PHYSICS cards question

[20244220042 (keying zhu)]

Dear experts,
Recently, while organizing my simulation results, I observed a decline in the outcomes at 150 MeV. I believe such a drop should not occur under normal circumstances.

To investigate this, I reviewed other FLUKA simulations （http://dx.doi.org/10.1103/PhysRevC.102.044613), which confirmed that no decline should appear at 150 MeV.

Additionally, I referenced results from forum experts (https://fluka-forum.web.cern.ch/t/ac225-and-ac227-cross-sections-for-proton-beam-on-th232-target/5059/4), which also showed no drop at 150 MeV.

Therefore, I concluded that there is an issue in my simulation.When I was searching for similar issues on the forum, I came across this post discussing model transition. How to use the RQMD model below 150 MeV/n?:

@lichen

I have another question. When calculating the cross-section of 225Ra and 223Ra produced by ion bombardment of a uranium target, I noticed a sudden change in the data at 150 MeV/n, which is clearly due to the model transition. Therefore, below 150 MeV/n, I would like to use the RQMD model entirely to compare the differences with the BME model.

1. I would like to use the RQMD model entirely to compare the differences with the BME model. I added PHYSICS cards( SDUM= DPMTHRES and BME-RQMD) according to the manual, but it doesn’t seem to work. Here are my input card and file.
   

   
   
   150.inp (2.0 KB)
   150_23_sum.lis (59.6 KB)
   150_24_sum.lis (40.5 KB)

2. I would like to use the BME model entirely to compare the differences with the RQMD model. I added PHYSICS cards( SDUM= DPMTHRES and BME-RQMD) according to the manual, but it doesn’t seem to work.
   

   
   
   150 .inp (2.0 KB)
   150_23_sum.lis (59.6 KB)
   150_24_sum.lis (40.5 KB)

Can you explain the cause of this issue? Thank you!！

[ceruttif (Francesco Cerutti)]

BME and RQMD have nothing to do with proton induced reactions, they apply to ion projectiles only (A>2 and A>1, respectively).
The unexpected dip you observe at 150 MeV might be due to a statistical fluctuation, which you are unable to judge since you forgot the RANDOMIZe card and so obtained (meaningless) zero statistical errors. By the way, the latest release, which every user is strongly encouraged to move to, henceforth prevents this issue (read the release notes).