Can't produce metastable Tc99 with use of Bertini Cascade model

Physics Processes, Models and Cross Sections
1

Hello,
I work on Mo100(p, x)Y nuclear reaction modeling.
The goal is to investigate Tc99m production.
I’m using a custom physics list which includes Bertini cascade and Pre-Compound model.
The problem is that I don’t get any metastable state of Technetium, only ground state Tc99.
There was no such problem when I used Binary cascade + Pre-Compound model, but the production yield of Tc99m (Tc99[142.683]) was very small and didn’t correspond to an experimental result. So, I had to change the cascade model.

Is there any other option I could have probably forgotten to add or maybe any other way how to retrieve the excitation energy from a nucleus?

Thanks!

(There are a lot of isomeric states of other nuclei and G4RadioactiveDecay is registered)

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Hard to answer this without knowing which lists you are using specifically. And generally speaking, example physics lists will do much of the heavy lifting for you. For example, what about the Activation example? That is an example specifically concerned with hadronic cascades and tracking all subsequent radioactive decays.

I suspect you just modify/add from the lists it uses.

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Dear @jrellin,
I’m using a custom model to describe hadron inelastic processes (see
MolybdenumHadronInelasticPhysics.cc (4.9 KB)). I registered this physics as well as hadron elastic physics and others like radioactive decay and EM in my physics lists (
MolybdenumPhysicsListGeneral.cc (5.0 KB)).

In the first attached file (MolybdenumHadronInelasticPhysics.cc) I tried different models of hadronic intranuclear transport + de-excitation :

  1. Binary cascade + Pre-Compound gives me very small amount of Tc99m (Tc99[142.683]) nucleus produced; I spot the yield of Tc100 produced via (p, n) reaction is significantly greater than the yield of Tc99m via (p, 2n) channel. However, TENDL cross sections which I’m using suggest the opposite results (the number of Tc99m should be greater than Tc100). The produced activity of Tc99m is ten times less than a measured in a real bombardment of cyclotron target;
  2. INCL++ and Pre-Compound gives the same result as the previous one;
  3. Bertini cascade + Pre-Compound: no Tc99m states are produced, only Tc99 ground state. But the number of Tc99 is greater than Tc100 and it corresponds to the TENDL data;
  4. Only one model that yields the adequate proportions of Tc99m and Tc100 is QMD, but it increases the simulated yield of Tc99m two times compared to the experimental one.

I would like to have a reasonable yield of Tc99m to suite the experimental data.

4

Dear @jrellin,
I managed to produce a significant amount Tc99-m just changing the G4DeexPrecoParameters::SetDeexChannelsType to fGEM which enabled use of Generalized Evaporation model. Also, in FLUKA literature I found that for correct production of isomeric state de-excitation model should take into account spin and parity of products. This approach is implemented in the Hauser-Feshbach model. But, I guess both fEvaporation and fGEM models use Weisskopf-Ewing model to calculate residuals production, which is not suitable for isomeric states production.
The fGEM, as I also read in some literature, uses extended version of Weisskopf-Ewing model, but not the Hauser-Feshbach.

What do you think about that? Am I correct?

Sincerely, Ihor