2134/3215
Jeffrey A. Hopwood
Jeffrey A.
Hopwood
Felipe Iza
Felipe
Iza
Ultrahigh frequency microplasmas from 1 pascal to 1 atmosphere
Loughborough University
2008
untagged
Mechanical Engineering not elsewhere classified
Geology
2008-02-22 16:54:55
Journal contribution
https://repository.lboro.ac.uk/articles/journal_contribution/Ultrahigh_frequency_microplasmas_from_1_pascal_to_1_atmosphere/9546659
The generation of plasma-on-a-chip is examined for two extremes in gas pressure. The application of
microplasmas as sensors of industrial vacuum processes requires stable operation at gas pressures of less than
1 Pa. In this low-pressure regime, the addition of a static magnetic field that causes electron cyclotron
resonance is shown to increase the emission intensity of the microplasma by 50%. Using atomic emission
spectrometry, the detection of helium in air is found to have a detection limit of 1000 ppm, which is three
orders of magnitude worse than the DL of SO2 in argon. The loss of sensitivity is traced to the high excitation
energy threshold of He, and to the poor ionization efficiency inherent in an air plasma. At atmospheric
pressure (105 Pa), a microdischarge is described that operates in a 25 mm-wide gap in a microstrip transmission
line resonator operating at 900 MHz. The volume of the discharge is ~10-7 cm3, and this allows an
atmospheric air discharge to be initiated and sustained using less than 3 W of power.