Submillimeter wave spectrometry for in-situ planetary science

Drouin, Brian J.; Cooper, Ken B.; Dengler, Robert J.; Chavez, M. C.; Chun, W.; Crawford, Tim

doi:10.1109/aero.2012.6187067

Cited by 4 publications

(4 citation statements)

References 8 publications

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“…The center frequencies of the lines we observe agree with catalog values, 22,25 and we do not observe significant pressure or transit time broadening compared to what we have previously observed for stable gases, 4,5 which implies that the ablation products collide with the carrier gas and then expand together with it. Previous articles 4,5,18,30 discussed the small size and low power consumption of the FTmmW instrument and how it could be used to measure volatiles or stable atmospheric species in situ. 30,31 Our FTmmW detections of laser-volatilized NaCl and KCl demonstrate that the instrument can also be used to determine the molecular composition of condensed phases.…”

Section: ■ Discussionmentioning

confidence: 99%

“…Previous articles 4,5,18,30 discussed the small size and low power consumption of the FTmmW instrument and how it could be used to measure volatiles or stable atmospheric species in situ. 30,31 Our FTmmW detections of laser-volatilized NaCl and KCl demonstrate that the instrument can also be used to determine the molecular composition of condensed phases. Such a capability is complementary to mass spectrometry techniques, which are sensitive to ions, not neutral species.…”

Section: ■ Discussionmentioning

confidence: 99%

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Detecting Laser-Volatilized Salts with a Miniature 100-GHz Spectrometer

et al. 2020

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Rotational transitions are unique identifiers of molecular species, including isotopologues. This article describes the rotational detections of two laser-volatilized salts, NaCl and KCl, made with a miniature Fourier transform millimeter-wave (FTmmW) cavity spectrometer that could one day be used to measure solid composition in the field or in space. The two salts are relevant targets for icy moons in the outer solar system, and in principle, other molecular solids could be analyzed with the FTmmW instrument. By coupling the spectrometer to a collisionally cooling laser ablation source, (a) we demonstrate that the FTmmW instrument is sensitive enough to detect ablation products, and (b) we use the small size of the FTmmW cavity to measure ablation product signal along the carrier gas beam. We find that for 532 nm nanosecond pulses, ablated molecules are widely dispersed in the carrier-gas jet. In addition to the miniature spectrometer results, we present several complementary measurements intended to characterize the laser ablation process. For pulse energies between 10 and 30 mJ, the ablation product yield increases linearly, reaching approximately 1012 salt molecules per 30 mJ pulse. Using mass spectrometry, we observe Li+, Na+, and K+ in the plumes of ablated NaCl, KCl, and LiCl, which implies dissociation of the volatilized material. We do not observe salt ions (e.g., NaCl+). However, with 800 nm femtosecond laser pulses, the triatomic ion clusters Li2Cl+, Na2Cl+, and K2Cl+ are produced. Finally, we observe incomplete volatilization with the nanosecond pulses: some of the ejecta are liquid droplets. The insights about ablation plume physics gleaned from these experiments should guide future implementations of the laser-volatilization technique.

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Section: ■ Discussionmentioning

confidence: 99%

Section: ■ Discussionmentioning

confidence: 99%

Detecting Laser-Volatilized Salts with a Miniature 100-GHz Spectrometer

et al. 2020

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“…Recognizing the intrinsic sensitivity to gases with permanent dipole moments, we have pursued development of deployable systems capable of rotational spectrum sensing (Drouin et al 2016;Raymond et al 2017;Nemchick et al 2018a;Raymond et al 2020). Other efforts, including developments at Ohio and Wright State Universities (Medvedev et al 2010;Lou et al 2019), our laboratory (Drouin et al 2012), and Dunkerque (Hindle et al 2019;Elmaleh et al 2023) where highly sensitive quantitative sensors at millimeter and submillimeter wavelengths utilizing absorption techniques, have been demonstrated. These methods are sensitive; however, the apparatus tend to be difficult to miniaturize, and the measurement time must be traded for frequency scanning to trace out an absorption feature.…”

Section: Scientific and Measurement Backgroundmentioning

confidence: 99%

Dual-band Fourier-transform Millimeter-wave Spectrometry for In Situ Gas Sensing

et al. 2023

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The exploration of icy body composition in the solar system has often involved spectroscopic measurements of volatiles detected with remote sensing, such measurements portray materials naturally expelled from the surface that enter the exosphere and potentially escape into space. Variations in the ratio of deuterium and hydrogen in these measurements have led to inconclusive hypotheses regarding potential cometary origins of Earth’s ocean water and/or organics. Observational biases regarding unknown previous processing of the observable ejected materials necessitates studies of more dormant, less-processed bodies. Landed missions on comets have brought focus onto the development of small, sensitive instrumentation capable of similar composition measurements of the nascent surface and near-surface materials. We present an evolution of our compact Fourier-transform millimeter-wave cavity spectrometer that is tuned for sensitivity at 80.6 and 183 GHz where HDO and H2O exhibit resonance features. We discuss both a low-SWaP (size–weight and power) architecture that uses custom microchip transceiver elements as well as a modular configuration using traditional GaAs-based millimeter-wave hardware. New design features for these systems including quartz-based coupling elements, system thermal management, and a separable clocking board are discussed in addition to sensitivity studies and applications in potential mission scenarios.

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“…With the development of multiplier based electronic sources came also concurrent development of THz transceivers [110], [111]. For application on earth, millimeter-wavelengths provide for significant propagation distances in the moist atmosphere.…”

Section: E Thz Radarmentioning

confidence: 99%

Instrumentation for THz Spectroscopy in the Laboratory and in Space

Pearson

Drouin

2021

IEEE J. Microw.

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Spectroscopic measurements in the millimeter, submillimeter, or THz range, with resolutions exceeding a MHz, provide for highly specific detections of gas-phase absorption and emission by atoms and molecules. Due to relatively low excitation energies involved in the transitions, multiple features are observable in most physical systems, and thus such observations dominate the scientific discovery of molecules in space and contribute significantly to remote sensing of the Earth and planetary bodies. The methods and techniques of THz spectroscopy continue to evolve as capabilities and technologies expand. In this article, we review the genesis of THz spectroscopy in both the laboratory and in space, and follow its development to date, providing background on the challenges, and context for the current developments that promise to extend both remote and in-situ gas composition sensing.

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Submillimeter wave spectrometry for in-situ planetary science

Cited by 4 publications

References 8 publications

Detecting Laser-Volatilized Salts with a Miniature 100-GHz Spectrometer

Detecting Laser-Volatilized Salts with a Miniature 100-GHz Spectrometer

Dual-band Fourier-transform Millimeter-wave Spectrometry for In Situ Gas Sensing

Instrumentation for THz Spectroscopy in the Laboratory and in Space

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