|Message: Re: structure of GEANT4 data files (cold neutrons on LH2 target)||Not Logged In (login)|
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> Is there any documentation on that?
Unfortunately, the answer is no.
> I need to understand this structure because I would like to change > this data file. I would like to have cross section file for a particular > mixture of para- and ortho-hydrogen. If I am interested just in neutrons > in 1-100 meV range, should I just replace a few top lines in all 3 sections?
I do not think so. The data is only for free gas model. And your material and temperature indicate that you must use specific thermal scattering files data. The data for para- and orhto- hydrogen are in G4NDL4.0, but they cannot be used even in G4 v9.5. (Some further developments are required. )
> The next question: how does the GEANT4 cross section depend on temperature > and pressure of material? > > For example, I set my target material to be > new G4Material("H2Liq" , z= 1, a= 1.01*g/mole, density= 70.8*mg/cm3, kStateLiquid, temperature=20*kelvin, pressure=1.5*atmosphere); > > Will changing the temperature and pressure change the cross sections GEANT4 uses?
Yes, it will. But it is only for temperature. We do not take into account PV relationship even in a material in gas state.
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