Cesium vapor

Vacuum Tubes. In the manufacture of vacuum tubes for use in polarized ion sources, vaporized cesium is used as a getter for residual gaseous impurities in the tube and as a coating to reduce the work function of the tungsten filaments or cathodes of the tube. The cesium vapor is generated by firing, at about 850°C within the sealed and evacuated tube, a cesium chromate pellet and zirconium (12) (see Vacuum technology). 

Cesium superoxide, 5 700 Cesium tetrachlorogold, 5 701 Cesium tetrahydroborate, physical properties of, 4 194t Cesium trifluoroacetate, 5 701 Cesium vapor thermionic convertor, 5 704-705 Cesspools, 25 915... 

Sorokin and Lankard illuminated cesium and rubidium vapors with light pulses from a dye laser pumped by a ruby giant-pulse laser, and obtained two-step excitation of Csj and Rbj molecules (which are always present in about 1 % concentration at atomic vapor pressures of 10" - 1 torr) jhe upper excited state is a repulsive one and dissociates into one excited atom and one ground-state atom. The resulting population inversion in the Ip level of Cs and the 6p level of Rb enables laser imission at 3.095 jum in helium-buffered cesium vapor and at 2.254 pm and 2.293 /zm in rubidium vapor. Measurements of line shape and frequency shift of the atomic... 

Fig. 3. Eloetron-optical reproduction of a crystalline nickel plate emitting thermionic electrons in cesium vapor [according to Schenk (31)].

Fi(i. 13. Distribution of thermionic electron emission of a tungsten-monocrystal wire in cesium vapor in the [Oil] zone at A 2,000°, B 900°, C 850°K. Cesium vapor pressure corresponds to room temperature [according to Johnson and Shockley (35)]. 

Figure 4. Effect of carrier-gas molecular weight on cesium vaporization rate. The geometric parameters in these experiments are = 1,2 cm., b = 0,8 cm.

It is also possible to produce He(23S) atoms by the charge exchange of He+ ions in cesium-vapor.93 This technique has been used extensively by the Stanford Research Institute (SRI) group to measure differential cross sections at higher energies (5 to 10 eV). Some of the data94 in reduced units... 

Rudat (29) has taken the nozzle from a Capillaritron gun and mounted it on his spectrometer source. Because of the small distance between gun and target, sufficient ion bombardment is attained at very low gun currents. Closely related to this work is that of McEwen who mounted a cesium gun on his ionization source (30). The gun functioned by using a filament to heat cesium chloride salts that drove off the cesium. Before emerging from the gun toward the target, cesium vapor is surface ionized by the filament, then accelerated by the impressed moltage. 

Thermionic converters are high temperature devices which utilize electron emission and collection with two electrodes at different temperatures to convert heat into electric power directly with no moving parts. Most thermionic converters operate with a plasma of positive ions in the interelectrode space to neutralize space charge and permit electron current flow. Both the plasma characteristics and the surface properties of the electrodes are controlled by the use of cesium vapor in thermionic diodes. 

When Na92-X was exposed to cesium vapor at 450 °C, redox reaction went to completion to give sodium metal, which left the zeolite, and CS92-X. The reaction did not stop at that point, however. Thirty-six additional atoms of cesium were sorbed per unit cell. It appears from the structure that six Cs cations did not participate in this latter reaction, but that the remaining 86 Cs ions had reacted with the 36 Cs atoms to give a cationic continuum of formula (Csi22) cell.35,36 jjus continuum is three dimensional,... 

Timgsten exhibits an excellent chemical stability against cesium vapor at elevated temperature up to 1900°C. This is of importance for the application of tungsten in ionic propulsion systems in spacecrafts. 

Thermionic emitter in spacecrafts (W, CVD-W, W—Re). The important properties are high-temperature resistance and stability against cesium vapor. 

Figure 1 shows two versions of such converters assembled around a planar variable-spacing research converter body built by ThermoTrex one was fitted with a collector whose cavity contained 0.6g of CsO, the other had a porous W disc in which CsQ had soaked in after melting. In both cases cesium vapor was supplied by an outside liquid reservoir. 

Cesium Vapor Reacts with K+-Exchanged Zeolite A To Give Fully Cs+-Exchanged Zeolite A Containing (CsJ3 Clusters... 

HEO SEFF Cesium Vapor Reacts with K -Exchanged Zeolite A 179... 

After complete dehydration, (14) cesium (99.98% purity, Johnson Matthey Inc.) was distilled from a side-arm breakseal ampoule to the glass tube extension of the crystal-containing capillary. This glass reaction vessel was sealed off under vacuum and placed within two cylindrical coaxially attached horizontal ovens. The oven around the crystal was maintained at 350 °C for 16 hours, while the oven around the distilled cesium was at 209 °C to give 0.1 torr of cesium vapor in the entire reaction vessel. (18) The capillary was then allowed to cool (after the cesium source had cooled) and was sealed off from the reaction vessel with a small torch while still under vacuum at 25 C. An examination of the product under the microscope showed that the colorless crystal of dehydrated had... 

The K+ ions in dehydrated K -A were completely reduced by 0.1 torr of cesium vapor at 350 °C. The product, fully dehydrated, fully Cs+-exchanged zeolite A, Cs 2 A 3/4Cs, contains extra cesium atoms... 

Cesium Vapor Reacts with fC-Exchanged Zeolite A 189... 

A detailed description of the interacting beams apparatus used in the present work can be found elsewhere [12], In short, positive ions are extracted from a plasma-type ion source and accelerated to beam energies that can be varied between 2.5 and 5 keV. Negative ions are produced in the beam by double sequential charge exchange in a cesium vapor. A pair of electrostatic quadrupole deflectors (QD1, QD2) is used to direct the negative ion beam into and out of the path of the laser beams, as shown schematically in Fig. 2. The ion-laser interaction region is defined... 

Renkert H, Hensel F and Franck E U 1969 Metal-nonmetal transition in dense cesium vapor Phys. Lett. A 30 494... 

Generally, there are three types of instruments used to detect ordnance cesium vapor magnetometers, radio telemetry (common metal detectors). 

---