How to specify the elements(Ge76, Ge74 and Ge73)

I want to find the elements(Ge76, Ge74 and Ge73). But the only thing I could find was like as following:
“G4Element* Ge = new G4Element(“Germanium” ,“Ge”, 32, 72.61*g/mole);”
I do not know how to specify the above elements. Would you please help me ? Thank you very much for kind help :grin:

Best wishes

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You’re asking about isotopes, not elements. If you want to use them to create a custom material (enriched germanium, or something similar), instantiate them as G4Isotope instances and build your material from there. See the Geant4 documentation for materials.

If you are looking for nuclear tracks (e.g., interaction secondaries, or beam particles), you would look for a G4Ions with the appropriate A and Z values. See the Geant4 documentation for particles.


see example TestEm3:

Thank you very much for your kind help :grin:
The advice you offered was really great!
Wish you have a nice day :laughing:

The example you offered was really detailed and helpful :grin:
Thank you very much for helping me!
Wish you have a nice day :smile:

I take the occasion to ask something very related to this: quoting from the Geant4 user manual:

Using the internal Geant4 database, a G4Element can be accessed by atomic number or by atomic symbol (“Al”, “Fe”, “Pb”…). In that case G4Element will be found from the list of existing elements or will be constructed using data from the Geant4 database, which is derived from the NIST database of elements and isotope compositions. Thus, the natural isotope composition can be built by default. The same element can be created as using the NIST database with the natural composition of isotopes and from scratch in user code with user defined isotope composition.

I understand that a G4Element (e.g. Ge-76) should be provided by default with the list of its natural isotopes and relative abundances. Is this really true? I cannot find the definition of default isotopical natural abundances in the Geant4 source code. Can anyone please clarify this or point me to the source code location?

Or does this just mean that quantities like the density are computed taking into account natural isotopic abundances?

First, “Ge-76” is not an element. It is an isotope. You would have to define it yourself if you want to use it directly, or if you want to create your own special “enriched germanium” element and material.

For natural abundances, we use the NIST database by way of the G4NistManager factory class. If you want to get the germanium element with the natural abundances predefined, use G4NistManager::Instance()->FindOrBuildElement(32).

if you want natural germanium as a material, e.g. to create a nice germanium crystal volume, use G4Nistmanager::Instance()->FindOrBuildMaterial("G4_Ge").

First, “Ge-76” is not an element. It is an isotope.

Oups, typo!

So even G4Nistmanager::Instance()->FindOrBuildMaterial("G4_Ge") returns a germanium material with natural abundances predefined? Cool!

Could you please point me to the section of Geant4 source code where this is actually done? I am curious to see.

Thank you for the clarifications!

Nevermind, I found what I was looking for: