USRBIN vs USERDUMP visualization inconsistency for low-energy alpha particles

Scoring
1

Dear FLUKA community,

I would like to ask for your advice regarding an issue I encountered.

I am running a simple simulation where I define a source routine emitting low-energy alpha particles, with the aim of having them enter a detector volume.

I am using a USRBIN to score, and the resulting plot clearly shows that all particles stop inside the detector, as expected.

In addition, I have included a USERDUMP, as I would like to visualize the particle trajectories. However, the USERDUMP visualization is not behaving as I anticipated:

  • In the USRBIN, the particles are seen to stop inside the detector.
  • In the USERDUMP, the trajectories appear as straight lines, passing through the detector without showing any interaction or stopping.

Userdump
Userdump2041×1014 574 KB

I am wondering whether I might be misunderstanding how the USERDUMP should be interpreted, or whether this behavior indicates some issue with my setup.

If anyone has encountered a similar situation or can provide some insight, I would greatly appreciate it.

Thank you in advance.

2

While the USRBIN plot is limited to the Y (third dimension) interval you specified, the USERDUMP plot has no filter along Y and so reflects the particle trajectories above and below the detector.