PHOTOEMISSIVE SURFACES
Abstract
The thermionic and photoelectric emissions were measured as Cs was added to an oxidized Ag sheet. Two photoelectric and 2 thermionic emission maxima were found, but their yields were not proportional. The gross Cs/O atomic ratio was generally less than 2.0 throughout the time range for which the infrared response (photoelectric emission) was appreciable. At the maximum thermionic emission the Cs content was less than that corresponding to Cssub2O, which supports the hypothesis that Cssub2O is not the only oxide present in the photocathode at equilibrium. The mechanism of the reaction was studied by stopping the Cs flow at various stages. Only a fraction of A Cs monolayer seems required for minimum work function, and the reaction rate is proportional to the Cs surface concentration. As the concentration is reduced, the rate falls so low it is not perceptible. Photocathode composition was determined by using Si-Cs chromate mixtures, which produce Cs upon heating, with radioactive Cs tracer. A Fourier prrojection of electron density was computed from corrected experimental intensity measurements; the projection indicated some polarization of Cs+ in the crystal field.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 12, 1952
- Accession Number
- AD0000242
Entities
People
- E. N. Lassettre
Organizations
- Ohio State University