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The secondary
electrons (SEs) are known to be emitted with a cosine polar distribution normal to
the emitting surface. Therefore, the initial SE (secondary electrons) angulardistribution as SEs leave the emitting
surface is predicted to follow a cosine distribution [1]
 [4832]
where,
δ_{0}  the SE yield at α = 0°.
α  the angle from the normal of
the emitting surface.
Figure 4832a shows the SE
angulardistribution for our polycrystalline gold sample at electron beam energy of 1.5 keV.
Figure 4832a. SE angleresolved yield data for
polycrystalline Au with electron beam energy of 1.5 keV.
The
curve fits the data using the cosine distribution of Equation [4832]. [2]
Figure 4832b shows the radial spread of emission of secondary electrons from a point source. Here, it shows cartesian coordinates on the sample surface.
Figure 4832b. Radial spread of emission of secondary electrons from a point source. Here, cartesian coordinates is used on the sample surface.
SE angulardistributions can be measured with a rotatable Faraday cup retarding field analyzer for a range of fixed emission angles between 18° and +73° with respect to the sample normal [2].
[1] J. H. L. Jonker, The angulardistribution of the secondary electrons of
nickel, Philips Res. Rep., 6, 372387,1951.
[2] N. Nickles, R. E. Davies and J. R. Dennison, Applications of Secondary Electron Energy and AngularDistributions to Spacecraft Charging, 6th Spacecraft Charging Technology Conference, AFRLVSTR20001578, 1 September 2000.
