Photo-produced muons near beam energy biasing

Advanced Features and User Routines
1

Dear FLUKA experts,
I am running simulations where I send an electron beam into a thick aluminum target to obtain photo-produced muons near beam energy, sampling them on a surface ~1m around the target.

I am biasing the interaction length of the photons by 10^-5 to produce more muons. Moreover, as I am interested in higher-energy muons, I am also using leading particle bias to reduce CPU time.

I also did the following to stretch the spectrum of the muons produced:

  • Simulating 10^8 primaries, in this way I get good statistics of muons up to ~9.6 GeV.
  • Make a new simulation increasing all energy cuts to 9.6 GeV and stopping everything after my sampling surface.
  • With this, I greatly reduce the average time needed to simulate a primary, and I am able to simulate 10^11/10^12 electrons and get muons up to ~10.4 GeV
  • “Stich” the two results together.

However, repeating this process and increasing the energy cuts to 10.4 GeV does not help because the average time needed to simulate a primary does not change much. Also, increasing the number of primaries and/or the biasing to the interaction length makes the simulation time too big.

So, I wanted to ask if you know/can suggest some other method/technique to increase the number of muons with energy close to the beam without exponentially increasing the simulation time.

3

Which is your electron beam energy (and Al target thickness)?
I’m afraid that the high-cut technique you devised is already the best suited to your purpose, since the biasing of the interaction outcome, favouring the production of highest energy muons, is not an available option.

4

Thank you for the answer.

I’m sorry, I thought I wrote it.

The electron energy is 11 GeV (momentum) and the Al target is ~4 meters long (in the beam direction).