From: Markus Brugger (Markus.Brugger@cern.ch)
Date: Fri Feb 02 2007 - 12:38:57 CET
Hi,
a couple of additional comments:
source routine:
---------------
- you set "wbeam = cos(z_ang)", i.e., you particles will be started in
the positive z direction!
- the "do loop" for the angles is not really needed (however not
disturbing either)
-> changing this then results in what is shown in 'nflu.ps', perhaps
closer to what you expected to have?
-> furthermore, your positions and angles are correlated, thus the
reason why you actually 'sample' your object is that you have a
different height (z_max=150cm) and width (x/y_max=100cm) -> guessing
that's what you wanted to do
...on a different line we're not sure what exactly you would like to
achieve by sampling the 'hemisphere' and to our mind one could
distinguish two general cases:
(1) since you sample out of a uniform cos(theta)^2, i.e., theta peaks at
45deg you will get a uniform projection in x and y but not a uniform
distribution on your hemisphere (see "2dplot.ps" and "3dplot.ps"), thus
the way you sample in your input file seems somewhat a bit "complicated"
-> this connection wasn't at all obvious to us in the first place ;-)
-> perhaps in a simpler way one could also start from a homogeneous flat
(x/y) distribution and either irradiate your object in a flat way (i.e.,
by simply using the available SOURCE command) or if you want to do
sample also the direction then you could put everything accordingly into
your own source routine.
(2) if you want to uniformly sample your hemisphere you should start
from an uniform distribution in cos(theta) (e.g.,
z_ang=acos((oneone-twotwo*flrndm(xi))) -> this gives you a sphere, thus
only take the half-space of it) and then sample in addition the
direction inside this sphere (again take care about wbeam)
hope this helps
Markus
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> -----Original Message-----
> From: owner-fluka-discuss@fisica.unimi.it
> [mailto:owner-fluka-discuss@fisica.unimi.it] On Behalf Of
> g4736524@student.mahidol.ac.th
> Sent: 02 February 2007 06:18
> To: Florian Sommerer; Florian Sommerer; Markus Brugger
> Cc: fluka-discuss@fluka.org
> Subject: Re:
>
> Dear Florian,
>
> I used below command to compile the source routine,
> I just want to create the starting point of the neutron being
> the hemisphere shape above the neutron monitor because, to me
> it like the neutrons are coming to the detector from
> everywhere and uniformly distribution in cos^2 theta.
>
> flutil/lfluka -L$FLUPRO -L$FLUPRO/interface
> -L$FLUPRO/latestRQMD -l dpmjet -l r\ qmd -O dpmmvax -O
> rqmdmvax -m fluka -o cospwtwo usermvax/sourcemod.o
>
> Best regards,
> Preeksingh...
>
> Quoting Florian <florian.sommerer@cern.ch>:
>
> > Dear Preeksingh!
> >
> > I have compieled your files and could
> > create an executable but it
> > doesn't run. Could you please send how you have compiled the
> > executable.
> >
> > Beside that I see that there is a problem with your regions. The
> > following line is too long:
> > 043 +43 -42 -41 -40
> > -39 -38 -37 -36
> > -35 -34 -33 -32 -31
> >
> >
> > If you look in the *.out file you will find that FLUKA cuts
> it after
> > -35 because you exceed the 72th character of this line:
> > 043 0 43 -42 -41 -40
> > -39 -38 -37 -36
> > -35 Z 43
> >
> > Therefore the bodies 34, 33, 32 and 31 are not subtracted.
> Could this
> > be the reason for the unexpected results?
> >
> > Best regards,
> > Florian Sommerer
> >
> >
> >
> >
> > g4736524@student.mahidol.ac.th wrote:
> > > Dear Fluka author,
> > >
> > > I have modified source.f to
> > illuminate
> > > isotropic beam of neutron to my 6-tubes
> > neutron
> > > monitor but after run fluka and put the
> > binary
> > > file from USRBIN to flukaGUI, it seem
> > that the
> > > neutron beam did not reach to my monitor
> > as much
> > > as I think. Is it because of my starting
> > point of
> > > the beam far from the monitor? (i 've
> > changed from
> > > 1000 to 500 and last one is 100 as you
> > see in my
> > > attachment.) Or I did somethings wrong
> > with the
> > > source.f
> > >
> > > Ps I attached the data for using in
> > source.f and
> > > the picture from flukaGUI too.
> > >
> > > Thank in advance
> > > Best regards,
> > > Preeksingh ...
> > >
> > >
> > -------------------------------------------------
> > > This mail sent through MU-Webmail:
> > webmail.mahidol.ac.th
> >
> >
> > --
> > ###########################################
> > Florian Sommerer
> > European Organization for Nuclear
> > Research
> > CERN DSU/TT
> > Mailbox Z08700
> > Geneve 23
> > CH-1211 Switzerland
> > Tel : +41 2276 75582
> > ###########################################
> >
>
>
> -------------------------------------------------
> This mail sent through MU-Webmail: webmail.mahidol.ac.th
>
>
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