Hi, I am trying to simulate a He-3 detector response and I am getting an unexpected spectrum. I am using QGSP_BIC_HP list with G4ThermalNeutrons. My material definitions are:
G4double z3, a2, density2, density3;
G4String name2, symbol2;
a2 = 3. * g/mole;
G4Element* elHe3 = new G4Element(name2="Helium3",symbol2= "He",z3= 2., a2);
density2 = 0.00033 * g/cm3;
G4Material* He3_det = new G4Material("He3_det", density2, ncomponents2= 1);
density3 = 0.00023 * g/cm3;
G4Material* He3_det1 = new G4Material("He3_det1", density3, ncomponents2= 1);
Can you please let me know what am I doing wrong.
The material definition looks OK (it looks like you have defined 2 and 1.5 atm of He3. The spectrum is not necessarily unexpected. It looks like a spectrum in a He3 ionization chamber when there are some gamma rays present and few to no neutrons. What is your geometry and what are your source parameters (particle types(s), number, energy, etc.)?
Respected Dr. McFee,
Thanks for your reply. I researched links on the previous forum changed my material as per the guidelines to below:
//// He-3 detector 1 material
G4int protons=2, neutrons=1, nucleons=protons+neutrons;
G4double atomicMass = 3.016*g/mole;
G4Isotope* he3 = new G4Isotope("He3", protons, nucleons, atomicMass);
G4Element* He3 = new G4Element("Helium3", "He3", 1);
G4double pressure = 1.51988*bar;
G4double temperature = 293*kelvin;
G4double molar_constant = CLHEP::Avogadro*CLHEP::k_Boltzmann; //from clhep
G4double Density = (atomicMass*pressure)/(temperature*molar_constant);
G4Material* Helium3 = new G4Material("Helium3", Density, 1, kStateGas, temperature, pressure);
This gave me the correct spectrum (Attached).
I guess my geometry was fine, there an issue with the way I defined my Materials.
Thanks very much!