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Characterization of chemical contaminants and their spectral properties from an atmospheric pressure ns-pulsed microdischarge in neon

Physics of Plasmas

Sillerud, Colin H.; Schwindt, Peter S.; Moorman, Matthew W.; Yee, B.T.; Anderson, John M.; Pfeifer, Nathaniel B.; Hedberg, E.L.; Manginell, Ronald P.

Portable applications of microdischarges, such as the remediation of gaseous wastes or the destruction of volatile organic compounds, will mandate operation in the presence of contaminant species. This paper examines the temporal evolution of microdischarge optical and ultraviolet emissions during pulsed operation by experimental methods. By varying the pulse length of a microdischarge initiated in a 4-hole silicon microcavity array operating in a 655 Torr ambient primarily composed of Ne, we were able to measure the emission growth rates for different contaminant species native to the discharge environment as a function of pulse length. It was found that emission from hydrogen and oxygen impurities demonstrated similar rates of change, while emissions from molecular and atomic nitrogen, measured at 337.1 and 120 nm, respectively, exhibited the lowest rate of change. We conclude that it is likely that O2 undergoes the same resonant energy transfer process between rare gas excimers that has been shown for H2. Further, efficient resonant processes were found to be favored during ignition and extinction phases of the pulse, while emission at the 337.1 nm line from N2 was favored during the intermediate stage of the plasma. In addition to the experimental results, a zero-dimensional analysis is also presented to further understand the nature of the microdischarge.

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TYPE Journal Article YEAR 2017
ScopusOSTIDOI

Fundamental Scaling of Microplasmas and Tunable UV Light Generation

Manginell, Ronald P.; Sillerud, Colin H.; Hopkins, Matthew M.; Yee, Benjamin T.; Moorman, Matthew W.; Schwindt, Peter S.; Anderson, John M.; Pfeifer, Nathaniel B.

The temporal evolution of spectral lines from microplasma devices (MD) was studied, including impurity transitions. Long-wavelength emission diminishes more rapidly than deep UV with decreasing pulse width and RF operation. Thus, switching from DC to short pulsed or RF operation, UV emissions can be suppressed, allowing for real-time tuning of the ionization energy of a microplasma photo-ionization source, which is useful for chemical and atomic physics. Scaling allows MD to operate near atmospheric pressure where excimer states are efficiently created and emit down to 65 nm; laser emissions fall off below 200 nm, making MD light sources attractive for deep UV use. A first fully-kinetic three-dimensional model was developed that explicitly calculates electron-energy distribution function. This, and non-continuum effects, were studied with the model and how they are impacted by geometry and transient or DC operation. Finally, a global non-dimensional model was developed to help explain general trends MD physics.

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TYPE SAND Report YEAR 2016
OSTIDOI

A highly miniaturized vacuum package for a trapped ion atomic clock

Review of Scientific Instruments

Schwindt, Peter S.; Jau, Yuan-Yu J.; Partner, Heather; Casias, Adrian L.; Wagner, Adrian R.; Moorman, Matthew W.; Manginell, Ronald P.; Kellogg, James R.; Prestage, John D.

We report on the development of a highly miniaturized vacuum package for use in an atomic clock utilizing trapped ytterbium-171 ions. The vacuum package is approximately 1 cm3 in size and contains a linear quadrupole RF Paul ion trap, miniature neutral Yb sources, and a non-evaporable getter pump. We describe the fabrication process for making the Yb sources and assembling the vacuum package. To prepare the vacuum package for ion trapping, it was evacuated, baked at a high temperature, and then back filled with a helium buffer gas. Once appropriate vacuum conditions were achieved in the package, it was sealed with a copper pinch-off and was subsequently pumped only by the non-evaporable getter. We demonstrated ion trapping in this vacuum package and the operation of an atomic clock, stabilizing a local oscillator to the 12.6 GHz hyperfine transition of 171Y b+. The fractional frequency stability of the clock was measured to be 2 × 10-11/τ1/2.

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TYPE Journal Article YEAR 2016
ScopusOSTIDOI
Results 26–50 of 95
Results 26–50 of 95