23 June 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

23 June Overview  Intro/Motivation  Experimental Layout  Spectroscopic Efforts  Current Measurements

23 June Supersonic Expansion Discharge Source Operational lifetime: >100 hrs Typical Voltage: V Typical Current: ~30 mA Typical Pressure: 1-3 atm

23 June Source Optimization  Pressure  Composition  Diameters  Lengths  Diameter Ratio  Voltage/Current  Polarity  Size  Geometry  Material  Size  Geometry

23 June LIF Spectroscopy  Generate 2D map of ion temperature and relative density 1. Optimize spectrometer using I 2 2. Make map using N Vary source parameters, and repeat 4. Investigate larger, more complex ions

23 June Overview  Intro/Motivation  Experimental Layout  Spectroscopic Efforts  Current Measurements

23 June Experimental Layout Nd:YVO 4 PMT Computer Laser Locking/ Scanning Electronics DAQ Lock-in Amplifier Ring Dye Laser λ- meter Optical Chopper I 2 Cell High-Voltage Power Supply N2N2 I2I2 Optical Filter(s)

23 June CFN899 Autoscan Laser Power Long & Short Vernier Etalons Thin Etalon Scan Drive I 2 Cell Absorption Vernier Etalons

23 June Overview  Intro/Motivation  Experimental Layout  Spectroscopic Efforts  Current Measurements

23 June 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 )

23 June T.A. Miller, T. Suzuki, E. Hirota J. Chem. Phys. 80, (1984) 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 Π 3/2 2 Π 1/2

23 June Source Emission

23 June Overview  Intro/Motivation  Experimental Layout  Spectroscopic Efforts  Current Measurements

23 June Spectroscopy of H 3 + ( ν 2  0) (ortho) (para) (para) (ortho) J E(cm -1 ) K R(1,0) R(1,1) 64 cm cm cm cm cm -1 R(2,1) R(2,2) R(3,3)

23 June Difference Frequency Laser MgO-doped PPLN crystal Spectral Coverage: 2.2 – 4.8 μ m Power: ~350 μW

23 June 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

23 June Acknowledgements  University of Illinois SCS Machine Shop  Bill Knight  Christopher Neese  McCall Research Group

23 June Cavity Ringdown Spectroscopy