Re: special beams in FLUKA

Hi Luis,

the problem you describe requires a user defined source-routine. As you
already mentioned, a good source of explanations can be found not only
in the manual but also in the respective course documentation, the
latest version being available at:

http://www.fluka.org/content/course/NEA/lectures/UserRoutines.pdf=20

To produce the concentric rings (elliptical) of source particles you'll
have to sample the particle positions accordingly (e.g., in X and Y).
What concerns the particle type, perhaps a quick trial how to do it
based on a cummulative sampling:

source.f:
---------

*
* first initialization
*
      DO 1 I=3D1,MAXUBP
         K =3D 2*I-1 + IWSHIFT
         IF ((WHASOU(K).GT.ZERZER).AND.(WHASOU(K+1).GE.ZERZER)) THEN
            NUBP =3D NUBP+1
            IDUBP(NUBP) =3D INT(WHASOU(K))
            FRCUBP(NUBP) =3D WHASOU(K+1)
            SUMFRC =3D SUMFRC+FRCUBP(NUBP)
         ENDIF
         SAMUBP(I) =3D ZERZER
 1 CONTINUE

....

*
* later in the sampling part
*
* sample/modify particle type
      SUMFRC =3D ZERZER
*
* use the FLUKA random number generator to sample the particle fraction
      FRAC =3D FLRNDM(0.0)
      DO 10 I=3D1,NUBP
* sampling cummulative particle type fractions
         SUMFRC =3D SUMFRC+FRCUBP(I)
         IF (FRAC.LE.SUMFRC) THEN
            ILOFLK(NPFLKA) =3D IDUBP(I)
            SAMUBP(I) =3D SAMUBP(I)+ONEONE
            NALL =3D NALL+1
            GOTO 11
         ENDIF
   10 CONTINUE
   11 CONTINUE

hope this helps, cheers

Markus

> -----Original Message-----
> From: owner-fluka-discuss_at_mi.infn.it [mailto:owner-fluka-
> discuss_at_mi.infn.it] On Behalf Of Fernandez-Hernando, JL (Juan)
> Sent: Mittwoch, 19. November 2008 15:54
> To: fluka-discuss_at_fluka.org
> Subject: special beams in FLUKA
>=20
> Dear all,
>=20
> I want to perform a few simulations with special beams and I was
> wondering
> if perhaps someone has already done this before and modified her/his
> source routine in a very similar way than I would need to.
>=20
> In one of the simulations I would like to have a beam made of
> concentric rings. Each ring has a different particle density.
>=20
> In another simulation I want to be able to have two different
> beams of different particles in the same run. And I also wonder
> if it is possible to have ellipsoidal rings instead of circular ones.
>=20
> If anyone has already made source routines to achieve what I describe
> above I would be really grateful if they would allow me to use them.
> Otherwise I bet I will send more emails to this group asking for clues
> on how to do what I intend to. I am also trying to make sense of the
> 'how to modify the source routine' lecture.
>=20
> Thanks for your time,
>=20
> Luis
Received on Mon Nov 24 2008 - 23:00:56 CET