[fluka-discuss]:

From: Doo Jin Kim <doojin.kim_at_cern.ch>
Date: Mon, 7 Oct 2019 19:38:11 +0000

Dear Fluka Users,



I wanted to study meson (e.g., pions) production in beam-dump type experiments.

As a simple exercise, I created the following input card and executed a run.



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

BEAM 400.E+00 PROTON
BEAMPOS 0.0 0.0 -10.0
*
GEOBEGIN COMBNAME
  0 0 A simple Be target inside vacuum
RPP body1 -5000000.0 +5000000.0 -5000000.0 +5000000.0 -5000000.0 +5000000.0
RPP body2 -1000000.0 +1000000.0 -1000000.0 +1000000.0 -100.0 +1000000.0
RPP body3 -27.0 +27.0 -9.5 +9.5 0.0 +210.0
* plane to separate the upstream and downstream part of the target
XYP body4 209.5
END
* black hole
regBH1 5 +body1 -body2
* vacuum around
regVA2 5 +body2 -body3
* Hg target 1st half
regBE3 5 +body3 +body4
* Hg target 2nd half
regBE4 5 +body3 -body4
END
GEOEND
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
MATERIAL 80.0 13.546 16.0 MERCURY
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
* Be target, 1st and 2nd half
ASSIGNMAT BERYLLIU regBE3 regBE4
* External Black Hole
ASSIGNMAT BLCKHOLE regBH1
* Vacuum
ASSIGNMAT VACUUM regVA2
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
* e+e- and gamma production threshold set at 10 MeV
EMFCUT -0.010 0.010 1.0 MERCURY PROD-CUT
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
* pi+ pi- pi0 cuts
PART-THR -0.0 13.0 16.0 0.0 0.0 1.0
PART-THR -0.0 23.0 24.0 0.0 0.0 0.0

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



Then I looked at Number of stars generated per beam particle in a .out file.



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

 Number of stars generated per beam particle:
 Prompt radiation Radioactive decays
   2.3050E+02 (100.%) 0.0000E+00 (100.%)
   ...
   4.2503E+01 (18.4%) 0.0000E+00 ( 0.0%) generated by PION+
   5.8008E+01 (25.2%) 0.0000E+00 ( 0.0%) generated by PION-

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



As shown above, 40 - 60 pions were created per proton. However, I actually expected 4 - 5 pions per proton for a 400 GeV proton beam. Did I do wrong simulation or did I misinterpretate the output?



I'm waiting for your advice/suggestions.



Thank you,

Doojin


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Received on Mon Oct 07 2019 - 22:40:33 CEST

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