http://bjm.scs.uiuc.edu 23 June 2009
Performance of a Continuous Performance of a Continuous Supersonic Expansion Discharge Supersonic Expansion Discharge
Source Evaluated by Laser-Induced Source Evaluated by Laser-Induced Fluorescence SpectroscopyFluorescence Spectroscopy
Kyle N. Crabtree, Carrie A. Kauffman, and Benjamin J. McCall
23 June 2009McCall Research Group
University of Illinoishttp://bjm.scs.uiuc.edu
http://bjm.scs.uiuc.edu 23 June 2009
OverviewOverview
Intro/Motivation Experimental Layout Spectroscopic Efforts Current Measurements
http://bjm.scs.uiuc.edu 23 June 2009
Supersonic Expansion Supersonic Expansion Discharge SourceDischarge Source
Operational lifetime: >100 hrs
Typical Voltage: 200-500 V
Typical Current: ~30 mA
Typical Pressure: 1-3 atm
http://bjm.scs.uiuc.edu 23 June 2009
Source OptimizationSource Optimization
Pressure Composition Diameters Lengths Diameter Ratio Voltage/Current Polarity Size Geometry Material Size Geometry
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LIF SpectroscopyLIF Spectroscopy
Generate 2D map of ion temperature and relative density
1. Optimize spectrometer using I2
2. Make map using N2+
3. Vary source parameters, and repeat
4. Investigate larger, more complex ions
http://bjm.scs.uiuc.edu 23 June 2009
OverviewOverview
Intro/Motivation Experimental Layout Spectroscopic Efforts Current Measurements
http://bjm.scs.uiuc.edu 23 June 2009
Experimental LayoutExperimental Layout
Nd:YVO4
PMTComputer
Laser Locking/Scanning
Electronics
DAQ
Lock-inAmplifier
899-29Ring Dye Laser
λ-meter
Optical Chopper
I2Cell
High-VoltagePower Supply
N2
I2OpticalFilter(s)
http://bjm.scs.uiuc.edu 23 June 2009
CFN899 AutoscanCFN899 Autoscan
LaserPower
Long & Short Vernier Etalons
Thin Etalon
Scan Drive
I2 CellAbsorption
Vernier Etalons
http://bjm.scs.uiuc.edu 23 June 2009
OverviewOverview
Intro/Motivation Experimental Layout Spectroscopic Efforts Current Measurements
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Molecular IodineMolecular Iodine
B3Π0+
u – X1Σg+ (6-0), (8-1), (10-2), and
(12-3) vibronic transitions at 608 nm
Sample Spectrum Here Boltzmann Plot Here
)
http://bjm.scs.uiuc.edu 23 June 2009
T.A. Miller, T. Suzuki, E. Hirota J. Chem. Phys. 80, (1984) 4671-4678.
NN22++
A2Πu – X2Σg+ (4-0)
Meinel Band transition (614 nm)
LIF characterization by T.A. Miller et al. in 1984
2Π3/22Π1/2
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Source EmissionSource Emission
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OverviewOverview
Intro/Motivation Experimental Layout Spectroscopic Efforts Current Measurements
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Spectroscopy of HSpectroscopy of H33++ ((νν22 0) 0)
(ortho) (para) (para) (ortho)
J
500
0
0 1 2 3
E(c
m-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)
http://bjm.scs.uiuc.edu 23 June 2009
Difference Frequency LaserDifference Frequency LaserMgO-doped PPLN crystalSpectral Coverage: 2.2 – 4.8 μmPower: ~350 μW
11
2
2
http://bjm.scs.uiuc.edu 23 June 2009
Summary/Future DirectionsSummary/Future Directions
Design and construction of source Iodine rotational temperature: 8 K Cavity ringdown spectroscopy of H3
+ with difference frequency laser
Future work: temperature measurements of larger ions
Integration with SCRIBES
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AcknowledgementsAcknowledgements
University of Illinois SCS Machine Shop
Bill Knight Christopher Neese McCall Research
Group
http://bjm.scs.uiuc.edu 23 June 2009
Cavity Ringdown Cavity Ringdown SpectroscopySpectroscopy
