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Forum: Hadronic Processes
Re: None Problems with neutron HP and LEND with Argon interactions (Matthew Blackston)
Re: Note Re: Problems with neutron HP and LEND with Argon interactions (Matthew Blackston)
Re: None Re: Problems with neutron HP and LEND with Argon interactions (michel maire)
Date: 30 Jan, 2018
From: Matthew Blackston <Matthew Blackston>

Thank you very much for running your test Michel! It allowed me to find my problem and it has nothing to do with problems with argon. Rather, it was how I was defining my material. I had inadvertently set the temperature of my argon to -1K and this was causing the problems in both the elastic and inelastic interactions that I was seeing.

If anyone is interested, you can test this by modifying the MaterialWithSingleIsotope method in the DetectorConstruction class of Hadr03 so that the material was defined as such:

    G4Material* material = 0;
    if(name=="Ar40") material = new G4Material(name, density, ncomponents=1, kStateLiquid, -1.0);
    else material = new G4Material(name, density, ncomponents=1);
    material->AddElement(element, massfraction=100.*perCent);

The only other changes I made were to turn elastic scatters back on and modify the density of the Argon in the Ar40.mac that Michel attached in his message. The results are attached. As you can see, the elastic scatters produce no recoil Ar40 and the (n,3n) reaction shows up when it shouldn't.

Putting the argon at a reasonable temperature fixed both the elastic and inelastic problems. I wonder if the G4Material class should be doing a check for a negative temperature and throwing an exception if the user attempts to do this?

Your test gave me a benchmark from which to discover the problem. Many thanks!

   Attachment:
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2018/01/30/08.26-23492-Ar40_negTemp.out

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