THE IONIZATION OF CESIUM IN TUNGSTEN CAPILLARIES,
Abstract
The transport of cesium through a tungsten capillary occurs through two phases, an adsorbed layer and a vapor. In this analysis these two phases are connected by the experimentally observed relationship, rather than by an linearized approximation to it. The choice of allowed solutions is then made by a precise boundary matching to solutions computed for the surface onto which the capillary opens. This analysis leads naturally to the possible existence of three different states of the system for a wide variety of capillary sizes, temperatures, and flow rate conditions. These three states have been correlated with the front surface emitting, pore emitting, and non-emitting states which have been observed to co-exist for a porous ionizer. It is predicted that the coexistence of three different states will disappear when the capillaries become extremely fine. When cesium vapor flows through a heated tungsten capillary the density of adatoms decreases in the direction of flow. The resulting variation in work function leads to contact potential gradients within the pore which accelerate ions in the direction of flow. A consequence of these fields, an enhancing of the ion emission from the capillary, is observed in ion emission micrographs. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1964
- Accession Number
- AD0615932
Entities
People
- A. Theodore Forrester