Xmpl3d82, 82nd 'example' data file for CPO3DS
Multichannel electron multiplier, tilted channels.
(See xmpl3d81 for non-tilted channels.)
This example is essentially the same as xmpl3d81 except that the channel is tilted by 10 degrees. A further example of a tilt of 25 degrees is given at the end of the data file, and the results from it are mentioned below.
One channel is simulated. It has diameter 0.1mm, length 5mm. The 2 ends are shielded with small field-free boxes. The voltage difference between the ends is 1500V. The channel is tilted by 10 degrees. In Aug 2013 , the users equations option was used to simulate the channel (which is much easier than the method used previously). For details, see shap3d46.
20 electrons are injected with an energy of 100eV.
See xmpl3d81 for a description of the simulation of the secondary production.
The 'minimum incident energy' for collisions is given the value 5eV, so if a primary ray has an energy smaller than this the ray is stopped. This is the main cause of rays not reaching the anode.
3 of the 20 rays reach the anode at the end of the channel (but this small number is a statistical result, the fraction that reach the anode is expected to be higher when more rays are used). They carry a final total current 0.155 mA (before reflections), so 0.310 mA after reflections. The initial total current of the 20 rays is 1.00E-6 mA. Therefore the multiplication factor is 3.10E5 in this example. Interestingly, this is smaller than the value found for the non-tilted channel in xmpl3d81, mostly because secondary rays tend to have a further collision before they can pick up sufficient energy to create more secondaries (but the statistics in these examples are poor).
To investigate the effects of space-charge, which can affect the field along the channel, space-charge iterations should be used.