THE GENERATION OF CHARGED COLLOIDS FOR ELECTRIC PROPULSION VIA HETEROGENEOUS CONDENSATION IN VACUUM OF METAL VAPORS ON A SURFACE.
Abstract
As an approach to the in situ generation of charged colloids for electric propulsion, a heterogeneous condensation method was investigated. The method comprised two distinct steps; first, the formation of neutral particles by the controlled vacuum deposition of metal vapor onto a solid substrate, and second, the inductive charging and electrostatic separation of the particles from the substrate by a strong electric field. Particles ranging in diameter from below 50 to more than 500 Angstroms were readily formed by condensing lead, silver, and copper vapors upon plastic or carbon substrates. Background pressures were in the 0.00001 torr range, substrates were at room temperature or 300 C, vapor beam intensities at the substrate were about 10 to the 15th power atoms/sec cm sq, and deposition times varied from about 2 seconds to 200 seconds. Some experiments with a time-of-flight particle removal and detection system gave evidence that particles had been extracted from the substrate, acquiring charge-to-mass ratios up to 3000 coulombs per kilogram. If such particle charging and removal had in fact occurred, only a small fraction of the total deposit could have been involved. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1964
- Accession Number
- AD0617120
Entities
People
- Bernard Hornstein