xmpl3d46, 46th 'example' data file for CPO3D
Creation of secondaries, using Maxwell, Lambert and Poisson distributions.
See also xmpl3d58, in which an external program is used to generate the secondaries, using the scattering version of cpo3ds.
100 rays hit an electrode and produce secondaries.
The energies, directions and currents of the secondaries are measured when they reach a test plane.
3 options are triggered in this example:
A Maxwellian distribution of the energies of the secondaries.
A Lambertian (cosine) distribution of directions.
A Poisson distribution of the currents.
Details of these options are given in Help.
The formula for the mean multiplication factor per collision is taken from A. V. Raspereza et al, Submicrochannel plate multipliers, Applied Surface Science 111 (1997) 295-301.
The formula is
fmean = fmax*exp(-am*(1. - cs))*4.*x/(1. + x)**2
x = sqrt(cs)*energy/emax
According to Raspereza et al (see above):
fmax emax am
Lead glass 4.0 250 0.5
Alumina 4.8 350 0.5
In the present example the actual multiplication factor is distributed about the mean according to the poisson distribution.
Raspereza et al also say that the secondary electrons have a Maxwellian energy distribution, mean value 2.0ev, and a cosine angular distribution.