The initial SE (secondary electrons) angular-distribution as SEs leave the emitting
surface is predicted to follow a cosine distribution 
Here, δ0 is the SE yield at α = 0°. Figure 4832a shows the SE
angular-distribution for our polycrystalline gold sample at electron beam energy of 1.5 keV.
Figure 4832a. SE angle-resolved yield data for
polycrystalline Au with electron beam energy of 1.5 keV.
curve fits the data using the cosine distribution of Equation . 
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 angular-distributions 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 .
 J. H. L. Jonker, The angular-distribution of the secondary electrons of
nickel, Philips Res. Rep., 6, 372-387,1951.
 N. Nickles, R. E. Davies and J. R. Dennison, Applications of Secondary Electron Energy- and Angular-Distributions to Spacecraft Charging, 6th Spacecraft Charging Technology Conference, AFRL-VS-TR-20001578, 1 September 2000.