Detect pion created from cosmic-ray

Dear Fluka Experts,

I want to scoring pi+ flux created from cosmic-ray showering.
So I make input file based on fluka GCR_allparticle example input.
Change parts are

  1. make a region represented Lithosphere below last air region
  2. add USRTRACK for detect pi+, and detect region set to @ALLREGS

I think this setup would allow me to evaluate the energy flux of the pi+ at any region I choose to track the particle. And if I enter the volume of the region I want to track in the options of USRTRACK, I think that it will calculate the flux per unit volume by dividing the total amount of flux by that volume.

Am I right?

Thank you for your help.

Dear @laplacian,

That’s correct in principle. Please note a few technical details that you might check, for example, at this post → GCR extended layers and scoring through mgdraw file - #3 by ainfanti

In particular, please note the normalization issue mentioned in the above post when creating new regions and request USRTRCKs.

Please note that in the screenshot you have posted it is indicated PION- while I understood you are interested in PION+. In addition, you should replace @ALLREGS with the name of the region attributed to the new Lithosphere layer (if specifically interested in this region).



Thank you for reply and good reference link Angelo :).

Actually, I interested in both PION+ & PION-. Attached image and my description are not equal. Sorry for the confusion.

I have an additional question that arises after looking at the sum.lis file. USRTRACK estimator get parameter about detector volume. In manual, default volume is 1 cm^3, If I add number, volume is that number.
but in sum.lis file, volume is not equal to value that I input.
Specifically, it is as follows.

  1. region:@ALLREGS, volume:1.0 → volume on sum.lis : 1.81029899E-19
  2. region:@ALLREGS, volume:8.16228E24 → volume on sum.lis : 1477616.75

In this step. vol 2 / vol 1 = 8.16228E24 exactly. In this moment I think there is some eigen unit volume proportional 1.81029899E-19.
But next step, I confused.

  1. region:Air001, volume:1.0 → volume on sum.lis : 143859.734

It is not equal to 1.

The fluka course I saw said that the estimator not measure the volume. So, input some volume in USRTRACK, it will be normalized to that volume. I think volume is not depend on region. But maybe it wasn’t. How to define volume on sum.lis ? And what kind of relationship between volume and region and volume on sum.lis works? I haven’t been able to find this in the fluka manual yet.

thanks regards.

Dear @laplacian ,

Are you using the NO-NORM option?
Could you please attach your input file? It is very difficult to debug the problem without it.



OK I attach my input card and sum.lis result. In this input file, I compared @ALLREG vs only one region and volume 1 cmc vs 1000 cmc.

Thanks regards.
005_track_24_sum.lis (65.9 KB)
005_track_01.inp (68.2 KB)

Dear @laplacian ,

I see you are not using the NO-NORM option. So that, FLUKA forces to apply the defaults normalization values for the standard atmosphere layers, which include their volumes (via the *.sur file).

I would suggest you to use the option NO-NORM (see link in my previous post). So that, you are in full control of the normalization factors applied to the scorings.
I made a quick test of your *.inp file with NO-NORM and the volume is properly reported in the sum.lis.



Thank you for your work Angelo :slight_smile:
I’ll take your advice and try it.
It really helped a lot. Thank you again.

Thanks regards.