The OPAL Discussion Forum

[Christof Metzger-Kraus <christof.j.kraus AT gmail.com>]

Hi Dragos,

I would have done it the same way by adding a collimator behind the cathode. If you placed the collimator with a negative ELEMEDGE then the negative value could be the problem. Try to place it with 3D coordinates. 

Could you send me the input file? Then I can try to find the cause for the segfault. 

Best regards 

Christof 

Dragos Constantin <dragos.constantin AT varian.com> schrieb am Sa., 18. Juli 2020, 06:47:

Hi All,
I believe I have confused everyone with my previous question as I've failed to
provide the details. So here is what I am doing with the AWAGun example:

1. I have increased 100x the TPULSEFWHM
2. I have also increased 100x the EMISSIONSTEPS (to keep the emission time
step constant)

I did this because I want to model an emitted DC beam current and I am using
the AWAGun as a toy model. Because of this setup, I have a very long electron
slug which will be 'bunched' in the RF Gun 'cavity'. This way I can see
several electron bunches being created. These bunches are obviously longer
than the original bunch described by the initial distribution. At the same
time, half the electrons are pushed back and they move in the negative z-
direction.

As I was saying in my previous email, I've tried to get rid of those
electrons, i.e the ones with negative axial momentum, but I was not
successful. Do you have any suggestions on how I can achieve this?

Thanks
Dragos