Mass spectrometry of ions from xenon radiofrequency discharges

Kohout, F. C.; Neiswender, D. D.

doi:10.1016/0020-7381(70)85018-5

Cited by 7 publications

(1 citation statement)

References 27 publications

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“…Plasma diagnostics can be performed by sampling a plasma through a tiny orifice in the container wall into a low-pressure collection region. Widespread use has been made of such orifices both on space vehicles (Hanson et a1 1970, 1973, Knudsen 1966) and in laboratory plasmas (SCguin et a1 1972, Kohout and Neiswender 1970); in fact, whenever energy analysers and mass spectrometers are employed. Previously (Prokopenko et al 1972), an orifice probe was described for the measurement of the electron temperature Te, number density He, and space potential V, from the total current characteristic.…”

Section: Introductionmentioning

confidence: 99%

Orifice probe for plasma diagnostics: II. Multi-parameter analysis

Prokopenko¹,

Laframboise²,

Goodings³

1974

J. Phys. D: Appl. Phys.

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A multi-grid orifice probe and analysis technique are presented which permit the measurement of the following plasma parameters: the electron number density ne, the electron temperature Te, the space potential Vs, and an estimate of the metastable number density nm. Simultaneously, the analysis allows the quantitative determination of instrumental parameters such as the reflection coefficient for slow (<30 eV) electrons from the grids Re(G) and roughened (gold-black) collector Re(C), the secondary electron emission coefficient for fast (> 30 eV) electrons γe(G) from the grids, and the effective transparencies of the grids for electrons τe(G), and for metastables τm(G). Experimental ion, electron and total current characteristics are presented for a low-pressure (1·8×10−2 Torr) RF discharge in argon. The major part of the analysis method involves the use of ten `plateau values' obtained from the characteristics to determine values for most of these parameters. Te and Vs are determined separately. The values obtained are: ne=2·74×109 cm−3±18%, kTe=1·92 eV±5%, Vs=11·7±0·1 V, nm similar, equals 3·3×109 cm−3±50%, Re(G)=0·65±0·10, Re(C)=0·22±0·10, γe(G)=0·935±0·010, τe(G)=0·830±0·002, and τm(G)=0·850±0·002. The transparencies τe(G) and τm(G) are within 4% of the geometrical transparency τ(G)=0·860. Approximately equal numbers of atoms (1 in 2×105) are in metastable and ionized states.

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