Multifractal behavior of the distribution of secondary-electron-emission sites on solid surfaces

1995 ◽  
Vol 51 (19) ◽  
pp. 13554-13559 ◽  
Author(s):  
Li Hua ◽  
Ding Zejun ◽  
Wu Ziqin
1969 ◽  
Vol 24 (12) ◽  
pp. 1908-1914
Author(s):  
H Oechsner ◽  
W Gesang

The influence of the angle of incidence of low energy ions on the emission of secondary particles from solid surfaces can be investigated by using cylindrical targets in a low pressure plasma. It is shown that the distribution of the angle of incidence of the impinging ions becomes independent of plasma conditions and bombarding parameters, when the diameter of the Langmuir sheath around the target is sufficiently large compared with that of the cylindrical target. Experimental results on the influence of the angle of ion incidence on the secondary electron emission coefficient and the sputtering yield are reported for polycrystalline Mo bombarded with A+-ions from 300 to 900 eV.


1997 ◽  
Vol 55 (18) ◽  
pp. 12086-12098 ◽  
Author(s):  
A. Clouvas ◽  
C. Potiriadis ◽  
H. Rothard ◽  
D. Hofmann ◽  
R. Wünsch ◽  
...  

The electron emission from a number of metal and carbon targets bombarded by various positive ions is measured by a method employing a magnetic field to separate secondary electrons from scattered ions. Molecular ions are shown to produce emission approximately equal to that which would be produced by the individual atoms independently. Accurate measurements have been made of the energy distribution of secondary electrons. These are close to Gaussian. It is concluded that secondary electron emission is confined to the surface layers of the target atoms since no electrons possess energies close to zero.


Author(s):  
R. D. Heidenreich

This program has been organized by the EMSA to commensurate the 50th anniversary of the experimental verification of the wave nature of the electron. Davisson and Germer in the U.S. and Thomson and Reid in Britian accomplished this at about the same time. Their findings were published in Nature in 1927 by mutual agreement since their independent efforts had led to the same conclusion at about the same time. In 1937 Davisson and Thomson shared the Nobel Prize in physics for demonstrating the wave nature of the electron deduced in 1924 by Louis de Broglie.The Davisson experiments (1921-1927) were concerned with the angular distribution of secondary electron emission from nickel surfaces produced by 150 volt primary electrons. The motivation was the effect of secondary emission on the characteristics of vacuum tubes but significant deviations from the results expected for a corpuscular electron led to a diffraction interpretation suggested by Elasser in 1925.


Author(s):  
T. Koshikawa ◽  
Y. Fujii ◽  
E. Sugata ◽  
F. Kanematsu

The Cu-Be alloys are widely used as the electron multiplier dynodes after the adequate activation process. But the structures and compositions of the elements on the activated surfaces were not studied clearly. The Cu-Be alloys are heated in the oxygen atmosphere in the usual activation techniques. The activation conditions, e.g. temperature and O2 pressure, affect strongly the secondary electron yield and life time of dynodes.In the present paper, the activated Cu-Be dynode surfaces at each condition are investigated with Scanning Auger Microanalyzer (SAM) (primary beam diameter: 3μmϕ) and SEM. The commercial Cu-Be(2%) alloys were polished with Cr2O3 powder, rinsed in the distilled water and set in the vacuum furnance.Two typical activation condition, i.e. activation temperature 730°C and 810°C in 5x10-3 Torr O2 pressure were chosen since the formation mechanism of the BeO film on the Cu-Be alloys was guessed to be very different at each temperature from the results of the secondary electron emission measurements.


Author(s):  
E. F. Lindsey ◽  
C. W. Price ◽  
E. L. Pierce ◽  
E. J. Hsieh

Columnar structures produced by DC magnetron sputtering can be altered by using RF biased sputtering or by exposing the film to nitrogen pulses during sputtering, and these techniques are being evaluated to refine the grain structure in sputtered beryllium films deposited on fused silica substrates. Beryllium is brittle, and fractures in sputtered beryllium films tend to be intergranular; therefore, a convenient technique to analyze grain structure in these films is to fracture the coated specimens and examine them in an SEM. However, fine structure in sputtered deposits is difficult to image in an SEM, and both the low density and the low secondary electron emission coefficient of beryllium seriously compound this problem. Secondary electron emission can be improved by coating beryllium with Au or Au-Pd, and coating also was required to overcome severe charging of the fused silica substrate even at low voltage. The coating structure can obliterate much of the fine structure in beryllium films, but reasonable results were obtained by using the high-resolution capability of an Hitachi S-800 SEM and either ion-beam coating with Au-Pd or carbon coating by thermal evaporation.


Sign in / Sign up

Export Citation Format

Share Document