Feature #803

energy deposition in SciFi is too small

Added by Santos, Edward over 12 years ago. Updated over 12 years ago.

Target version:
Start date:
22 November 2011
Due date:
% Done:


Estimated time:
New Issue


It's been a while since I looked at simulation. Now, I'm having problems running tracker reconstruction with the recent updates in the simulation code. The issue comes down to this: energy depositions in the fibres are too small. They are either 0 or something of the order 10^(-10) keV. Typical values like the ones we used to have before (~ 0.04 keV) are very(!) rare.

The energy deposition in a fibre is retrieved using the member function GetTotalEnergyDeposit() of the class G4Step.

This whole problem is not due to secondaries, I'm running an almost pure muon beam with large threshold for delta ray production. Datacard input and simulation output are attached.

Help? Ideas?


datacard (4.89 KB) datacard input datacard Santos, Edward, 22 November 2011 15:19
simulation.out (271 KB) simulation.out output of the simulation Santos, Edward, 22 November 2011 15:19
energy_deposited.png (9.04 KB) energy_deposited.png Rogers, Chris, 16 December 2011 10:58
santos_run.tgz (68 KB) santos_run.tgz Rogers, Chris, 16 December 2011 10:58

Updated by Rogers, Chris over 12 years ago

  • Category set to Simulation
  • Assignee set to Rogers, Chris
  • Target version set to Future MAUS release

The only changes I made that I would expect to affect this are that I made some physics parameters user-defined. But I believe I kept the defaults the same. So I'm a bit surprised.

I see in your datacards you set the production threshold to 100 mm, this probably is causing the different behaviour. Try using instead the default 0.5 mm. It would be useful to know how the variation in this parameter affects your physics - smaller values => slower simulation, larger values => less accuracy. Probably 0.5 mm is too small, probably 100 mm is too large.

Nb: explicitly, the only checks I make when changing code are the tests. If you care about some physics, make it a test, otherwise I won't check it.


Updated by Rogers, Chris over 12 years ago

I'm not sure I understand - I tried making a histogram of your simulation.out file and see mean "energy_deposited" of 0.0484 MeV in the SciFi SD Hits. This I also see when I run it myself. Sample histogram is attached (plus a copy of my own run log etc).


Updated by Rogers, Chris over 12 years ago

  • Assignee changed from Rogers, Chris to Santos, Edward

Need more info...


Updated by Rogers, Chris over 12 years ago

  • Status changed from Open to Rejected

I think this is no longer valid. Reopen if I'm wrong

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