The OPAL Discussion Forum

[Arnau Albà <arnau.alba AT hotmail.com>]

Hi Dragos,

For the particle deletion there is the SOURCE element 

https://amas.web.psi.ch/opal/Documentation/master/OPAL_Manual.html#sec.elements.source

I'm not sure about the reference particle question, I would have to think about it. Or perhaps someone else knows.

Best,

Arnau

On Mon, 13 May 2024 at 18:53, Dragos Constantin <dragos.constantin AT gmail.com> wrote:

Hi All,
I have a model where I am emitting electrons at the beginning of a set of
adjacent RF cavities. The emission time lasts a few RF cycles and mimics
continuous electron injection from a thermionic electron gun. As expected some
of the macroparticles are pushed back during the bunching process, and some of
these macroparticles will continue to propagate in the negative z-direction
past the emission point.

What is the best way to discard the particles that move in the negative z-
direction? I am thinking to discard any particle that propagate behind the
cathode (the emitting surface).

The second issue relates to the initial coordinates of the reference particle.
I know the reference particle starts in (x,y,z)=(0,0,z_start). Is there a way
to specify the (x,y) coordinates for the reference particle starting point?
Depending on the simulation input parameters, sometimes I loose the reference
particle after several RF cavities. More generally what is the best strategy
to make sure the reference particle 'survives'?

Thanks,
Dragos