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Question Negative Current Interaction Length with Photonuclear interaction, and other problems 

Keywords: monopole processes
Forum: Event and Track Management
Date: 06 Jun, 2005
From: Giles Reid <gar44@student.canterbury.ac.nz>

Hello,

I'm trying to simulate magnetic monopoles in GEANT. I am currently using a modified mu+ with charge 68.5 and mass of around 300GeV.

I've been trying to get the Photonuclear interaction process to work, using the base of the MuonProcess example, but when I add the process I get the following error:

*** G4Exception : Negative currentInteractionLength
      issued by : G4VProcess::SubtractNumberOfInteractionLengthLeft()

All of the PostStepDoIt outputs above this error contain nans for various parameters like momentum and total energy.

So my first question is, can the Muon Photonuclear code be expected to work for high charges and masses, or would it need to be rewritten?

I have been able to modify the PairProduction model to include extra factors of the monopole charge and this appears to give reasonable results. I have also found that the MuIoni process doesn't work very well, but the hIoni one does. The problem is, I can't make pair production and ionisation work simultaneously, because when I use hIoni with the Muon along with Pair Production I get a segmentation fault in the line:

theDEDXTable->GetFlag(i)

in G4VEnergyLossProcess.cc.

I realise that having hadronic and muon processes may be causing the problem. However, in order to make the simulations realistic I need to have the Pair Production and Photonuclear Processes working, and as far as I can tell there is no hadronic equivalent to these processes in GEANT.

Any help would be greatly appreciated.

Giles Reid.

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1 None: Re: Negative Current Interaction Length with Photonuclear interaction, and other problems   (Vladimir IVANTCHENKO - 06 Jun, 2005)
(_ None: Re: Negative Current Interaction Length with Photonuclear interaction, and other problems   (Giles Reid - 06 Jun, 2005)
(_ None: Re: Negative Current Interaction Length with Photonuclear interaction, and other problems   (Vladimir IVANTCHENKO - 07 Jun, 2005)
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