Hello everybody,
I would like to thank Dr. Mikhail Polkovnikov and Dr. Francesc Pujol for
their help!!
Kind regards,
Em sex, 22 de mar de 2019 às 10:15, Francesc Salvat-Pujol <
francesc.salvat.pujol_at_cern.ch> escreveu:
> Dear Jonas,
>
> Seems like you essentially want to simulate an x-ray tube. A few
> observations:
>
> 1) The useful photons are not those that travel further into tungsten
> (which anyway do not make it very far as you observe), but those that
> are emitted back into void. It is also customary to make the surface
> onto which electrons impact form a certain angle away from normal
> incidence, ~45 deg.
>
> If you adapt your scorings so as to see a bit of the vacuum before your
> W target, you'll see x-ray emission. To see what happens inside W, adapt
> the edges and number of bins in your USRBIN, keeping in mind that after
> say .05 cm electrons are basically out of the game.
>
> 2) As you mention, you should eventually obtain a "broad"
> Bremmsstrahlung bump and, overlaid, a few characteristic lines. In
> FLUKA, these lines will arise from the primary electron emitting a
> Bremsstrahlung photon, this photon having the possibility of ejecting an
> electron from a target atom (photoionization) and the vacancy being
> relaxed by the emission of (fluorescence) photons with characteristic
> energies. However, there is another process contributing to the
> intensity of the lines at these characteristic energies: the relaxation
> of a vacancy produced by inner-shell ionization by direct electron
> impact. The ionization process is modelled in FLUKA, but the subsequent
> vacancy relaxation not yet. Thus, your simulated characteristic x-ray
> lines would be lacking intensity.
>
> For this particular application, and considering that fluorescence from
> vacancy relaxation after inner-shell ionization will most likely
> dominate the intensity of the characteristic lines, it would make sense
> to use e.g. PENELOPE code, which does include vacancy relaxation after
> inner-shell ionization by electron impact.
>
> With kind regards,
>
> Cesc
>
>
> On Thu, Mar 21 2019, at 11:07 -0300, JONAS OLIVEIRA DA SILVA wrote:
> >
> >Dear experts,
> >
> >I'd like to obtain a filtered X-ray tungsten spectra with FLUKA, but I've
> >found some problems with the results.
> >
> >My basic idea is to use a 120 keV electron beam that interacts with a
> >cylindrical tungsten target to generate bremsstrahlung and characteristic
> >photons. This spectrum will be filtered with a 1.2 mmAl aluminum filter,
> >cylindrical shape, that is located at the end of the target. I do not know
> >what is going on because it seems that the simulated X-ray photons do not
> >reach the aluminum filter.
> >
> >The .inp file is attached.
> >
> >Kind regards,
> >
> >--
> >Prof. Dr. Jonas Oliveira da Silva
> >Instituto de Física - UFG
> >Telefone: (62) 3521 2320
>
>
>
> --
> Francesc Salvat Pujol
> CERN-EN/STI
> CH-1211 Geneva 23
> Switzerland
> Tel: +41 22 76 64011
> Fax: +41 22 76 69474
>
--
Prof. Dr. Jonas Oliveira da Silva
Instituto de Física - UFG
Telefone: (62) 3521 2320
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Received on Tue Apr 09 2019 - 15:41:15 CEST