Transcript Huang Stacey sol 2014 sm

Developing Environmental Trace
Gas Sensors based on QuartzEnhanced Photoacoustic
Spectroscopy (QEPAS)
Stacey Huang
October 3, 2014
SOL Colloquim
TU Clausthal
Laser Application Center
Goslar, Germany
Image credit: http://www.lac.tuclausthal.de/fileadmin/_temp_/lac.jpg
 Objectives: develop laser technology for sensors and
material processing
 Current research projects: security applications (detection
of improvised explosives, landmines), chip-based sensors,
temperature sensors for process control, broad energy
research
 Work with industry partners to produce quality sensors
Summer Internship Goals
 To assist in building sensors and instrumentation for
practical use in trace gas sensing
 To gain a broader understanding of different approaches
of laser-based sensors
 To gain insight into the development and troubleshooting
process of sensors industrial
 Skills: experience with lab software, installation of sensor
components (LEDs, tuning forks), handling of optics
(alignment, laser characterization, handling lenses, etc.)
What is Quartz-Enhanced
Photoacoustic Spectroscopy?
 Tuning fork placed in target gas
 Laser focused through tuning fork
 Laser is modulated; i.e., intensity that
the gas observes is changing
 Gas heats and cools at the modulation
frequency, producing pressure
changes
 Quartz tuning fork picks up the
pressure changes as electrical signals
 Signal can be analyzed and used to
determine how much gas is present
Laser beam being focused
through a quartz tuning fork.
(Image credit: http://www.lac.tuclausthal.de/uploads/pics/e6f892c
b11.jpg)
Key Points for Development
 Many associated electronics can be simplified and
compacted into smaller circuits
 Example: laser modulation
 Normally done by various pieces of software and
instrumentation
 For certain types of gas, LEDs can be used instead of lasers
 Lower power draw
 Safer
Summary of work
 Calibration of laser for methane sensor
 Assessment of optimum LED for use in ozone detection
 Development and test of circuits for use in tandem with
the quart tuning fork for a nitric oxide sensor
Afterthoughts
 Contribution in developing trace gas sensors
 Valuable skills: problem-solving, working efficiently,
theoretical knowledge to reality
 Hands-on as well as theoretical knowledge
 Learning to interact with international colleagues in
a foreign environment
 Future prospects: continuing work in electronics
and laser spectroscopy at Princeton
Acknowledgements
 Michael Köhring
 Mario Mordmüller
 Tassilo Söldner
Thank you for your attention!
Questions?