RE: (n,gamma) interaction

Dear Julian,

there is no direct solution to identify the reaction, however by inspecting
  the particles stack you can find out if a photon pushes neutrons (after a
photonuclear reaction). The way I found was to use the routine MDSTCK,
which is called just after an interaction and before pushing the
secondaries in the main FLUKA stack (FLKSTK).
Note the particle that made the interaction is removed from the stack,
actually only the stack pointer NPFLKA is decreased, and all its
information is found in the main stack with pointer NPFLKA+1

Therefore you inspect the if the "last" particle (NPFLKA+1) in the stack
to check if it was a photon ILOFLK(NPFLKA+1)=7
and scan the secondary particles from (GENSTK) if any of the them
KPART(#)==8 is a neutron

       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 =3D .TRUE.
          DO I=3D1,NP,1
* Do we have a neutron there
             IF (KPART(I).EQ.8) THEN
                 IF (LFIRST) THEN DO
                     LFIRST =3D .FALSE.
                     PRINT *,'Photonnuclear: E=',TKEFLK(NPFLKA+1)
                     PRINT *,' Weight=3D',WTFLK(NPFLKA+1)
                     PRINT *,' Pos=3D',XFLK(NPFLKA+1),
      & YFLK(NPFLKA+1),
      & ZFLK(NPFLKA+1)
                 END IF
                 PRINT *,' neutron E=3D',TKI(I), ' wgt=',WEI(I)
             END IF
          END DO
       END IF
*
       RETURN
*=== End of subroutine Mdstck
       END

Vasilis Vlachoudis
Dep EN, CERN
CH-1211 GENEVA 23
SWITZERLAND

Phone: +41-22 767 9851
GSM: +41-76 487 4378
Fax: +41-22 766 9644
Received on Thu May 19 2011 - 00:43:58 CEST