Running errors: Abort called from DEUSEV reason NP/=0 before NUCEAZ

Dear FLUKA experts,

I tried to run FLUKA with the following settings

  1. redefined a material HYDROGEN with high density (0.6 g/cm3) as the target
  2. incident particles are 12C
  3. using LAM-BIAS to consider only inelastic nuclear interactions

However, if I set the kinetic energy of 12C to 0.01 GeV, and consider 10000 incident particles, errors occurred, shown as

Abort called from DEUSEV reason NP/=0 before NUCEAZ. Run stopped!
STOP NP/=0 before NUCEAZ.

But no errors when I changed the incident particle number to 1000 with 0.01GeV.
ALso, no no errors when I changed the incident particle number to 10000 with 0.1GeV.

I have attached the inp file.
Anyone knows what happened?

Best regards,
Kaiwen Li

run.inp (1.5 KB)

Anyone can help me?
Thanks in advance!

Dear Kaiwen Li,

We are looking into it. It is a legitimate bug (12C picking 2H as target isotope, going to inverse kinematics, and doing a 2H on 12C interaction which crashes). Further tests are now underway. Stay tuned.

With kind regards,


Dear Cesc,

Thanks a lot for your response! Looking forward to your results.

One more question, in the above situation (C-H inelastic nuclear interaction, 0.01GeV for 12C), the ratio of the produced alpha particle is about 0.89 per reaction. However, when I used Geant4 to simulate the same interaction, the ratio of alpha particle is 0.
Does it come from the physics model difference?

Best regards,

Dear @kwlibuaa,
I believe that with the new Fluka release your problem should have been fixed.

Dear amario,

That’s great!
Thanks a lot!