| 1. |
- Berglund, Martin, 1985-, et al.
(författare)
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Manufacturing Miniature Langmuir probes by Fusing Platinum Bond Wires
- 2015
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Ingår i: Journal of Micromechanics and Microengineering. - Bristol : Institute of Physics Publishing (IOPP). - 0960-1317 .- 1361-6439. ; 25:10
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on a novel method for manufacturing microscopic Langmuir probes with spherical tips from platinum bond wires by fusing for plasma characterization in microplasma sources. Here, the resulting endpoints, formed by droplets on the ends of a fused wire, are intended to act as spherical Langmuir probes. For studying the fusing behavior, bond wires were wedge bonded over a 2 mm wide slit, to emulate the final application, and fused with different voltages and currents. 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 its dynamics. Four characteristic tip shapes were observed: spherical, folded, serpentine shaped and semi-spherical. The stub length leveled out at ~400 μm as the fusing power increased. The fusing of the coated wires required a higher power to yield a spherical shape. Finally, a Parylene coated bond wire was integrated into a stripline split-ring resonator (SSRR) microplasma source, and was 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 further integration.
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| 2. |
- Persson, Anders, et al.
(författare)
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Optogalvanic spectroscopy with microplasma sources – Current status and development towards lab on a chip
- 2016
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Ingår i: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 0960-1317 .- 1361-6439. ; 26:10
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Tidskriftsartikel (refereegranskat)abstract
- Miniaturized optogalvanic spectroscopy (OGS) shows excellent prospects of becoming ahighly sensitive method for gas analysis in micro total analysis systems. Here, a status reporton the current development of microwave induced microplasma sources for OGS is presented,together with the first comparison of the sensitivity of the method to conventional single-passabsorption spectroscopy. The studied microplasma sources are stripline split-ring resonators(SSRRs), with typical ring radii between 3.5 and 6 mm and operation frequencies around2.6 GHz. A linear response (R2 = 0.9999), and a stability of more than 100 s are demonstratedwhen using the microplasma source as an optogalvanic detector. Additionally, saturationeffects at laser powers higher than 100 mW are observed, and the temporal response of theplasma to periodic laser perturbation with repletion rates between 20 Hz and 200 Hz arestudied. Finally, the potential of integrating additional functionality with the detector isdiscussed, with the particular focus on a pressure sensor and a miniaturized combustor toallow for studies of solid samples.
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| 3. |
- Sturesson, Peter, 1981-, et al.
(författare)
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Effect of Resistive and Plasma Heating on the Specific Impulse of a Ceramic Cold Gas Thruster
- 2019
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Ingår i: Journal of microelectromechanical systems. - 1057-7157 .- 1941-0158. ; 28:2, s. 235-244
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Tidskriftsartikel (refereegranskat)abstract
- The research and development of small satellites has continued to expand over the last decades. However, the propulsion systems with adequate performance have persisted to be a great challenge. In this paper, the effects of three different heaters on the specific impulse and overall thrust efficiency of a cold gas microthruster are presented. They consisted of a conventional, printed resistive thick-film element, a freely suspended wire, and a stripline split-ring resonator microplasma source, and were integrated in a single device made from the high-temperature co-fired ceramics. The devices were evaluated in two setups, where the first measured thrust and the other measured shock cell geometry. In addition, the resistive elements were evaluated as gas temperature sensors. The microplasma source was found to provide the greatest improvement in both specific impulse and thrust efficiency, increasing the former from an un-heated level of 44–56 s when heating with a power of 1.1 W. This corresponded to a thrust efficiency of 55%, which could be compared with the results from the wire and printed heaters which were 51s and 18%, and 45s and 14%, respectively. The combined results also showed that imaging the shock cells of a plasma heated thruster was a simple and effective way to determine its performance, when compared to the traditional thrust balance method.
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