Re: (n,gamma) interaction

From: Paola Sala <paola.sala_at_mi.infn.it>
Date: Fri, 22 Jul 2011 22:22:37 +0200 (CEST)

Hello
I would suggest to check first of all in the output file,
where you have the number of inelastic interactions for each particle
type, and see whether you have photonuclear or not.
The way you are checking the primary type in the MDSTCK routine is very
dangerous, and I am not sure at all that it works. First of all, the stack
variables are overwritten at each interaction. Moreover, the
electromagnetic part has its own stack, partially independent from the
hadronic one. It would be much easier to rely on the J0TRCK variable in
the TRACKR common, and access it from the routines that are more intended
for scoring, like the USDRAW entry in the mgdraw routine.
Ciao
Paola

>
> Good day Vasilis and all fluka users.
>
> All your responses helped me a lot. And I am finaly starting to understand
> (a bit more) how powerful this tool, but i am once again quire your help.
> I am trying to count Gamma-n interactions while bombarding few bodies with
> electrons. I used the following input file :
> *
> * Created: 27.3.2011
> * At: 19:6:33
> TITLE
> MC-CAD Test
> GLOBAL 1.0 1.0
> DEFAULTS
> PRECISIO
> BEAM -.05
> ELECTRON
> BEAMPOS -0.4 20.0 20.0 1.0 0.0
> *DISCARD ELECTRON POSITRON PION+ PION-
> *PART-THR 0.02 NEUTRON 0.0
> *PART-THR -0.01 PROTON 0.0
> PHOTONUC 1. LEAD
> GEOBEGIN
> COMBNAME
> 0 0 MC-CAD
> * 1
> RPP B1 -50.0 50.0 -20. 80.0 -20.0 80.
> * 2
> RCC B2 0.0 20.00 20.00 0.04 0.00 0.0 0.06
> * 3
> RCC B3 0.04 20.00 20.0 0.10 0.00 0.0 0.06
> * 4
> RCC B4 0.14 20.00 20.0 0.10 0.00 0.00 0.06
> * 5
> RCC B5 -0.01 20.00 20.00 0.27 0.00 -0.00 0.16
> * 6
> RCC B6 -1.10 20.00 20.00 3.0 0.00 0.00 0.30
> END
> * 1; assigned material: Blackhole; mat # (1)
> R1 5 +B1-B6
> * 2; assigned material: Tantalum; mat # (18)
> R2 5 +B2
> * 3; assigned material: M100; mat # (34)
> R3 5 +B3
> * 4; assigned material: M100; mat # (34)
> R4 5 +B4
> * 5; assigned material: water; mat # (3)
> R5 5 +B5-B2-B3 -B4
> * 6; assigned material: air; mat # (8)
> R6 5 +B6-B5
> END
> GEOEND
> * 104 Air dry (near sea level)
> *
> MATERIAL .00120484 AIR
> COMPOUND -1.248E-4 CARBON -.755267 NITROGEN -.231781 OXYGENAIR
> COMPOUND -0.012827 ARGON AIR
> * 276 Water liquid H2_O
> * Chemical Formula: H -- O -- H
> MATERIAL 1.0
> WATER
> COMPOUND 2.0 HYDROGEN 1.0 OXYGEN
> WATER
> *MATERIAL 42. 100. 10.22 MOLYBDEN
> 100.Mo100
> MATERIAL 42. 95.94 10.22
> MOLYBDEN
> MAT-PROP 424.0 MOLYBDEN
> MAT-PROP 75.0 WATER
> STERNHEI 3.5017 .24 2.8004 .09116 3.4773
> WATER
> ASSIGNMA BLCKHOLE R1
> ASSIGNMA TANTALUM R2
> ASSIGNMA MOLYBDEN R3
> ASSIGNMA MOLYBDEN R4
> ASSIGNMA WATER R5
> ASSIGNMA AIR R6
> LAM-BIAS 0.0 0.02 LEAD PHOTON
> USERDUMP 100. 50. 0.0 dump
> RANDOMIZ 1.0
> START 10000. 0.0
> STOP
>
> and following subroutine ,kindly provided by Vasislis:
>
> SUBROUTINE MDSTCK ( IFLAG, NPSECN )
>
> INCLUDE '(DBLPRC)'
> INCLUDE '(DIMPAR)'
> INCLUDE '(IOUNIT)'
> *
> *----------------------------------------------------------------------*
> * *
> * Copyright (C) 1998-2007 by Alfredo Ferrari & Paola Sala *
> * All Rights Reserved. *
> * *
> * *
> * Created on 19 may 1998 by Alfredo Ferrari & Paola Sala *
> * Infn - Milan *
> * *
> * Last change on 18-jan-07 by Alfredo Ferrari *
> * *
> * *
> * Iflag = 1: standard Kaskad call *
> * = 2: Kaskad call after elastic (but hydrogen) *
> * = 3: Kasneu call *
> * = 4: Emfsco call *
> * *
> *----------------------------------------------------------------------*
> *
> INCLUDE '(EMFSTK)'
> INCLUDE '(FHEAVY)'
> INCLUDE '(FLKSTK)'
> INCLUDE '(GENSTK)'
> INCLUDE '(TRACKR)'
>
> LOGICAL LFIRST
> * Peak the last removed particle from the stack
> IF (ILOFLK(NPFLKA+1) .EQ. 7) THEN
> * Scan the secondary stack
> LFIRST = .TRUE.
> DO I=1,NP,1
> * Do we have a neutron there
> IF (KPART(I).EQ.8) THEN
> IF (LFIRST) THEN DO
> LFIRST = .FALSE.
> PRINT *,'Photonnuclear: E=',TKEFLK(NPFLKA+1)
> PRINT *,' Weight=',WTFLK(NPFLKA+1)
> PRINT *,'
> Pos=',XFLK(NPFLKA+1),YFLK(NPFLKA+1),ZFLK(NPFLKA+1)
> END IF
> PRINT *,' neutron E=',TKI(I), ' wgt=',WEI(I)
> END IF
> END DO
> END IF
> *
> RETURN
> *=== End of subroutine Mdstck =========================================*
> END
>
> I have simulated 5 cycles 100000 histories each but saw no Gamma-n
> interaction, and due to the calculations there are suppose to be at
> least few of them.
> Please advise, what could be the problem .
>
> Thank you in advance,
> Julian
>
>

Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
Received on Sun Jul 24 2011 - 15:50:50 CEST

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