**From:** Sébastien WURTH (*wurth@ipno.in2p3.fr*)

**Date:** Tue Sep 06 2005 - 15:49:58 CEST

**Previous message:**John Clem: "Re: Problem to set DIVBM in source.f file"**Maybe in reply to:**Sébastien WURTH: "Problem to set DIVBM in source.f file"**Next in thread:**John Clem: "Re: Problem to set DIVBM in source.f file"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ] [ attachment ]

Thank you very much John, indeed it helps.

I was trying to think about such a method when I received your mail and

suddenly it went much faster, because my fortran is not so "fluent".

Like I said in my previous mails, I was unable to set properly DIVBM

value in source.f, I always had that beam directed to Z axis (the

default settings) and nothing changed.

So much for DIVBM then, your method defines exactly what I need.

Thanks again.

Regards.

Sébastien.

John Clem a écrit :

*>
*

*> Sebastien,
*

*>
*

*> The directional cosines (as well as the vertices, particle type,
*

*> energy, etc) can also be completely controlled within source.f
*

*> The modifications should take place in the code where the values
*

*> UBEAM,VBEAM,WBEAM are defined. Below is an example for generating a
*

*> 4pi isotropic angular distribution
*

*>
*

*> * Cosines (tx,ty,tz)
*

*> COSTH = ONEONE-2.D0*RAN(ISEED)
*

*> IF(COSTH.GT.ONEONE) COSTH=ONEONE
*

*> IF(COSTH.LT.-ONEONE) COSTH=-ONEONE
*

*> ANG = TWOPIP*RAN2(ISEED2)
*

*> UBEAM=SQRT(ONEONE-COSTH*COSTH)*COS(ANG)
*

*> VBEAM=SQRT(ONEONE-COSTH*COSTH)*SIN(ANG)
*

*> WBEAM=COSTH
*

*>
*

*> ONEONE and TWOPIP are define in the common DBLPRC and RAN* are
*

*> externally defined random number generators.
*

*>
*

*>
*

*> I hope this helps,
*

*> John
*

*>
*

*> >>
*

*> >>Dr. John Clem
*

*> >>Senior Research Scientist
*

*> >>Bartol Research Institute
*

*> >>University of Delaware
*

*> >>Newark, DE 19716 USA
*

*> >>302-831-4354
*

*> >>302-831-1843 Fax
*

*> >>clem@bartol.udel.edu
*

*> >>
*

*>
*

*>
*

*> ----- Original Message -----
*

*> *From:* Sébastien WURTH <mailto:wurth@ipno.in2p3.fr>
*

*> *To:* John Clem <mailto:clem@bartol.udel.edu>
*

*> *Sent:* Tuesday, September 06, 2005 03:08
*

*> *Subject:* Re: Problem to set DIVBM in source.f file
*

*>
*

*> John Clem a écrit :
*

*>
*

*>> Sebastien,
*

*>>
*

*>> To do this in a single run a random number generator function
*

*>> must be defined in source.f (I've forgotten exactly how to
*

*>> use the fluka internal function, however the Numerical Recipes
*

*>> libraries has various types that can be inserted directly into
*

*>> the code) and then weighted to provide the normalized integral of
*

*>> each Cobalt energy peak. Each time a new beam particle is started
*

*>> "source.f" is called and a new random number (between 0,1) is
*

*>> generated. Employing logical IF statements, the random value
*

*>> determines the energy. As an example...
*

*>> if(ranvalue.lt.0.499) E= 1.173E-3GeV
*

*>> if(ranvalue.ge.0.501) E=1.332E-3GeV
*

*>> where ranvalue variables are the random values from a
*

*>> flat distribution generator...
*

*>>
*

*>> Of course performing multiple runs with different energies
*

*>> and combining output will also achieve the same result..
*

*>>
*

*>> John
*

*>>
*

*>> ----- Original Message -----
*

*>> *From:* Sébastien WURTH <mailto:wurth@ipno.in2p3.fr>
*

*>> *To:* fluka-discuss@fisica.unimi.it
*

*>> <mailto:fluka-discuss@fisica.unimi.it>
*

*>> *Sent:* Monday, September 05, 2005 10:46
*

*>> *Subject:* Problem to set DIVBM in source.f file
*

*>>
*

*>> Hello all,
*

*>>
*

*>> Let me please remind you what brought me here :
*

*>>
*

*>> **** First Message ***
*

*>>
*

*>>/Date: Wed, 31 Aug 2005 15:24:22 +0200
*

*>>> From: "[ISO-8859-1] Sébastien WURTH" <wurth@ipno.in2p3.fr>
*

*>>> To: support@fluka.org
*

*>>> Subject: How can I define a non monoenergetic source in FLUKA ?
*

*>>>
*

*>>> Dear FLUKA developpers,
*

*>>>
*

*>>> I'm trying to simulate a source of cobalt 60.
*

*>>> I've read the manual very carefully, and a large part of the mailing
*

*>>> list archive
*

