RE: Energy deposition scoring for electrons or photons

Dear Georgios
The problem is in the MAT-PROP card: the way it is defined now,
the usrmed routine is called for materials 12 to 29 in step of
three...but 29-12=17, NOT a multiple of three.
You can issue two separate cards for the two materials, it will work.
Then, the coding with newreg and mreg is correct: you'll kill photons
going from copper to gas.
Have a nice day
Paola

On Mon, 2011-03-07 at 16:19 +0100, Georgios Tsiledakis wrote:
> Dear Paola,
>
> I tried to follow your suggestions using the usrmed.f routine.
> I have added in my input
> MAT-PROP 1.0 0.0 0.0 12.0 29.0 3. USERDIRE
> where 12.0 is the copper that surrounds the gas mixture 29.0
> The region of the copper is 2.0 and of the gas 3.0
> I would like to measure the energy deposited in the gas that comes only from photons or only from electrons
> when the source for example is 1.3 MeV point source inside the Copper shell.
>
> -By adding in the usrmed.f the lines:
> ------------------------------------------------------
> IF ( MREG .EQ. 3 ) THEN
> IF ( IJ .EQ. 3) WEE = ZERZER
> END IF
> -----------------------------------------------------
> I realise that I kill all the electrons in the region 3 (copper) that might give photons and finally conversions into the gas. As a result, I am getting very few which is wrong...
>
> -If I write it as follows it is also wrong....
>
> IF ( IJ .EQ. 7 ) THEN
> IF ( MREG .EQ. 3 .AND. NEWREG .EQ. 4 ) WEE = ZERZER
> END IF
>
> Could you please let me know how to kill this particles not in the region but in the boundary?
> I had a look at the manual without success. Is it a good idea to define a new tiny spherical shell that separates
> gas from copper and kill by WEE = ZERZER selectively what I would like?
>
>
> Thank you very much for your help
>
> Best regards
>
> Georgios
> ________________________________________
> From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of paola sala [paola.sala_at_cern.ch]
> Sent: 28 February 2011 17:35
> To: Georgios Tsiledakis
> Cc: fluka-discuss_at_fluka.org
> Subject: Re: Energy deposition scoring for electrons or photons
>
> Dear Georgios,
> to separate electron and photon contributions yohave to set up
> some user code. No automatic distinction is possible at scoring time,
> since all energy deposition will be done by electrons, even when the
> primary is a photon.
> You can proceed in several ways. For example:
> - through the usrmed.f routine, selectively kill electrons or photons at
> the boundary between copper and gas
> - trhough the stack user variables, set one or several flags recording
> the history of the particle . This can be done with the stupre.f routine
> at interactions, and/or with the bxdraw entry of mgdraw.f at boundaries.
> A user-written comscw.f can then select wether to score or not
>
> For hints on user routines, you can have a look in the manual, and also
> in the lectures of the advances fluka course ( on the program page)
>
> As for neutrons: the threshold at 20 MeV is not a threshold..is a
> boundary between two different transport methods. Above this, neutrons
> are treated like all other hadrons. Below 20 MeV, their transport and
> interactions are simulated on the basis of cross section libraries, with
> the so called muti-group transport. In both cases you will get the enrgy
> deposition from recoils, however below 20 MeV the recoils and reaction
> products other than neutrons and photons will not be transported, theyr
> energy will be deposited at the interaction point. ( except for
> interactions on Hidrogen) Again, for a description of the low energy
> nmeutron transport in fluka, please refer to the dedicated section in
> the user manual
>
> Hope this helps
> Paola
>
> On Fri, 2011-02-25 at 09:41 +0000, Georgios Tsiledakis wrote:
> > Dear fluka experts,
> >
> > I had a copper sphere that surrounds a gaseous volume of Ar-CH4 at 50
> > mb.
> > With a modified source.f routine (thanks to your very fruitful
> > explanations at the list)
> > I generate photons of 1.3 MeV randomly in the copper shell and score
> > at the gas using
> > the EVENTBIN card and a manipulation in fortran/root.
> > The energy deposition (EM) is given at the attached picture where you
> > could see the Copper
> > peak around 8 keV (200 entries above a background in 2 peaks)
> >
> > My questions are the following:
> >
> > 1)Is the background of around 60 counts at 8 keV purely electrons?
> >
> > 2)how I could repeat the study BUT measure the Edep only from photons
> > or only from electrons?
> > Since fluka gives 208 and 211 options. Is any easy way to discard
> > for example conversions of Copper
> > and so, all I could see at the plot to be purely electrons or the
> > opposite?
> >
> > 3)There is a threshold of 20 MeV for neutrons. Can I use a neutron
> > source of 2 MeV and see the recoils?
> > How FLUKA treats neutron-nucleus collisions? Is it efficient for
> > (Α, n) reactions? 1-2 MeV neutron
> > can be used?
> >
> > Thank you very much in advance
> >
> > Best regards
> >
> > Georgios
> >
> >
> >
> >
>
>
Received on Tue Mar 08 2011 - 09:48:24 CET