The OPAL Discussion Forum

[Andreas Adelmann <andreas.adelmann AT psi.ch>]

On 28.08.2011, at 06:57, wangchuan02513 wrote:

Hi, Andreas,
The tot_sey stands for the sum of sey value per time step. Whenever a particle hit the surface, our secondary emission model will calculate the sey value according to both the impact energy and the sey curve of the surface material, then secondary model will use monte carlo process to determine the exact number of secondaries emitted by one impacting issue. If we sum those sey value in each time step for all the particles which hit the surface during this time step, we get the tot_sey value. So this sey_tot value does not exactly count the particles that generated by secondary process but they are related.

ok I understand now!

For the case we multiply the charge with the sey value, instead of emitting multiple secondaries with the same charge, like the case I sent you, this tot_sey value has less meaning because each particle may have different charge. 

The last column of the PartStatistics.dat is the effective number of particles in simulation domain, i.e, the tot charge divided by the initial charge of one initial particle.

Here I am still confused: on one hand (in the last sentence above) you assume constant charge per particle and before you write " because each particle may have different charge".

Can you clarify this ? Does every particle has the same charge or not. If this is not the case N = Q_{tot}/Q_{initial} does not make sense to me.

Best Andreas
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Dr. sc. math. Andreas (Andy) Adelmann
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