Re: [fluka-discuss]: Scoring Absorbed Dose

From: Mina Nozar <nozarm_at_triumf.ca>
Date: Thu, 27 Feb 2014 13:03:43 -0800

Hello Francesco,


I completely understand the difference B/N 'binning' and 'region'
definition in USRBIN (or at least I think I do). In the 'binning'
case, quantities scored are given as /cm3*primary but for 'region' case,
the quantities are given over the volume of the region (so
integrated/total values).

The manual, under USRBIN, note 5 says:

5. Energy deposition will be expressed in GeV per cm3 per unit primary
weight.
    Doses will be expressed in GeV/g per unit primary weight. To obtain
dose in Gy, multiply GeV/g by 1:602176462  10E7.

Why is the unit for the the Dose scored as the quantity, not GeV/g/cm3
here??? This is inconsistent with note 13:
"The results from USRBIN are normalised per unit volume and per unit
primary weight, except for region binnings and special user-de ned
binnings, which are normalised per unit primary weight only"

----------------------------------------------------------------

The forum links you have sent, say in USRBIN region binning, the units
are GeV/[g/cm3] when one scores Dose and has to multiply to results by
the volume to get the actual dose [GeV/g]. Fine, but this should be
added to the manual.

We used SCORING through score as a cross-check of the USRBIN Region
binning results.
Can we compare (non-normalized values) from SCORE for deposited energy
to Dose from USRBIN region binning, scoring Dose, by dividing the dep.
energy values in through SCORE by the mass of the region???
I guess the question is whether deposited energy and absorbed dose are
related.

Thank you in advance,
Mina

On 14-02-27 02:02 AM, Francesco Cerutti wrote:
>
> Hallo Mina & Martin,
>
> you do not need to send your inputs, your expectations concerning
> USRBIN per region are wrong, not complying with what is written in the
> manual (USRBIN, Note 13) and with what has been already explained in
> this forum
> (http://www.fluka.org/web_archive/earchive/new-fluka-discuss/4288.html,
> http://www.fluka.org/web_archive/earchive/new-fluka-discuss/3458.html).
>
> Once more: FLUKA does not know region volumes, so values per region
> cannot be normalized per region volume. If you ask for ENERGY, you
> will get GeV (per primary) and not GeV/cm3, if you ask for DOSE you
> will get the same as before divided by the material density (i.e.
> GeV/(g/cm3) and not GeV/g).
>
> (Only) SCORE values can be normalized by region volumes provided that
> one inputs them (though the practical benefit of that is quite
> questionable - I'm not aware of anybody using it -, since one can
> always renormalize SCORE values at postprocessing level; all this
> still assuming that people actually use values from SCORE, which is an
> historical scoring option not supporting automatic statistical
> analysis). If not, a default value of 1cm3 is used for normalization
> purposes as you noticed, meaning that the SCORE value for ENERGY
> should be intended as GeV, contrary to your conclusions and according
> to what is in the manual (SCORE, Note 4).
>
> Coming now to your case 2b, if you follow the manual and set IVLFLG =
> 3 in the geometry title card and write the volumes (in fixed format:
> 10 fields per region, 7 regions per row) before the GEOEND card (after
> the region END card), everything works as expected: the SCORE values
> will get normalized by your volumes and the latter ones will appear in
> the volume column. You still got default volume values of 1cm3 due to
> a Flair bug, not translating correctly what was input in the region
> metacard under the Volume label. This is going to be fixed in the next
> Flair version (by the way, Flair 2 is coming!), but it gives me the
> nasty opportunity to remind people that in case of problems and
> unexpected behaviors one should look at the input file as actually fed
> to FLUKA, leaving for a little while the wonderful Flair world and
> using a trivial text editor to inspect what is underneath.
>
> Best wishes
>
> Francesco
>
> **************************************************
> Francesco Cerutti
> CERN-EN/STI
> CH-1211 Geneva 23
> Switzerland
> tel. ++41 22 7678962
> fax ++41 22 7668854
>
> On Thu, 27 Feb 2014, Mina Nozar wrote:
>
>> Hello everyone,
>>
>> We are trying to score Absorbed Dose in a given region. We have
>> tried two scoring methods:
>> 1) via a USRBIN card with REGION binning and DOSE as the quantity scored
>> and
>> 2) via a SCORE card and Energy as the quantity scored, with no volume
>> input (case 2a) and with volume input (case 2b).
>>
>> According to the manual, we should get
>> - GeV/g per primary for option 1
>> - GeV per primary for option 2a
>> - GeV/cm3 per primary for option 2b
>>
>>
>> As for the volume setting for the SCORE card, we set IVFLG to 3 in
>> the GEOBIN title card and inputted the region volume in the geometry
>> region card for the region.
>>
>>
>> We are seeing some discrepancies. The value we get from SCORE (with
>> no volume setting, case 2a) agrees with the value from the USRBIN, if
>> we divide the SCORE value by the density. This implies that the
>> SCORE value is GeV/cm3 per primary which doesn't agree with what is
>> in the manual.
>>
>> Furthermore, when we do set the volume, following the instructions
>> above, we still see a value of 1.000000000D+00 for the region's
>> volume and the same deposited energy value as in case 2a.
>>
>> This is a source of confusion for us and we are eager to find whether
>> we are missing something. Can someone shed some light on this please?
>> Is there another way to score absorbed dose in a region?
>>
>> Thank you very much,
>> