Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Miniature Plasma Sources for High-Precision Molecular Spectroscopy in Planetary Exploration
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). (Ångström Space Technology Centre (ÅSTC))ORCID iD: 0000-0003-0832-1848
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The prospect of finding life outside Earth has fascinated mankind for ages, and new technology continuously pushes the boundary of how remote and how obscure evidence we can find. Employing smaller, or completely new, types of landers and robots, and equipping them with miniature instruments would indeed revolutionize exploration of other planets and moons.

In this thesis, microsystems technology is used to create a miniature high-precision isotope-resolving molecular spectrometer utilizing the optogalvanic effect. The heart of the instrument, as well as this thesis, is a microplasma source.

The plasma source is a split-ring resonator, chosen for its simplicity, pressure range and easily accessible plasma, and modified to fit the challenging application, e.g., by the adding of an additional ground plane for improved electromagnetic shielding, and the integration of microscopic plasma probes to extract the pristine optogalvanic signal.

Plasma sources of this kind have been manufactured in both printed circuit board and alumina, the latter for its chemical inertness and for compatibility with other devices in a total analysis system. From previous studies, classical optogalvanic spectroscopy (OGS), although being very sensitive, is known to suffer from stability and reproducibility issues. In this thesis several studies were conducted to investigate and improve these shortcomings, and to improve the signal-to-noise ratio. Moreover, extensive work was put into understanding the underlying physics of the technique.

The plasma sources developed here, are the first ever miniature devices to be used in OGS, and exhibits several benefits compared to traditional solutions. Furthermore, it has been confirmed that OGS scales well with miniaturization. For example, the signal strength does not decrease as the volume is reduced like in regular absorption spectroscopy. Moreover, the stability and reproducibility are greatly increased, in some cases as much as by two orders of magnitude, compared with recent studies made on a classical OGS setup. The signal-to-noise ratio has also been greatly improved, e.g., by enclosing the sample cell and by biasing the plasma. Another benefit of a miniature sample cell is the miniscule amount of sample it requires, which can be important in many applications where only small amounts of sample are available.

To conclude: With this work, an important step toward a miniature, yet highly performing, instrument for detection of extraterrestrial life, has been taken.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2015. , 53 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1253
Keyword [en]
MEMS, MST, Optogalvanic Spectroscopy, Molecular Spectroscopy, Split-Ring Resonator, Microplasma
National Category
Physical Sciences Engineering and Technology
Research subject
Engineering Science with specialization in Microsystems Technology
Identifiers
URN: urn:nbn:se:uu:diva-251315ISBN: 978-91-554-9245-8 (print)OAI: oai:DiVA.org:uu-251315DiVA: diva2:805359
Public defence
2015-06-05, Polhemsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Opponent
Supervisors
Available from: 2015-05-11 Created: 2015-04-15 Last updated: 2015-07-07
List of papers
1. Operation characteristics and optical emission distribution of a miniaturized silicon through-substrate split-ring resonator microplasma source
Open this publication in new window or tab >>Operation characteristics and optical emission distribution of a miniaturized silicon through-substrate split-ring resonator microplasma source
2014 (English)In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 23, no 6, 1340-1345 p.Article in journal (Refereed) Published
Abstract [en]

There are many new microplasma sources being developed for a wide variety of applications, each with different properties tailored to its specific use. Microplasma sources enable portable instruments for, e.g., chemical analysis, sterilization, or activation of substances. A novel microplasma source, based on a microstrip split-ring resonator design with electrodes integrated in its silicon substrate, was designed, manufactured, and evaluated. This device has a plasma discharge gap with a controlled volume and geometry, and offers straightforward integration with other microelectromechancial systems (MEMS) components, e.g., microfluidics. The realized device was resonant at around 2.9 GHz with a quality factor of 18.7. Two different operational modes were observed with the plasma at high pressure being confined in the gap between the electrodes, whereas the plasma at low pressures appeared between the ends of the electrodes on the backside. Measurement of the angular distribution of light emitted from the device with through-substrate electrodes showed narrow emission lobes compared with a reference plasma source with on-substrate electrodes.

National Category
Physical Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-239111 (URN)10.1109/JMEMS.2014.2312849 (DOI)000345851100010 ()
Available from: 2015-01-05 Created: 2014-12-18 Last updated: 2017-12-05Bibliographically approved
2. Evaluation of a microplasma source based on a stripline split-ring resonator
Open this publication in new window or tab >>Evaluation of a microplasma source based on a stripline split-ring resonator
2013 (English)In: Plasma sources science & technology (Print), ISSN 0963-0252, E-ISSN 1361-6595, Vol. 22, no 5, 055017- p.Article in journal (Refereed) Published
Abstract [en]

In this paper, a stripline split-ring resonator microwave-induced plasma source, aimed for integration in complex systems, is presented and compared with a traditional microstrip design. Devices based on the two designs are evaluated using a plasma breakdown test setup for measuring the power required to ignite plasmas at different pressures. Moreover, the radiation efficiency of the devices is investigated with a Wheeler cap, and their electromagnetic compatibility is investigated in a variable electrical environment emulating an application. Finally, the basic properties of the plasma in the two designs are investigated in terms of electron temperature, plasma potential and ion density. The study shows that, with a minor increase in plasma ignition power, the stripline design provides a more isolated and easy-to-integrate alternative to the conventional microstrip design. Moreover, the stripline devices showed a decreased antenna efficiency as compared with their microstrip counterparts, which is beneficial for plasma sources. Furthermore, the investigated stripline devices exhibited virtually no frequency shift in a varying electromagnetic environment, whereas the resonance frequency of their microstrip counterparts shifted up to 17.5%. With regard to the plasma parameters, the different designs showed only minor differences in electron temperature, whereas the ion density was higher with the stripline design.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2013
Keyword
Split-ring resonator, Microwave plasma, Microstrip, Stripline, Plasma, Wheeler cap, Langmuir probe
National Category
Other Physics Topics Engineering and Technology
Research subject
Engineering Science with specialization in Microsystems Technology; Engineering Science with specialization in Microwave Technology
Identifiers
urn:nbn:se:uu:diva-206792 (URN)10.1088/0963-0252/22/5/055017 (DOI)000325246400017 ()
Available from: 2013-09-04 Created: 2013-09-04 Last updated: 2017-12-06Bibliographically approved
3. Microplasma source for optogalvanic spectroscopy of nanogram samples
Open this publication in new window or tab >>Microplasma source for optogalvanic spectroscopy of nanogram samples
2013 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 114, no 3, 033302- p.Article in journal (Refereed) Published
Abstract [en]

The demand for analysis of smaller samples in isotopic ratio measurements of rare isotopes is continuously rising with the development of new applications, particularly in biomedicine. Interesting in this aspect are methods based on optogalvanic spectroscopy, which have been reported to facilitate both 13C-to-12C and 14C-to-12C ratio measurements with high sensitivity. These methods also facilitate analysis of very small samples, down to the microgram range, which makes them very competitive to other technologies, e.g., accelerator mass spectroscopy. However, there exists a demand for moving beyond the microgram range, especially from regenerative medicine, where samples consist of, e.g., DNA, and, hence, the total sample amount is extremely small. Making optogalvanic spectroscopy of carbon isotopes applicable to such small samples, requires miniaturization of the key component of the system, namely the plasma source, in which the sample is ionized before analysis. In this paper, a novel design of such a microplasma source based on a stripline split-ring resonator is presented and evaluated in a basic optogalvanic spectrometer. The investigations focus on the capability of the plasma source to measure the optogalvanic signal in general, and the effect of different system and device specific parameters on the amplitude and stability of the optogalvanic signal in particular. Different sources of noise and instabilities are identified, and methods of mitigating these issues are discussed. Finally, the ability of the cell to handle analysis of samples down to the nanogram range is investigated, pinpointing the great prospects of stripline split-ring resonators in optogalvanic spectroscopy.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2013
Keyword
nanostructured materials, optogalvanic spectroscopy, plasma instability, plasma probes, plasma sources, strip line resonators
National Category
Other Physics Topics Engineering and Technology
Research subject
Engineering Science with specialization in Microsystems Technology; Engineering Science with specialization in Ion Physics; Engineering Science with specialization in Microwave Technology
Identifiers
urn:nbn:se:uu:diva-204156 (URN)10.1063/1.4813414 (DOI)000322202700014 ()
Available from: 2013-07-22 Created: 2013-07-22 Last updated: 2017-12-06Bibliographically approved
4. Stripline split-ring resonator with integrated optogalvanic sample cell
Open this publication in new window or tab >>Stripline split-ring resonator with integrated optogalvanic sample cell
Show others...
2014 (English)In: Laser Physics Letters, ISSN 1612-2011, Vol. 11, no 4, 045701- p.Article in journal, Letter (Refereed) Published
Abstract [en]

