P rinted O ptical P article S pectrometer A small, sensitive, light-weight, and disposable aerosol spectrometer for balloon and UAV applications Hagen Telg Cooperative Institute for Research in Environmental Sciences NOAA Earth System Research Laboratory May 20, 2014
start motivation how POPS works how POPS performs field test fine Motivation Why aerosols ⇒ large uncertainty about effect on radiative forcing Scientific questions that are difficult to address with existing tools • Aerosol profiles inside the Asian Monsoon → no aircraft excess • Fire plume sampling → no aircraft excess • Volcanic aerosol and ash quantification → no aircraft excess, monitoring needed • Geo-engineering → monitoring needed IPCC: Summary for Policymakers. In: Climate ⇒ A small, light-weight, low cost, low power opti- Change 2013 :The Physical Science Basis cal particle counter will help greatly
start motivation how POPS works how POPS performs field test fine Motivation Why aerosols ⇒ large uncertainty about effect on radiative forcing Scientific questions that are difficult to address with existing tools • Aerosol profiles inside the Asian Monsoon → no aircraft excess • Fire plume sampling → no aircraft excess • Volcanic aerosol and ash quantification → no aircraft excess, monitoring needed • Geo-engineering → monitoring needed ⇒ A small, light-weight, low cost, low power opti- cal particle counter will help greatly
start motivation how POPS works how POPS performs field test fine Motivation UAV Why aerosols ⇒ large uncertainty about effect on radiative forcing Scientific questions that are difficult to address with existing tools weather balloon • Aerosol profiles inside the Asian Monsoon → no aircraft excess • Fire plume sampling → no aircraft excess • Volcanic aerosol and ash quantification → no aircraft excess, monitoring needed • Geo-engineering → monitoring needed ⇒ A small, light-weight, low cost, low power opti- cal particle counter will help greatly
start motivation how POPS works how POPS performs field test fine Motivation Why aerosols ⇒ large uncertainty about effect on radiative forcing Scientific questions that are difficult to address with existing tools • Aerosol profiles inside the Asian Monsoon → no aircraft excess • Fire plume sampling → no aircraft excess • Volcanic aerosol and ash quantification → no aircraft excess, monitoring needed • Geo-engineering → monitoring needed ⇒ A small, light-weight, low cost, low power opti- cal particle counter will help greatly ⇒ P rinted O ptical P article S pectrometer
start motivation how POPS works how POPS performs field test fine How POPS works light-source 405 nm laser diode beam shaping aspherical, and cylindrical lenses shape laser to line light collection spherical mirror image scattered light on P hoto m ultiplier T ube stray light multiple slits suppress stray light signal processing PMT output current converted to voltage → amplified → digitized (4 MHz; 16 bit) → analyzed on single-board computer → communicate via serial port sizing intensity of scattered light depends on particle size R. S. Gao et al. , Aerosol Sci. Technol. 2013 , 47, 137
start motivation how POPS works how POPS performs field test fine How POPS works light-source 405 nm laser diode beam shaping aspherical, and cylindrical lenses shape laser to line light collection spherical mirror image scattered light on P hoto m ultiplier T ube stray light multiple slits suppress stray light signal processing PMT output current converted to voltage → amplified → digitized (4 MHz; 16 bit) → analyzed on single-board computer → communicate via serial port sizing intensity of scattered light depends on particle size R. S. Gao et al. , Aerosol Sci. Technol. 2013 , 47, 137
start motivation how POPS works how POPS performs field test fine How POPS works light-source 405 nm laser diode beam shaping aspherical, and cylindrical lenses shape laser to line light collection spherical mirror image scattered light on P hoto m ultiplier T ube stray light multiple slits suppress stray light signal processing PMT output current converted to voltage → amplified → digitized (4 MHz; 16 bit) → analyzed on single-board computer → communicate via serial port sizing intensity of scattered light depends on particle size R. S. Gao et al. , Aerosol Sci. Technol. 2013 , 47, 137
