Engineering topics

Kuehn, D. G.

Publications and source records attributed to Kuehn, D. G..

2 records

NASA NTRS1980

Interference with negative particle sampling due to formation of positive ions in a quadrupole mass spectrometer

A quadrupole mass spectrometer has been utilized to study active discharges containing Cs vapor. Production of positive ions by electron impact within the mass spectrometer and subsequent secondary electron emission from cesiated surfaces produced spurious or pseudonegative ion signals which interfered with attempts to sample negative ions from the plasma. These effects may also occur in other gas discharge systems.

Kuehn, D. G.↗

NASA NTRS1978

Negative and positive cesium ion studies

Mass spectrometric analyses have been performed on the positive and negative species from discharges in Cs, He-Cs, and He-H2-Cs mixtures. Sampling was conducted through the electrodes of normal glow discharges and from close-spaced heated-cathode conditions, which approximate a cesium thermionic converter. No negative Cs ions were observed for Cs pressures less than .01 torr. Identified species included Cs(+), Cs2(+), Cs(-), and what appeared to be multiply charged ions. Low-mass negative and positive ions attributed to H2 were observed when an He-H2 mixture was also present in the discharge region.

Kuehn, D. G.↗