Intracavity optogalvanic spectroscopy (ICOGS) has been proposed as a method for unambiguous detection of rare isotopes. Of particular interest is 14C, where detection of extremely low concentrations in the 1:1015 range (14C:12C), is of interest in, e.g., radiocarbon dating and pharmaceutical sciences. However, recent reports show that ICOGS suffers from substantial problems with reproducibility. To qualify ICOGS as an analytical method, more stable and reliable plasma generation and signal detection are needed. In our proposed setup, critical parameters have been improved. We have utilized a stripline split-ring resonator microwave-induced microplasma source to excite and sustain the plasma. Such a microplasma source offers several advantages over conventional ICOGS plasma sources. For example, the stripline split-ring resonator concept employs separated plasma generation and signal detection, which enables sensitive detection at stable plasma conditions. The concept also permits in situ observation of the discharge conditions, which was found to improve reproducibility. Unique to the stripline split-ring resonator microplasma source of in this study, is that the optogalvanic sample cell has been embedded in the device itself. This integration enabled improved temperature control and more stable and accurate signal detection. Significant improvements are demonstrated, including reproducibility, signal-to-noise ratio and precision.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2014
Keyword
Optogalvanic spectroscopy, Laser-assisted ratio analyzer, Split-ring resonator, microwave-induced microplasma source
National Category
Atom and Molecular Physics and Optics Fusion, Plasma and Space Physics Other Materials Engineering
Research subject
Physics; Engineering Science with specialization in Microsystems Technology
Identifiers
urn:nbn:se:uu:diva-218769 (URN)10.1088/1612-2011/11/4/045701 (DOI)000332768800011 ()
Funder
Swedish Research Council, A0442201
Available from: 2014-02-17 Created: 2014-02-17 Last updated: 2015-05-12Bibliographically approved
5. Improved optogalvanic detection with voltage biased Langmuir probes
Open this publication in new window or tab >>Improved optogalvanic detection with voltage biased Langmuir probes
2014 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 116, no 24, 243301- p.Article in journal (Refereed) Published
Abstract [en]

Optogalvanic detectors show great potential for infrared spectroscopy, especially in cavity enhanced techniques where they, in contrast to ordinary absorption detectors, can perform intracavity measurements. This enables them to utilize the signal-to-noise ratio improvement gained from the extended effective path length inside an optical cavity, without losing signal strength due to the limited amount of light exiting through the rear mirror. However, if optogalvanic detectors are to become truly competitive, their intrinsic sensitivity and stability has to be improved. This, in turn, requires a better understanding of the mechanisms behind the generation of the optogalvanic signal. The study presented here focuses on an optogalvanic detector based on a miniaturized stripline split-ring resonator plasma source equipped with Langmuir probes for detecting the optogalvanic signal. In particular, the effect of applying a constant bias voltage to one of the probes is investigated, both with respect to the sensitivity and stability, and to the mechanism behind the generation of the signal. Experiments with different bias voltages at different pressures and gas composition have been conducted. In particular, two different gas compositions (pure CO2 and 0.25% CO2 in 99.75% N-2) at six different pressures (100 Pa to 600 Pa) have been studied. It has been shown that probe biasing effectively improves the performance of the detector, by increasing the amplitude of the signal linearly over one order of magnitude, and the stability by about 40% compared with previous studies. Furthermore, it has been shown that relatively straightforward plasma theory can be applied to interpret the mechanism behind the generation of the signal, although additional mechanisms, such as rovibrational excitation from electron-molecule collisions, become apparent in CO2 plasmas with electron energies in the 1-6 eV range. With the achieved performance improvement and the more solid theoretical framework presented here, stripline split-ring resonator optogalvanic detectors can evolve into a compact, inexpensive, and easy-to-operate alternative for future infrared spectrometers. (C) 2014 AIP Publishing LLC.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-242865 (URN)10.1063/1.4904964 (DOI)000347164300003 ()
Available from: 2015-02-04 Created: 2015-02-02 Last updated: 2017-12-05Bibliographically approved
6. Evaluation of dielectric properties of HTCC alumina for realization of plasma sources
Open this publication in new window or tab >>Evaluation of dielectric properties of HTCC alumina for realization of plasma sources
2015 (English)In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 44, no 10, 3654-3660 p.Article in journal (Refereed) Published
Abstract [en]