start motivation how POPS works how POPS performs field test fine How POPS works Mie scattering simulation light-source 405 nm laser diode beam shaping aspherical, and cylindrical lenses shape Scattering efficiency (arb. u.) laser to line light collection spherical mirror image scattered light on P hoto m ultiplier T ube stray light multiple slits suppress stray light signal processing PMT output current converted to voltage → amplified → digitized (4 MHz; 16 bit) → 10 2 10 3 analyzed on Particle diameter (nm) single-board computer → communicate via serial port sizing intensity of scattered light depends on particle size R. S. Gao et al. , Aerosol Sci. Technol. 2013 , 47, 137
start motivation how POPS works how POPS performs field test fine How POPS works POPS versus UHSAS light-source 405 nm laser diode beam shaping aspherical, and cylindrical lenses shape laser to line light collection spherical mirror image scattered light on P hoto m ultiplier T ube stray light multiple slits suppress stray light signal processing PMT output current converted to voltage → amplified → digitized (4 MHz; 16 bit) → analyzed on single-board computer dimensions 15x6x6 cm → communicate via weight < 1 kg serial port cost ∗ ∼ 2500 $ sizing intensity of scattered power 3 W light depends on particle ∗ labor excluded size R. S. Gao et al. , Aerosol Sci. Technol. 2013 , 47, 137
start motivation how POPS works how POPS performs field test fine how POPS performs raw data • single particles are resolved Diameter (nm) • good diameter resolution 180 Signal intensity (arb. u.) ∆ d / d ≈ 15 % • minimum measurable diameter < 150 nm • agreement with theory • comparison to UHSAS shows good agreement in absolute counts (down to 190 nm) Time (arb. u.)
start motivation how POPS works how POPS performs field test fine how POPS performs raw data • single particles are resolved Diameter (nm) • good diameter resolution 180 Signal intensity (arb. u.) ∆ d / d ≈ 15 % • minimum measurable diameter < 150 nm • agreement with theory • comparison to UHSAS shows good agreement in absolute counts (down to 190 nm) Time (arb. u.) peak height histogram Normalized No. of particles per bin 0.10 diameter (nm) 180 0.08 0.06 0.04 0.02 0.00 5 10 15 20 25 30 35 Intensity (digitizer bins)
start motivation how POPS works how POPS performs field test fine how POPS performs raw data • single particles are resolved Diameter (nm) • good diameter resolution 180 Signal intensity (arb. u.) ∆ d / d ≈ 15 % • minimum measurable diameter < 150 nm • agreement with theory • comparison to UHSAS shows good agreement in absolute counts (down to 190 nm) Time (arb. u.) peak height histogram Normalized No. of particles per bin 0.16 diameter (nm) 0.14 150 0.12 160 170 0.10 180 0.08 0.06 0.04 0.02 0.00 5 10 15 20 25 30 35 Intensity (digitizer bins)
start motivation how POPS works how POPS performs field test fine how POPS performs raw data • single particles are resolved Diameter (nm) • good diameter resolution 180 Signal intensity (arb. u.) ∆ d / d ≈ 15 % • minimum measurable diameter < 150 nm • agreement with theory • comparison to UHSAS shows good agreement in absolute counts (down to 190 nm) Time (arb. u.) peak height histogram exp. versus theo. Normalized No. of particles per bin 0.16 Scattered light intensity (arb. u.) exp. diameter (nm) 25 0.14 theo. 150 0.12 160 170 20 0.10 180 0.08 0.06 15 0.04 0.02 10 0.00 5 10 15 20 25 30 35 150 155 160 165 170 175 180 Intensity (digitizer bins) Particle diameter (nm)
start motivation how POPS works how POPS performs field test fine how POPS performs POPS versus UHSAS @ room air • single particles are resolved 9 UHSAS 3 8 • good diameter resolution Number concentration/cm POPS 7 ∆ d / d ≈ 15 % 6 • minimum measurable diameter 5 < 150 nm 4 • agreement with theory 3 2 • comparison to UHSAS shows good 1 agreement in absolute counts (down to 0 190 nm) 100 200 300 400 500600 Diameter (nm)
start motivation how POPS works how POPS performs field test fine field test on Manta UAV Manta & launcher package • POPS • C ondensation N uclei C ounter • 3 wavelengths aerosol absorption ahotometer → like CLAP • aerosol filter sampler → 6 filters • Radiometer Manta pallet CNC Absorption Photometer outcome • POPS functional Radio- but interference with UAV communication meter and other instruments → bursts of noise ⇒ improve shielding POPS Filter Sampler
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