How to set up step maximum for Calorimeter

[syk1995]

Hi all,
Is there a way to set up a maximum step length in this example?
have a nice day!
yukun shi

[BrieucF]

Hi Yukun,

Yes, you can define limits and apply them to the "region" of your detector. Here is a DD4hep example doing this:

• https://github.com/AIDASoft/DD4hep/blob/master/DDDetectors/compact/SiD_Markus.xml#L184
• https://github.com/AIDASoft/DD4hep/blob/master/DDDetectors/compact/SiD/SiD_TrackerBarrel.xml#L9C120-L9C189

Hope this will help.

Cheers,
Brieuc

[syk1995]

I tried like this, and the G4double stepLength = aStep->GetStepLength() still gives me length greater than 0.5 mm. I need this short step for a another digitization code.

[BrieucF]

Hi,

You also need to add the region to your detector. From the DD4hep example:
<detector id="SiTrackerBarrel_ID" name="SiTrackerBarrel" type="DD4hep_SiTrackerBarrel" readout="SiTrackerBarrelHits" region="SiTrackerBarrelRegion" limits="SiTrackerBarrelRegionLimitSet">

Cheers,
Brieuc

[syk1995]

Hi,
I changed it to

still not working
Cheers,
Yukun

[syk1995]

<detector name="simplecalo2" type="simplecalo2" vis="CaloVis" id ="0" readout="simplecaloRO" region="simplecalo2Region" limits="simplecalo2RegionLimitSet">

[BrieucF]

Hi Yukun,

In this we would need a full reproducer (a list of commands to reproduce the problem) to be able to help you further.

Cheers,
Brieuc

[syk1995]

Hi Brieuc,
I restart with your example simplecalo2, add the limits in the xml file and print in the simplecaloSDAction.cpp(line 130). And it just still doesnt work.
However, it might be easier to diagnose the problem with this one:https://github.com/syk1995/DD4hepTutorials
You can reproduce the problem by ddsim --steeringFile simplecalo2/sc2SteeringFile.py, the setup procedure is just what you said in this tutorial.

[s6anloes]

Hi Yukun,

there are some lines of code missing in the simplecalo2 constructor, to apply the limits to the volume:

You can check out my repository, or add these two lines after line 74 of simplecalo2/src/simplecalo2.cpp:

  CaloVol.setRegion(description, x_det.regionStr());
  CaloVol.setLimitSet(description, x_det.limitsStr());

You should also remove the track length limit from your xml file, since this is a bit too stringent:
<limit name="track_length_max" particles="*" value="5.0" unit="mm" />

You will notice that there are still step lengths above 0.5 mm which originate from photons. At the moment, the limits are only applied to charged particles.
I have asked a question in the DD4hep repo (see above), since I don't know how to apply to neutral particles as well.

I hope this helps you out for now!

[syk1995]

Hi
Sorry for this late reply，I tried your code and it works fine for me！
Currently I only need to limit the charged particle, but I would like to know if you find the way to apply the step length for neutral particles, it may be needed in the future.
Thank you very much for this reply!
Best,
Yukun