Re: question about AUXSCORE card + dose

From: Alberto Fasso' <fasso_at_SLAC.Stanford.EDU>
Date: Sat, 11 Jul 2009 10:03:51 -0700 (PDT)

Dear Mr. Patil,

you have listed 4 issues, but they do not look all as if they were questions.
Anyway I will try to comment them.

> 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.
How do you know that "the default setting is AMB74 for SDUM in auxscore card"?
The manual does not say it, and indeed there is no default SDUM in the
program. If you want AMB74, you MUST set SDUM equal to it.

> 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.
Is this a question? Of course, if you set the transport cutoff for photons
equal to the maximum energy of the primaries, photons will never be transported
and their energy will be deposited at point of production, as I have written
in my previous e-mail. And of course there is no photons in forward direction.
It is just an artifact. What is the problem you see?

> 3. Actually I want to caluate the depth dose curve in water. How can I
> calculate?
Set the transport and the production cutoffs of both electrons and photons
low enough so that the particles with energies lower than the cutoff
would have a residual range (for electrons) or an attenuation length (for
photons) small with respect to the space resolution with which you
want to get the dose curve. Remember that positrons annihilate at the
point where they are stopped, emitting two 511 keV photons: so, in any
case set the photon cutoff lower than 511 keV, otherwise their energy
is deposited where the positron stop, which is not correct.

> 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.
Yes, that is the normal way to do 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.
The dose equivalent is calculated by folding fluence with published
conversion coefficients. See
S. Roesler and G.R. Stevenson
  deq99.f - A FLUKA user-routine converting fluence into
  effective dose and ambient dose equivalent
  Technical Note CERN-SC-2006-070-RP-TN, EDMS No. 809389 (2006)
Originally, this was a user routine to be invoked by command USERWEIG,
but now it has been included into the standard FLUKA package with a few
adjustments, and is called via AUXSCORE. I attach it to this mail for your

Kind regards,


>> 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, 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
> 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
> Alternate e-mail

Alberto Fasso`
SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025
Phone: (1 650) 926 4762   Fax: (1 650) 926 3569

Received on Sun Jul 12 2009 - 12:30:23 CEST

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