From: Rohe Daniela (Daniela.Rohe@psi.ch)
Date: Sat Oct 21 2006 - 00:56:22 CEST
Dear Fluka users and authors,
I am trying to get the residual nuclei from a natural carbon target
(12C, 13C) when bombarded with 590 MeV protons. There are two processes going
on. Spallation from direct proton process (RESNUCLE 1.0...) and low energy neutron processes (RESNUCLE 2.0 ...). Natural Carbon is marked in the low-neutron library to produce residuals.
Spallation which produces the low Z istotopes (e.g. 3H), gives reasonable results (compared to measurements). But the contribution from low energy neutrons is almost neglible. In particular I am missing the production of 14C from 13C(n,gamma)14C. I compared the distribution of neutrons from the track-length estimator with MCNPX and the results agree within a factor of 2. As a trial I also shoot neutrons (thermal ones and 4 MeV using DEFAULT NEUTRONS) directly onto the target and got no residual nuclei at all. As another trial I chose pure 13C (using the low neutron cross sections for natural carbon) but there was no change.
I am a new user and would appreciate any help. The input file is attached and you see also some options which are commented out and which I tried already but without improving the situation.
Best regards
Daniela Rohe
PSI
Switzerland
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
TITLE
Residual nuclei/activation of carbon by protons
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
DEFAULTS HADROTHE
BEAM -590.E-03 PROTON
BEAMPOS 0.0 0.0 -50.0
*
* LOW-NEUT 72.0 22.0 0.0196 1.0 1.0 -11.0
*
PHYSICS 3.0 EVAPORAT
PHYSICS 1.0 COALESCE
*
EVENTYPE 0.0 0.0 2.0 0.0 0.0 0.0DPMJET
*
GEOBEGIN COMBNAME
0 0 A simple C 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 -10.0 +10.0 -10.0 +10.0 0.0 +6.0
* plane to separate the upstream and downstream part of the target
* XYP body4 3.0
END
* black hole
regBH1 5 +body1 -body2
* vacuum around
regVA2 5 +body2 -body3
* C target
regBE3 5 +body3
* C target 2nd half
* regBE4 6 +body3 -body4
END
GEOEND
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
MATERIAL 6.0 12.011 1.750 6.0 0.0 0.0CARBON
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
* C target, 1st and 2nd half
ASSIGNMAT CARBON regBE3
* External Black Hole
ASSIGNMAT BLCKHOLE regBH1
* Vacuum
ASSIGNMAT VACUUM regVA2
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
* EMF EMF-OFF
* e+e- at 1 GeV, gamma production threshold set at 100 eV
EMFCUT -1.0 100E-09 0.0 CARBON PROD-CUT
* EMFCUT -1.0 100E-06 1022 2.0 3.0 1.0
*
* LOW-BIAS 73.0 73.0 0.95 3.0 3.0 1.0
*
* USERWEIG 0.0 0.0 0.0 0.0 0.0 1.0
*
IRRPROFI 9.3226E+07 9.594E+14
DCYTIMES 1.0 2.388E+08 3.746E+08
RADDECAY 1.0 1.0 1.0 ! 000000010. 0.0 200.0 1.0
*
DCYSCORE 1.0 0.0 0.0 1.0 3.0 1.0RESNUCLE
DCYSCORE 2.0 0.0 0.0 4.0 4.0 1.0RESNUCLE
DCYSCORE 3.0 0.0 0.0 5.0 5.0 1.0RESNUCLE
* 1. cooling time
RESNUCLE 1.0 -41.0 6.0 20.0 regBE3 2400.0spall
RESNUCLE 2.0 -42.0 6.0 20.0 regBE3 2400.0neut
RESNUCLE 3.0 -43.0 6.0 20.0 regBE3 2400.0all
* 2. cooling time
RESNUCLE 3.0 -44.0 6.0 20.0 regBE3 2400.0medi
* 3. cooling time
RESNUCLE 3.0 -45.0 6.0 20.0 regBE3 2400.0cool
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
* Cartesian binning of the deposited energy inside the target
* Dosis via COMSCW
* 2. cooling time
* DCYSCORE 2.0 0.0 0.0 1.0 1.0 1.0USRBIN
* USRBIN 10.0 208.0 -50.0 10.0 10.0 6.0dosis
* USRBIN -10.0 -10.0 0.0 1.0 1.0 6.0 &
* activation Bq/g
* 2. cooling time
* DCYSCORE 2.0 0.0 0.0 6.0 6.0 1.0USRBIN
* USRBIN 10.0 235.0 -51.0 10.0 10.0 6.0activ
* USRBIN -10.0 -10.0 0.0 1.0 1.0 6.0 &
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
* 1.: particle, 2.: angle
USRYIELD 1422.0 201.0 -61.0 -1.0 -2.0 1.0ALL
USRYIELD 14.5 0.5 14.03.14159265 0.0 3.0 &
* 1.: energy, 2.: angle for neutrons
USRYIELD 1401.0 8.0 -62.0 -1.0 -2.0 1.0ALL
USRYIELD 0.020 0.001 20.03.14159265 0. 3. &
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
USRTRACK -1.0 8.0 -63.0 3.0 2400.0 40.0npart
USRTRACK 0.020 1.0E-06 0.0 0.0 0.0 0.0 &
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
RANDOMIZE 1.0
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
START 10000000.0
STOP
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