Density of a Thorium Monolayer for Maximum Thermionic Emission
- 1 October 1960
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 31 (10), 1715-1717
- https://doi.org/10.1063/1.1735431
Abstract
An investigation is described in which a high‐sensitivity analytical balance of standard design is used for determination of the surface density of that thorium layer which corresponds to maximum thermionic emission with the thorium‐on‐tungsten system. Following Brattain and Becker's definition of this value of surface density as one ``f unit,'' thorium vapor is allowed to accumulate on a quartz plate until a weighable number of f units (about 600) has been deposited. The thorium flux in f units per minute is monitored periodically by means of a tungsten filament diode during the course of the deposition. Two polycrystalline specimens of ribbon from the same source have yielded the value of (4.2±0.2)1014 atoms/cm2 as the density for maximum emission. This is to be compared with a value of 5.0×1014 atoms/cm2 obtained in 1934 on theoretical grounds by Langmuir.Keywords
This publication has 5 references indexed in Scilit:
- Adsorption of Strontium and of Barium on TungstenThe Journal of Chemical Physics, 1955
- Thoriated tungsten filamentsJournal of the Franklin Institute, 1934
- Thermionic and Adsorption Characteristics of Thorium on TungstenPhysical Review B, 1933
- VAPOR PRESSURES, EVAPORATION, CONDENSATION AND ADSORPTIONJournal of the American Chemical Society, 1932
- Thermionic and Adsorption Characteristics of Caesium on Tungsten and Oxidized TungstenPhysical Review B, 1926