1. 23 June 2009 http://bjm.scs.uiuc.edu Performance of a Continuous Supersonic Expansion Discharge Source Evaluated by Laser-Induced Fluorescence Spectroscopy Kyle N. Crabtree, Carrie A. Kauffman, and Benjamin J. McCall 23 June 2009 McCall Research Group University of Illinois http://bjm.scs.uiuc.edu

2. 23 June 2009 http://bjm.scs.uiuc.edu Overview  Intro/Motivation  Experimental Layout  Spectroscopic Efforts  Current Measurements

3. 23 June 2009 http://bjm.scs.uiuc.edu Supersonic Expansion Discharge Source Operational lifetime: >100 hrs Typical Voltage: 200-500 V Typical Current: ~30 mA Typical Pressure: 1-3 atm

4. 23 June 2009 http://bjm.scs.uiuc.edu Source Optimization  Pressure  Composition  Diameters  Lengths  Diameter Ratio  Voltage/Current  Polarity  Size  Geometry  Material  Size  Geometry

5. 23 June 2009 http://bjm.scs.uiuc.edu LIF Spectroscopy  Generate 2D map of ion temperature and relative density 1. Optimize spectrometer using I 2 2. Make map using N 2 + 3. Vary source parameters, and repeat 4. Investigate larger, more complex ions

6. 23 June 2009 http://bjm.scs.uiuc.edu Overview  Intro/Motivation  Experimental Layout  Spectroscopic Efforts  Current Measurements

7. 23 June 2009 http://bjm.scs.uiuc.edu Experimental Layout Nd:YVO 4 PMT Computer Laser Locking/ Scanning Electronics DAQ Lock-in Amplifier 899-29 Ring Dye Laser λ- meter Optical Chopper I 2 Cell High-Voltage Power Supply N2N2 I2I2 Optical Filter(s)

8. 23 June 2009 http://bjm.scs.uiuc.edu CFN899 Autoscan Laser Power Long & Short Vernier Etalons Thin Etalon Scan Drive I 2 Cell Absorption Vernier Etalons

9. 23 June 2009 http://bjm.scs.uiuc.edu Overview  Intro/Motivation  Experimental Layout  Spectroscopic Efforts  Current Measurements

10. 23 June 2009 http://bjm.scs.uiuc.edu Molecular Iodine  B 3 Π 0 + u – X 1 Σ g + (6-0), (8-1), (10-2), and (12-3) vibronic transitions at 608 nm Sample Spectrum Here Boltzmann Plot Here )

11. 23 June 2009 http://bjm.scs.uiuc.edu T.A. Miller, T. Suzuki, E. Hirota J. Chem. Phys. 80, (1984) 4671-4678. N2+N2+N2+N2+  A 2 Π u – X 2 Σ g + (4-0) Meinel Band transition (614 nm)  LIF characterization by T.A. Miller et al. in 1984 2 Π 3/2 2 Π 1/2

12. 23 June 2009 http://bjm.scs.uiuc.edu Source Emission

13. 23 June 2009 http://bjm.scs.uiuc.edu Overview  Intro/Motivation  Experimental Layout  Spectroscopic Efforts  Current Measurements

14. 23 June 2009 http://bjm.scs.uiuc.edu Spectroscopy of H 3 + ( ν 2  0) (ortho) (para) (para) (ortho) J 500 0 0123 E(cm -1 ) K 3 2 1 0 R(1,0) R(1,1) 64 cm -1 169 cm -1 315 cm -1 237 cm -1 87 cm -1 R(2,1) R(2,2) R(3,3)

15. 23 June 2009 http://bjm.scs.uiuc.edu Difference Frequency Laser MgO-doped PPLN crystal Spectral Coverage: 2.2 – 4.8 μ m Power: ~350 μW 1 1 2 2

16. 23 June 2009 http://bjm.scs.uiuc.edu Summary/Future Directions  Design and construction of source  Iodine rotational temperature: 8 K  Cavity ringdown spectroscopy of H 3 + with difference frequency laser  Future work: temperature measurements of larger ions  Integration with SCRIBES

17. 23 June 2009 http://bjm.scs.uiuc.edu Acknowledgements  University of Illinois SCS Machine Shop  Bill Knight  Christopher Neese  McCall Research Group

18. 23 June 2009 http://bjm.scs.uiuc.edu Cavity Ringdown Spectroscopy