Molecular Beam Mass Spectrometry for Analysis of ... - EVUR
Molecular Beam Mass Spectrometry for Analysis of ... - EVUR
Molecular Beam Mass Spectrometry for Analysis of ... - EVUR
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Diode laser spectroscopy<br />
Ramp<br />
generator<br />
oscilloscope<br />
DFB-DL<br />
BD<br />
NATIONAL RENEWABLE ENERGY LABORATORY<br />
Herriott cell<br />
Photograph showing Herriott cell (top) and schematic <strong>of</strong> diode<br />
laser spectrometer. BD – balanced detector, DFB-DL – distributed<br />
feedback diode laser<br />
•Based on near-IR absorption spectroscopy<br />
• Detection limit: 0.1 ppmv<br />
•Response time ~ 2 sec<br />
•Expandable to multispecies detection at<br />
roughly $5000/component<br />
Limitations:<br />
•Susceptible to absorption interferences,<br />
especially water vapor<br />
•High resolution spectroscopy unknown <strong>for</strong><br />
most species<br />
Multipass pattern<br />
observed on 2” mirror<br />
using 660 nm alignment<br />
laser. Effective pathlength<br />
~ 49 meters.<br />
Contact: David Robichaud (david.robichaud@nrel.gov)<br />
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