I’m a first time Fluka user and I need some guidance on scoring secondary particle information. I’m simulating a simple setup of an electron beam incident on a tungsten target. In this setup, I’m interested in scoring the position and momenta of the K+ K- pairs created from the photoproduction and subsequent decay of phi mesons.
In my attached input card tut1.inp (1.2 KB)
, I’ve enabled photonuclear interactions and applied biasing. By Scoring Kaons± with USRBIN, I’m able to see that the K+ K- pairs are being produced. I understand that I need to edit USDRAW in mgdraw.f in order to score the positions and momenta of the K+ K- pairs. Is there any material that explains how I can modify mgdraw, step-by-step, in order to obtain my desired output?
sorry for the delay. There is of course good material to teach you how to use mgdraw and other advanced FLUKA routines. The most relevant would be the advanced workshop offered a few years back, for which all the material is freely available here: .
For your specific scenario, I would pay particular attention to: background: module 2 and module 3, providing an overview of the fluka user routines, as well as some fortran basics (needed since mgdraw will need to be written in fortran) implementation: module 10 is the most relevant here, and I highly encourage you to look over the associated exercise, which you can find here under the section “User Routines II (MGDRAW): exercise”, see the attachments for that section.
I believe with this information, especially the exercise and its solution that could provide a backbone for the USRDRAW entry you want to write, you will be able to score secondary kaons as you intend.
Thank you for your helpful response. I’ll be doing a deep dive into the advanced workshop that you shared.
In the meanwhile I’d like to ask one more question that is related to my original post but perhaps not related to scoring. I checked the .out files using the viewer function in flair and I noticed that although charged kaons are being produced in the simulation, the number of charged kaon decay products per beam particle is 0, see the screenshot below:
Unstable particle decay is included by default, with no need for an additional card.
Charged kaon decay products are mostly muons, neutrinos, pions, positrons/electrons (and not charged kaons themselves), which you can actually find in the above list.
I apologize, I think my previous comment was poorly written. The process I’m interested in is phi → K+ K-, which I believe is included in Fluka. I can see the K+ K- are being produced in the simulation. I became puzzled once I realized that the K+ K- were not listed as decay products when I check the .out file because I am expecting K+ K- to be the decay products of phi.
Sorry, it was my misunderstanding, your mention of decay of phi mesons was actually clear.
In the above list, you can find only the decay products of transported particles, for which decay is an independent process in the course of their transport.
On the contrary, the decay products of very short-lived particles - not transported but decaying at production - appear as secondary particles generated in the inelastic interaction that went through the very short-live particle temporary production.
