Good day.
I wanted to calculate a simple task: the reaction of alpha particles (energy 2.1 MeV) with a beryllium (9Be) target (thickness 1 mm), with the registration of emitted gamma quanta. This experiment was conducted on a cyclotron. As expected, the reaction should proceed through the birth of unstable 13C* and its decay into 12C either with the emission of a neutron (energy 5.5-7.7 MeV), or 12C* with the emission of a neutron (1.8-3.2 MeV) and a gamma quantum of 4.44 MeV.
However, as a result of the modeling, I see the following picture for one event: gamma 4.44 MeV, gamma ~2.6 MeV and neuton < 0.5 MeV (see screenshot).
I tried to use QBBC, QGSP_BIC_HP and Shielding physicsList.
Thank you for your answer!
I downloaded G4TENDL from the Geant4 download page, set the environment variable like:
export G4PARTICLEHPDATA=/your/path/G4TENDL1.3.2/
and after this used this physics list:
G4VModularPhysicsList* physicsList = new QGSP_BIC_AllHP();
physicsList->RegisterPhysics(new G4RadioactiveDecayPhysics);
But now I dont see 4.44 MeV gamma at all Looks like de-exitation C12* dont work, or I don`t know.
I compiled the Hadr03 example and ran the macro file you sent, the results were different (see the picture). I also tried to copy PhysicsList to my project from this example, and the results were wrong.
As far as I understand (correct me if I’m wrong), this is because I’m using an old version of Geant4, since my example Hadr03 does not have G4IonPhysicsXS and Geant don`t understand what is it, is this true?
Basically, you can’t create gammas from that reaction in a correct propoetion unless you fix the neutrons. Paper about this will be out soon (December-ish)
Sorry for bothering you again, but apparently I was too happy too soon.
I started looking at the yield of gamma quanta 4.44 (the first level of C12 excitation) and 3.21 MeV (the second level of C12 excitation) depending on the energies of the incident alpha particles and got something very strange, completely unlike what would be expected according to the reaction cross-sections.
For example, for an alpha particle with an energy of 2.1 MeV, ~75e3 gamma quanta of 4.44 MeV are generated per 1e5 incident alpha particles, while at an alpha energy of 2.4 MeV, only neutrons are generated in the simulation.
I don’t know what the reason for this behavior is?
Good day, very interesting remark. I will wait your aricle.
Please tell me, is the problem you found related to mine (see the last message) ?
Because I don’t understand what to do, I’ve already tried to switch to other libraries (G4ParticleHP
packages), but it also doesn’t work (most likely I’m doing it wrong)…
After rebuilding Geant4 with the particleHP module and TENDL libraries, the simulation yielded results consistent with analytical predictions (across the entire range of incident alpha particle energies)!
G4IonPhysicsXS is also necessary to simulate the process of de-excitation of the carbon nucleus.
