L'émission exoélectronique des corps solides

Chemiemission from the cesium-oxygen surface reaction

“…From the maximum emission current, knowing the oxygen pressure p and the area of the cesium surface A, it is possible to determine the maximum differential yield /max = uAY-d ß = (spA Fmie)/ (V 2-irmkT) (1) where u = sp/V2wmkT is the rate of adsorption of molecules per square centimeter of exposed surface area,16 s is the sticking probability (fraction of collisions which results in adsorption), FDM is the maximum differential yield (fraction of adsorptions which results in emission), and the other symbols bear their conventional meanings. For oxygen gas at room temperature, the pressure expressed in Torr, and a surface area of 5 cm2, one obtains sFdm = /max/287p (2) From the total emission Q, knowing the number of cesium atoms per unit surface area and the surface area Figure 3. Variation of emission current with time, under constant pressure of oxygen, for a thick cesium film, previously reacted with oxygen and then annealed at base system pressure for 6 min.…”

“…Effects of Surface Preparation. Several different classes of cesium surfaces could be distinguished in these experiments: (1) thin films deposited on a gold substrate; (2) thick films deposited on a gold or cesium oxide substrate; (3) thin films deposited on a cesium oxide substrate; and (4) films developed by annealing oxide-coated thick films.…”

“…The cesium metal was held in a break-seal ampoule which was opened under ultrahigh vacuum by Figure 2. Cesium-oxygen reaction site (schematic): (1) dewar flask; (2) side arm for cleaning; (3) cesium evaporation tube; (4) glass-encased iron slug; (5) cesium ampoule; (6) gold electron collector; (7) gold baffle; (8) deposition site. means of a Pyrex-encased iron slug.…”

Colour Centre Photoelectric Image Storage Target

“…Bohun [2] reports that PSEE is observed in coloured NaCl under pressures higher than 1 x 10-5 Torr only. Below this value no emission was recorded, indicating that a decrease of the electron affinity of the surface probably occurred l) Part of a communication to the 3rd International Symposium on Exoelectrons, PTB Braunschweig, July 4, 1970.…”

The Early Detection of Fatigue Damage

“…The first comprehensive discussion of this subject took place in an exoelectron conference held in 1956 in Austria. A number of reviews (Grunberg, 1958;Mueller, 1961;Bohun, 1963;Bohun, 1965;Ramsey, 1965;Brotzen, 1967) have been published since then. Because exoelectron emission can be excited in a variety of ways, there is much confusion in the literature on the mechanism of emission.…”