) > 99.999 %

9. HF Discharges as Light Sources. Microwave-fed QL-lamp (low-pressure argon, 2.45 GHz) The QL-lampfrom Philips, at 2.65 MHz (commercialized since 1992) Experimental version : Argon filled pressure: 66, 133 Pa. Amalgam: Bi/In/Hg in a mass ratio of 68/29/3 Acknowledgment to Dr Wim Hellebrekers (Philips Lighting)

10. Experimental Set-up cavity microwave antenna auxiliary amalgam mercury amalgam Measure point: 4 mm from the inner tube 45 mm below the antenna end QL-lamp at 2.45 GHZ Experimental version : Argon filled pressure: 133 Pa. Amalgam: Bi/In/Hg in a mass ratio of 68/29/3

11. Optic fibre QL-lamp CCD Camera Entrance slit Photomultiplier Monochromator Ribbon lamp Spectroscopic Experimental Set-up

12. Hg Ar effective quantum number Atomic State Distribution Function

13. Atomic State Distribution Function Ar Hg - Excitation Saturation Balance (ESB) x  5 ionisation processes neglected x = 5

14. Radiometric Experimental Set-up

15. Results

16. □ RF (80 W) ■μW (90 W) ■μW (60 W) ■ μW (40 W) ■μW (20 W) Results

17. 1400 20 W 2 40 W 1200 60 W 90 W 1000 800 Spectral radiance (watt/sr·m ) 600 400 200 0 400 500 600 700 800 l (nm) Results

18. 7 ) m 2 W (40 W) 6 RF (80 W) 5 4 Spectral radiance(watt/sr·m 3 2 1 0 400 500 600 700 800 l (nm) Results

19. Results

20. Discharge Inner Conductor Dielectric Tubes Coaxial Discharge

21. Plasma ep Dielectric tube ev = 3.8 Metallic guide Air e= 1 Antenna SurfaceWave Discharges Coaxial structure Antenna R0 = 1.5 mm Inner tube R1 = 4.25 mm R2 = 5.00 mm Outer tube R3 = 11.50 mm R4 = 12.25 mm Guide R5 = 40.00 mm

22. mode I mode II _____ 1/1 + v Surface Wave Propagation - Radially uniform plasma -    Two solutions Azimuthally symmetric modes Er , Ez , H

23. ne Radial profile of the electric field Mode I - Outside Er > Ez - Inside Er < Ez Minimum electric field exists going to the internal tube with the ne - Ein < Eext

24. ne Radial profile of the electric field Mode II - Outside Er > Ez - Inside Er < Ez Minimum electric field exists going to the external tube with the ne - Ein~ Eext

25. Conclusions / Future • It has been possible to produce a stable microwave QL-lamp at 2.45 GHz at the pressure of 1 Torr. • The microwave coupler must be improved in order to optimise the power absorbed by the plasma and so the efficiency of the lamp. • The relative importance of the both possible modes of the surface wave must be experimentally investigated under different experimental conditions. • The propagation of the surface wave in coaxial structure must be solved for different geometric dimension and for plasmas radially no uniform, looking for the best conditions of operation. • New experimental measurements must be made under these new conditions.

26. Universidad de Córdoba Thank you for your attention Antonio Gamero Department of Physics, University of Cordoba, Spain.

28. Ar lines Lines measured Hg lines

29. COST ACTION 529 “Efficient Lighting for the 21th century” Workshop “Radiometric, photometric and color measurements of light sources and applications” Meeting in Granada (Spain), September 22-23, 2005 “Radiometric (and spectroscopic) measurements on a low-pressure argon QL-lamp fed by 2.45 GHz microwaves” by O. Carabaño, M. Fernández, A. Gamero and A. Sola, University of Cordoba (Spain) M Rubiño, Y. Yebra and M.M. Pérez, University of Granada (Spain) J.J.A.M. van der Mullen, University of Eindhoven (Netherlands)