FLUKA: Erratum!!!! (SOURCE routine of Yann Foucher)

[Alberto Fasso' <Alberto.Fasso@cern.ch>]

I owe an apology to Yann Foucher, Piero Neuhold, and possibly to other
users for a wrong information I have given in my messages of June 19
and 25.

Yann wanted to define an isotropic source distributed in space
inside an annular cylinder:
> > Rmin = 2.7 cm
> > Rmax = 3.1 cm

I said:

> For the above you don't need a special source. It is better to
> do as much as possible via the normal input file, and to 
> add (or override) in SOURCE anything else which cannot be defined 
> in a simpler way. 

This is not true. Simple numerical values input with options BEAM
and BEAMPOS are indeed available in SOURCE, where they can be left as
they are or overridden:

  PBEAM  : the particle momentum
  XINA, YINA, ZINA : the starting coordinates
  TINX, TINY, TINZ : the direction cosines of the particle

but if any of the above has been defined as extended (for instance
if the user has defined a momentum spread, or - as it was in Yann's
question - an annular beam or a beam divergence), this request 
IS CANCELED by the call to a user SOURCE. Unfortunately, in this case the
user must do the sampling himself.

Sorry for misleading you. Next time I will double-check the code before
answering a question!


    Alberto


-- 
Alberto Fassò
CERN-EP/AIP, CH-1211 Geneve 23 (Switzerland)
Phone: (41 22) 767 2398    Fax: (41 22) 767 9480   Alberto.Fasso@cern.ch