Hi. If I want to simulate radioactive decay in Geant4, What physics do I need to include?. Do I have to include both G4DecayPhysics and G4RadioactiveDecayPhysics (just like in Geant4 example B3)?, Or Do I only need to include one of them?. Thanks
Geant4 Version: 11.2.1
Operating System: Windows 10
Compiler/Version: Visual Studio 2022
CMake Version: 3.29.0-rc2
What does the documentation say?
Hi. I was reading Section 5.2.4 (Particle Decay Process) of the Geant4 Book For Application Developers, Release 11.2; This (Section 5.2.4) is information I hadn´t read before.
So far, I have only been able to read about G4DecayPhysics and G4RadioactiveDecayPhysics in the C++ code in:
C:\geant4-v11.2.1\geant4-v11.2.1-source\source\physics_lists\constructors\decay.
What I´m going to read next are the Geant4 examples (related to decay) and the Geant4 Physics Reference Manual (the Sections related to decay). Thanks
Hi. I already took a look at the Geant4 examples related to decay. These examples are Activation (in the radioactivedecay folder of the extended examples), rdecay01, rdecay02 and the basic example B3.
The physics list in the Activation example includes G4DecayPhysics and Radioactive Decay Physics.
The physics list in the rdecay01 example includes radioactive decay.
The physics list in the rdecay02 example includes decay and radioactive decay.
Regarding the basic example B3, the following is included in the physics list:
G4DecayPhysics: defines all particles and their decay processes
G4RadioactiveDecayPhysics: defines radioactive decay for Generic Ion
On the other hand, I’ve watched 2 Youtube videos(from the Youtube channel known as Physics Matters) that describe how to simulate radioactive decay in Geant4; those Youtube videos are:
Geant4 Tutorial 14: Simulating Radioactive Decays and Energy deposition
Geant4 Tutorial 7: Adding Radioactive Decay
Both videos include G4DecayPhysics and G4RadioactiveDecayPhysics.
The Video “Geant4 Tutorial 7: Adding Radioactive Decay” also describes a radioactive source of Fluorine 18.
So, I think that with the help of those Youtube videos I can simulate radioactive decay in Geant4; What is your opinion?
Have you actually tried running these examples or following the tutorials linked to?
Hi. I ran those examples in the past. The most recent thing I´ve done regarding those examples is looking at some C++ files and reading information about those examples. I think it would be a good time now to run those examples one more time. Regarding the 2 Geant4 video-tutorials that I mentioned, I watched them yesterday for the first time and I think they are good video-tutorials. What is your opinion / suggestions / recommendations?. Thanks
Have you tried actually doing these things? What is your goal? If you do the things you have learned, did they achieve your goal?
We cannot possibly tell you what to do; if you have specific, concrete questions (like “I tried to do X, and it did not do the Y that I expected.”) then these forums might be able to help.
If you are looking for a mentor to guide you through learning how to use Geant4, the forums are not the place for that.
Hi. Regarding the questions:
Have you tried actually doing these things? Answer: Yes. I have read the README.txt file of the Geant4 examples related to radioactive decay (Activation, B3, rdecay01 and rdecay02); I have also read the main.cc and PhysicsList.cc files of each of those examples. I have also run examples related to radioactive decay.
After reading the Geant4 documentation and watch the video tutorials on how add radioactive decay in Geant4 (from the Youtube channel known as Physics Matters), I still don´t understand why it´s necessary to include G4DecayPhysics and G4RadioactiveDecayPhysics to simulate radioactive decay in Geant4. That would be my main doubt / question so far.
What is your goal? Answer: My goal is to simulate a radioactive source (it could be Cobalt 60, Barium 133, Cesium 137, Europium 152 or Sodium 22) that emits gamma rays; I’m interested in the simulation of the interactions of those gamma rays with a scintillation detector (Thallium-activated Sodium Iodide).
If you do the things you have learned, did they achieve your goal? Answer: I’ve learned some things about Geant4, and that has helped me progress in my simulation, however I still have some doubts.
How do you recommend progressing in a Geant4 simulation?, With the help of a mentor in Geant4 would be the best option?. Thanks
Hello,
I still don´t understand why it´s necessary to include G4DecayPhysics and G4RadioactiveDecayPhysics to simulate radioactive decay in Geant4.
Because Geant4 is a versatile Toolkit that allows the user to include only the physics processes of interest or to exclude physical interactions that are not needed for the topic one wants to study to save computational power.
If you simulate electrons, then you dont have to include thermal neutron interactions.
So if you want to have Radioactive Decay in your simulation, then you have to include it.
How do you recommend progressing in a Geant4 simulation?
As mkelsey said: We cannot possibly tell you what to do.
If you tried things on your own, then run into a problem and have a specific question then these forums might be able to help.
But it is expected from you, that you put a fair amount of research into your own problem first and then phrase a question that shows you’ve tried things and you did research beforehand. Show that your question is more than a general thing, that one could google.
Do things and report results. Don’t hesitate changing code, toying around with the examples or your code. You cant break a thing (might want to have a backup). 
Hi. Thank you for your advices / recommendations. I’m going to keep them in mind, and from now on I’m going to put them into practice. On the other hand, regarding radioactive decay, I reread the Geant4 Physics Reference Manual where the following is mentioned:
“The decay of particles in flight and at rest is simulated by the G4Decay class“ (Chapter 4); “G4RadioactiveDecay and associated classes are used to simulate the decay, either in-flight or at rest, of radioactive nuclei…“ (Chapter 40).
After rereading that information I think I understand things better. I didn´t take into account that individual particles (like the muon, for example) can also decay, not just radioactive nuclei.
So, could the decay of particles (not radioactive nuclei) (like the muon, for example) be considered a type of radioactive decay?, or Could the decay of particles be considered a type of decay similar to the radioactive decay?. Thanks