Recommended Physics List for Heavy Ion Fragmentation

Physics Lists
1

Hello,

I am looking to simulate the nuclear fragmentation reactions that occur when a heavy ion beam (64Ni) hits a heavy target (Al).

I looked through the physics list guide: Physics List Guide — PhysicsListGuide 10.7 documentation and implemented a modular physics including: EmStandardPhysicsWVI, EmExtraPhysics, DecayPhyics, HadronElasticPhysics, HadronPhysicsQGSP_BERT, StoppingPhyics and IonPhysics

This seems to give me accurate stopping powers and angular scatterings from the target but the proportions of single proton and single neutron knock outs (reactions producing 63Ni and 63Co) are completely wrong.

Can anyone recommend a physics list or model that might be good for accurately reproducing these sorts of reactions for ions this heavy? Everything I’ve found on the subject talks about medical physics applications with projectiles only as heavy as Carbon or Oxygen.

Best,
Michael

2

Dear Michael,

I agree there is no much with your specific heavy ion beam and target. I would suggest to try both QMD and Binary ion cascade model. Please look at this paper for reference for the fragmentation models: Report on G4‐Med, a Geant4 benchmarking system for medical physics applications developed by the Geant4 Medical Simulation Benchmarking Group - Arce - 2021 - Medical Physics - Wiley Online Library

Then, you may look at this paper: ShieldSquare Captcha

Cheers
Susanna

3

Dear Susanna,

Thanks for your response, I’ll try implementing these two models and get back to you.

Cheers,
Michael

4

Dear all,

I implemented two cases, one where I tried adding QMD to a modular physics list and another adding BIC using the following lines respectively:
physicslist->RegisterPhysics(new G4IonQMDPhysics())
and then in another simulation
physicslist->RegisterPhysics(new G4IonBinaryCascadePhysics())

When I simulate a 64Ni beam at 250Mev/u incident on a 1975 mg/cm2 aluminium target in geant4:
The fraction of 64Ni that survive the target is 0.901,
64Co are produced at a rate of 2e-5.,
62Ni are produced at a rate of 1.06e-4,

When there numbers are compared to the rates I get in LISE++ (which I’m using as a control to validate the geant4 simulation) http://lise.nscl.msu.edu/lise.html:
0.89 64Ni should survive the target,
64Co should be produced at a rate of 6.87e-4
62Ni should be produced at a rate of 2.35e-3

With the exception of the 64Ni, it seems the reaction rates are off by an order of magnitude.

I notice that both QMD and BIC produce reaction products at identical rates, is there something wrong with the way I’ve added them to the physics list? Otherwise I can only conclude the models currently available aren’t accurate enough for the nuclei I’m trying to study.

Best,
Michael

5

Here, a run of example Hadr06 :
the macro, the appropriate lines extracted from the printout, and PhysicsList.cc

Cheers, Michel

arms.mac.txt (316 Bytes)
arms.out.txt (1.6 KB)
PhysicsList.cc.txt (2.8 KB)

6

Dear Michel,

Thanks for your help, I implemented the physics list available in the hadr06 extended example and the reaction rates are much better!

Thanks!
Michael

7

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