Re: question about AUXSCORE card + dose

From: Ercan Pilicer <ercanpilicer_at_gmail.com>
Date: Sat, 11 Jul 2009 21:15:36 +0200

an answer just for 3rd questions appears below.

On Sat, 2009-07-11 at 15:09 +0530, Mr. Bhushankumar Jagnnath Patil.
wrote:

> Dear sir,
> Very much thankful to the nice explanation on dose deposition by
> particles. I want to discuss few points regarding this
>
> 1. Dr Andrea suggest me to use two AUXSCORE with SDUM =AMB74 for
> dose-equivalent and without SDUM for dose calculation . But the default
> setting is AMB74 for SDUM in auxscore card. That gives the same results as
> it was before.
>
> 2. As I am passing 15MeV electron on Tungsten. I have made Pcut in 15MeV
> in water phantom. And this gives me the maximum dose deposited by photon.
> But as all the photons are get deposited in few milimeters of water. So
> there is no photons in forward direction.
>
> 3. Actually I want to caluate the depth dose curve in water. How can I
> calculate?

concerning about depth dose distribution,and assuming you scored
deposited energy by USRBIN card. you get GeV/cm3/pr and than multiply
your results with surface area of your target and GeV to MeV. so you get
MeV/cm/pr. than you can plot it within Flair, powerful interface. usrbin
1d plot along Z-axes. (thanks Vasilis)

>
> 4. We have measure the dose of the system by ionization chamber and it is
> giving 6000Rad/min at 1 meter. I want to check this with fluka. I have
> converted the fluence spectra to dose and it is giving me near about same
> answer. I am trying, Is it possible to get the same using dose (228)
> option of the fluka ? so that I dont have to convert it.
>
> Shall I consider the all particle dose to find out the depth dose curve in
> water phantom and the dose calculation ?
>
> Sir I have one more question can you write something on How the
> dose-equivalent is calculated in fluka? or if it is written somewhere
> point it out to me.
>
> Thanking you.
>
>
>
> > Probably you will judge me pedantic, but I would like to add a
> > clarification.
> > What Andrea said is exact, concerning the way the dose is technically
> scored
> > by FLUKA. But be careful: what happens in the real physical world is
> different.
> > In the real world photons don't ever deposit ANY dose: they are
> indirectly
> > ionizing and the ionization is all done by electrons and positrons
> liberated or produced by photons.
> > In FLUKA, energy is "deposited by photons" when the photon energy
> becomes
> > lower than the photon transport threshold: that energy is then deposited on
> > the spot. See value of Pcut on your *.out file (search for the string
> > "Correspondence of regions and EMF-FLUKA material numbers and
> names").
> > You can change that threshold using command EMFCUT
> > Probably there are also a few other rare cases, for example when
> fluorescence/Auger has not been requested and the corresponding energy
> is deposited on the spot.
> > In any case, it must be clear that the amount of "photon dose" is
> strictly
> > related to user choices: if you change the cutoff energy, you get a
> different result. And the "photon dose", being only the energy of
> photons
> > below threshold, is obviously always smaller than the "electron dose".
> >
> > And, despite the popular success among the users of the possibility to
> filter dose deposition with AUXSCORE, getting "neutron dose", "proton
> dose", etc., it must be remembered that nearly ALL dose is electron
> dose. "Proton dose" is energy transferred by protons to electrons with
> energies lower than the delta-ray threshold (again, dependent on a user
> choice). "Neutron dose" in FLUKA is kerma, which in the real world would
> be ionizing charged recoils, and they too would ionize by transferring
> energy to electrons.
> > The only exception of NIEL=Non Ionizing Energy Loss, which will
> > be introduced soon into FLUKA, and which refers to kinetic energy
> transferred to nuclei without ionization. But I am not sure that it must
> be considered part of the dose, and anyway it is always many orders of
> magnitude smaller than dose from ionization.
> >
> > So, to summarize: if FLUKA allows you to calculate dose not due to
> electrons, it is only a technical artifact, with results depending on
> your threshold settings (transport thresholds or delta-ray production
> thresholds). In the real world there is only electron dose.
> >
> > Alberto
> >
> > On Thu, 9 Jul 2009, Andrea.Mairani_at_mi.infn.it wrote:
> >
> >> Dear user,
> >> about
> >> "If I want to measure the DOSE deposited by only photon and only
> electron how can I measure it with USRBIN card ?"
> >> See the information written in the manual for the AUXSCORE card: Examples:
> >> *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
> USRBIN 10.0 208.0 -50.0 10.0 10.0
> 10.0Ene.p
> >> USRBIN -10.0 -10.0 -10.0 100.0 100.0 100.0&
> AUXSCORE 2.0 1.0 1.0
> >> * The above AUXSCORE card will filter the energy scoring of the *
> USRBIN card to only the energy that is deposited by protons In
> your input you've used:
> >> USRBIN 10.0 228.0 -86.0 35.0 35.0
> >> 133.0ElectronB
> >> USRBIN -35.0 -35.0 98.0 70.0 70.0 70.0
>
> >> &
> >> USRBIN 10.0 240.0 -87.0 35.0 35.0
> >> 133.0ElectronB
> >> USRBIN -35.0 -35.0 98.0 70.0 70.0 70.0
>
> >> &
> >> AUXSCORE 2.00 3.0 6.0 7.0 AMB74
> >> I think that you've to change the:
> >> AUXSCORE 2.00 3.0 6.0 7.0 AMB74
> >> in:
> >> AUXSCORE 2.00 3.0 6.0 AUXSCORE
> >> 2.00 3.0 7.0 AMB74
> >> In this way, you've the dose due to electrons in ***fort.86 and the
> equivalent dose due to elctrons in ***fort.87.
> >> Ciao
> >> Andrea
> >
> > --
> > Alberto Fasso`
> > SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025
> > Phone: (1 650) 926 4762 Fax: (1 650) 926 3569
> > fasso_at_slac.stanford.edu
> >
>
>
> Mr. Bhushankumar Jagnnath Patil.
> Microtron Accelerator Lab.
> Department of Physics,
> University of Pune,
> Ganeshkhind, Pune 411007
> Ph. No. Off. 020-25692678 Ext. 421
> Mob. 9823968377
> Webpage http://physics.unipune.ernet.in/~bjp
> Alternate e-mail amolbhushan_at_gmail.com
>
>
>
Received on Sun Jul 12 2009 - 12:27:32 CEST

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