Using fluence of HEHAD-EQ and THNEU-EQ in source_newgen.f

Dear FLUKA experts,
I have a question about the source_newgen.f user routine.

For the purpose of single event upset rate calculation in components of an electronics system in the irradiation room of a hadrontherapy facility, I implemented these components in the inside of a rack in a model of the IR using FLUKA. A 250MeV proton beam is shot at an angle of 60° at a 15mm thick steel plate which results in a radiation field of secondary particles inside this electronics rack, which is located slightly off-center of the beamline.

To calculate the SEU rate I need the HEHAD-EQ and THNEU-EQ fluence in these components. Since the components are very small compared to the dimensions of the irradiation room, a large number of primary particles would have to be simulated for a small error.
In order to get the simulation time down, my approach would have been to score the HEHAD-EQ and THNEU-EQ fluence at the outer shell of the rack and use these fluences as a source with the source_newgen.f for an in-detail simulation.

As I have never used it before, I would like to ask how I should setup the user routine.
Thanks in advance.

Dear @lukpblr,

Unfortunately, HEHAD-EQ and THNEU-EQ can only be used for scoring purposes and not as source particles.
I would suggest to have a look at the lecture on electromagnetic production and transport thresholds and to the biasing lecture from the last FLUKA course.
From the first one, you could see that probably you could increase the thresholds and then reduce the time spent transporting the electromagnetic component which is not relevant for your problem.
From the latter, you could learn how to “enhance” the components (hadrons and neutrons) you are interested in.

Thank you for your answer, I will look into the provided material.