Xmpl2d37, 37th 'example' data file for CPO2D
Illustration of the scattering option, production of secondary electrons
This example file is available only in the 'special' scattering version of CPO2D or CPO2DS.
The geometry is that of xmpl2d26.
100 rays start at z = -0.5, with energy 1000eV, in a field-free region.
When the rays hit the electrode at z=1 (but see below) they produce secondary electrons. Some of these rays are backscattered electrons that have the original energy so when they hit the electrode at z = -1 these produce further secondaries.
The external 'user-supplied' routine that defines the scattering function is in file sct2secd.cpp, which is supplied with the CPO2D package. It should be copied to scatter2.cpp and used to create scatter2.dll, as explained in Help.
This routine calls the data file sct2secd.dat (also supplied with the package), which is named by the user in the databuilder. It starts (but without the comments):
2010 = seed
z = a plane for production of secondaries (any number of repeats of this line)
z = a plane for production of secondaries (any number of repeats of this line)
n = no more planes
0.99 = constant value to define 1st plane listed above
-0.99 = constant value to define 2nd plane listed above
0 = min energy
5 = max energy of secondary distribution,
100 = number of values for maxwell distribution
0.03586 = values
0.07579
...
It can be seen from the data in sct2secd.dat that the secondaries are produced at z = +/-0.99, not at the positions of the electrodes, z = +/- 1.0. The reason for this is that there can be a conflict between the present option to produce secondaries and the option to stop when an electrode is hit (which is activated here). So to avoid this conflict the positions for secondary production are 0.01mm from the respective electrodes and also the step length for ray tracing is reduced to 0.01 in these regions (using an 'advanced' option).
Note also that the discontinuity in the ray path can cause difficulties for the ray plotting routines, and so the ray path on the screen might appear to be kinked. This is avoided here by using 0 interpolation points.
Please see sct2secd.cpp for further detailed information.
Internal options are also available for producing secondary electrons, see xmpl2dn where n = 26 and 39, and xmpl3dn where n = 49 and 61.
See also xmpl3d58.