Only visualizing tracks with certain particles

Recording, Visualizing and Persisting Data
1

Hey all,

I have a simulation where I am investigating electron bremsstrahlung. Of course, only a handful of the actual events produce any photons (generally about 1 in every 1000). I want to produce a figure where I only see tracks for which a photon was produced, is there an easy way to do this that won’t require me to manually sort through every event?

2

Take a look at the “trajectory filtering” visualization commands in the Developer’s Guide: Trajectory Filtering — Book For Application Developers 11.0 documentation

3

Thank you for the reply, I have tried the trajectory filtering but the problem is I can’t seem to filter an entire event based on one of the particles within the event. When a photon is produced I want to see the electron trajectory as well.

4

Oh, that’s different from what you described (“I want to produce a figure where I only see tracks for which a photon was produced”). I believe there’s a way, for instance in your stepping action, to “flag” an event for display. If you put a check in your stepping action to see if a secondary is a photon, then you should be able to do this. The same chapter in the Developer’s guide should talk about this.

5

Yes. If you can identify the event(s) you want to see in, say, your stepping action, you can “keep” them:

if ( some criterion ) {
  G4EventManager::GetEventManager()->KeepTheCurrentEvent();
}

and they will be available for viewing at the end of run with /vis/reviewKeptEvents - see guidance - help /vis/reviewKeptEvents).

You may also /vis/drawOnlyToBeKeptEvents and see only the kept events during a run.

This is documented in Controlling Visualization from Commands — Book For Application Developers 11.0 documentation, Additional Note 2.

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