Different Energy Deposit between msc and DWPACoulombScattering

Physics Processes, Models and Cross Sections
1

Information of My PC

Geant4 Version: 11.2.1
Operating System:Ubuntu 22.04
Compiler/Version:gcc 12.03
CMake Version:3.22.1

Problem

I used the G4EmStandardPhysics_option4 and G4EmStandardPhysicsSS for my Em process.And the Energy Deposit for eIoni and sacttering process is different.

My Code

For my material

G4Element *elC = nist_manager->FindOrBuildElement("C");
    G4Element *elH = nist_manager->FindOrBuildElement("H");
    G4Element *elCl = nist_manager->FindOrBuildElement("Cl");
    G4Element *elO = nist_manager->FindOrBuildElement("O");
    G4Element *elSb = nist_manager->FindOrBuildElement("Sb");

    G4Isotope *Sr_90 = new G4Isotope("Sr90", 38, 90);
    G4Isotope *Sr_88 = new G4Isotope("Sr88", 38, 88);

    G4Element *elSr = new G4Element("Strontium", "Sr", 2);
    elSr->AddIsotope(Sr_90, 100.*1. / 5000);
    elSr->AddIsotope(Sr_88, 100* (1. - 1./5000));

    G4double density = 1.8109 * g/cm3;
    G4Material *crystal = new G4Material("Crystal", density, 6);
    crystal->AddElement(elC, 24);
    crystal->AddElement(elH, 52);
    crystal->AddElement(elCl, 7);
    crystal->AddElement(elO, 14);
    crystal->AddElement(elSb, 1);
    crystal->AddElement(elSr, 2);

For My Physics

else if (particleName == "e-") {
            
             G4CoulombScattering* ss = new G4CoulombScattering();
            if(G4EmParameters::Instance()->UseMottCorrection()) {
                ss->SetEmModel(new G4eDPWACoulombScatteringModel());
            } else {
                ss->SetEmModel(new G4eCoulombScatteringModel(false));
            }
           G4eIonisation *eIoni = new G4eIonisation();
            eIoni->SetEmModel(new G4LivermoreIonisationModel());
            G4eBremsstrahlung *eBrem = new G4eBremsstrahlung();
            eBrem->SetEmModel(new G4LivermoreBremsstrahlungModel());
            ph->RegisterProcess(eIoni, particle);
            ph->RegisterProcess(eBrem, particle);
            ph->RegisterProcess(ss, particle);
            
        }

Result

Physics List Process Step number Energy Deposit Model Total Edep /Event
EmStandardPhysicsSS eIoni 11729 128.47 keV Livermore 203.03 keV
Bremsstrahlung 2302 184.12 keV Livermore
CoulombScattering 230865917 20.302 GeV eCoulombScattering
phot 38 182.47 keV Livermore
EmStandardPhysicsSS_msc eIoni 60716 7.808 GeV Livermore 167.41 keV
— — — — — —
Bremsstrahlung 1616 45.24 MeV Livermore
CoulombScattering 697288 8.8876 GeV msc
phot 40 148.76 keV Livermore
2

Hello,

it is known feature of SS/Opt4 /Opt0 differences. In condense history approach not only multiple scattering is sampled but also energy loss fluctuations. Unfortunately, if number of simulation steps is significantly different we may observe different mean energy deposition and/or RMS of energy deposition. All this is due to property of the model of fluctuations, which work not ideally for very small step size of a track. We still do not achieve independence of results on the threshold energy

3

Hi
Thank you very much for your explanation. I want to study the e- scattering process of atoms within the crystal. Should I use the DWPACoulombScattering model?

4

Hello,

bot models of Geant4 do not consider the state of the media. So, bot are approximate within a crystal. We recently have development of modified EM physics within crystals. Is it close to your task?

VI

5

Hi,

This task would apply to me, could you explain how to use this EM physics modification, as I am looking at implantation of low energy ions into crystals.

Thanks!