*>>> but I didn't find the right answer to my question.
*

*>>> How can I define a non monoenergetic source (or beam) ? By using the
*

*>>> subroutine source introduced by command SOURCE I guess,
*

*>>> but I don't know how to define two energies in source.f. I've tried to
*

*>>> define it with the two BEAM cards, but FLUKA seems to overwrite
*

*>>> the first one when reading the second one.
*

*>>>
*

*>>> The answer may be very simple, but I can't find it.
*

*>>>
*

*>>> Thank you for your help.
*

*>>>
*

*>>> Best regards.
*

*>>>
*

*>>> Sébastien WURTH./
*

*>>****
*

*>>
*

*>>**** Reply of G. BATTISTONI ****
*

*>>
*

*>>/I would do like in the following:
*

*>>suppose that you have 2 different energy lines. The first emission line
*

*>>has probability P (0<P<1) and the second 1-P
*

*>>Then you create your source.f with a logic in which
*

*>>for a fraction of cases proportional to P you assign energi n.1
*

*>>and for the complementary fraction of cases you give energy n.2
*

*>>
*

*>>example:
*

*>> if (flrndm(xdummy).Le.prob1) then
*

*>> pbeam = energy1
*

*>> else
*

*>> pbeam = energy2
*

*>> endif
*

*>>
*

*>>It is up to you to provide the right values for prob1, energy1 and
*

*>>energy2.
*

*>>For instance you can pass these values to the source.f using the
*

*>>numerical fields of SOURCE card: they appear inside source as the vector
*

*>>WHASOU(n) with n =0,1,2,..,6
*

*>>
*

*>> Giuseppe Battistoni/
*

*>>
*

*>>*****
*

*>>
*

*>>
*

*>>
*

*>>
*

*>> _/So, there is my new problem :/_
*

*>>
*

*>>
*

*>> I did the changes by calling source.f with SOURCE card,
*

*>> setting my parameters in the WHASOU fields of SOURCE...
*

*>> compiling, linking, etc.
*

*>> The run goes to the end, but the results are not quite what I
*

*>> was expecting.
*

*>>
*

*>> It seems that FLUKA understands that my source (beam) is not
*

*>> isotropic anymore, but directed to z axis,
*

*>> although I gave a value to variable DIVBM in my source.f file.
*

*>>
*

*>> I set DIVBM to 1.E4 to describe an isotropic source, value
*

*>> taken from the examples in BEAM card
*

*>> description section from the manual. By the way, I discovered
*

*>> a little mistype in the example of an isotropic Cs-137 source,
*

*>> kinetic energy should be -661.7E-6 GeV instead of -661.7E-3
*

*>> GeV, shouldn't it ?
*

*>>
*

*>> Anyway, my question is : Is there any particular place in
*

*>> source.f where those assignments have to be made ?
*

*>> In the user initialization part for example ? I tried this
*

*>> one though, but nothing changed.
*

*>> I tried after the energy part (an analogy to BEAM card in my
*

*>> logic), but nothing changed, once again.
*

*>> It appears to me that DIVBM is not read properly (and maybe
*

*>> the energy part too (not sure about that)).
*

*>>
*

*>> I did a run without changing anything in the source.f file
*

*>> given in $FLUPRO/usermvax, the results are quite the same when I
*

*>> gave a value to DIVBM.
*

*>>
*

*>> Thank you for your help.
*

*>>
*

*>> Best regards.
*

*>>
*

*>> Sébastien Wurth.
*

*>>
*

*> John,
*

*>
*

*> Thank you for your answer, but it's not exactly what I was asking
*

*> for. Your solution is quite the same that G. Battistoni gave me a
*

*> few days ago and that a good way to simulate a cobalt source, no
*

*> doubt. But actually my new problem is how to define an isotropic
*

*> source in source.f routine. When using SOURCE card in Fluka this
*

*> overrides the beam divergence given in BEAM card. My question was
*

*> where do I exactly define this DIVBM value in source.f file since
*

*> it doesn't seem to be properly read at the location I put it so far...
*

*>
*

*> Regards.
*

*>
*

*> Sebastien.
*

*>
*

**Previous message:**John Clem: "Re: Problem to set DIVBM in source.f file"**Maybe in reply to:**Sébastien WURTH: "Problem to set DIVBM in source.f file"**Next in thread:**John Clem: "Re: Problem to set DIVBM in source.f file"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ] [ attachment ]

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