As the sensitivity of optogalvanic spectroscopy based on prototype microplasma sources increases, contamination from composite materials in the printed circuit board used starts to become a concern. In this paper, a transfer to high-temperature cofired alumina and platinum is made and evaluated. The high-purity alumina provides an inert plasma environment, and allows for temperatures above 1000A degrees C, which is beneficial for future integration of a combustor. To facilitate the design of high-end plasma sources, characterization of the radio frequency (RF) parameters of the materials around 2.6 GHz is carried out. A RF resonator structure was fabricated in both microstrip and stripline configurations. These resonators were geometrically and electrically characterized, and epsilon (r) and tan were calculated using the RF waveguide design tool Wcalc. The resulting epsilon (r) for the microstrip and stripline was found to be 10.68 (+/- 0.12) and 9.65 (+/- 0.14), respectively. The average tan of all devices was found to be 0.0011 (+/- 0.0007). With these parameters, a series of proof-of-concept plasma sources were fabricated and evaluated. Some problems in the fabrication stemmed from the lamination and difficulties with the screen-printing, but a functioning plasma source was demonstrated.

National Category
Ceramics Engineering and Technology Physical Sciences
Research subject
Engineering Science with specialization in Microsystems Technology
Identifiers
urn:nbn:se:uu:diva-251300 (URN)10.1007/s11664-015-3901-7 (DOI)000360672900061 ()
Funder
Swedish National Space BoardKnut and Alice Wallenberg Foundation
Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2017-12-04Bibliographically approved
7. Manufacturing Miniature Langmuir probes by Fusing Platinum Bond Wires
Open this publication in new window or tab >>Manufacturing Miniature Langmuir probes by Fusing Platinum Bond Wires
2015 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 10, 105012Article in journal (Refereed) Published
Abstract [en]

This paper reports on a novel method for manufacturing microscopic Langmuir probes with spherical tips from platinum bond wires for plasma characterization in microplasma sources by fusing. Here, the resulting endpoints, formed by droplets of a fused wire, are intended to act as a spherical Langmuir probe. For studying the fusing behavior, bond wires were wedge-bonded over a 2 mm wide slit, to emulate the final application, and fused at different currents and voltages. For electrical isolation, a set of wires were coated with a 4 µm thick layer of Parylene before they were fused. After fusing, the gap size, as well as the shape and area of the ends of the remaining stubs were measured. The yield of the process was also investigated, and the fusing event was studied using a high-speed camera for analyzing the dynamics of fusing. Four characteristic tip shapes were observed: spherical, semi-spherical, serpentine shaped and folded. The stub length leveled out at ~420µm. The fusing of the coated wires required a higher power for attaining a spherical shape. Finally, a Parylene coated bond wire was integrated into a stripline split-ring resonator (SSRR) microplasma source, and fused to form two Langmuir probes with spherical endpoints. These probes were used for measuring the I-V characteristics of a plasma generated by the SSRR. In a voltage range between -60 V and 60 V, the fused stubs exhibited the expected behavior of spherical Langmuir probes and will be considered for future integration.

Keyword
Langmuir probe; bond wire; fusing; microplasma source
National Category
Physical Sciences Engineering and Technology
Research subject
Engineering Science with specialization in Microsystems Technology
Identifiers
urn:nbn:se:uu:diva-251306 (URN)10.1088/0960-1317/25/10/105012 (DOI)000366827400028 ()
Funder
Swedish National Space BoardKnut and Alice Wallenberg Foundation
Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2017-12-04Bibliographically approved

Open Access in DiVA

fulltext(1373 kB)653 downloads
File information
File name FULLTEXT01.pdfFile size 1373 kBChecksum SHA-512
95494e87558fb0d0ae7a215ed739ca4675a543864fae95236eb3ea44dc7f0abf818ee132886a659306a62e0e324801218def3e5d7876b9a0e65fca71b92ecc17
Type fulltextMimetype application/pdf
Buy this publication >>

Search in DiVA

By author/editor
Berglund, Martin
By organisation
Ångström Space Technology Centre (ÅSTC)
Physical SciencesEngineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 653 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 3030 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf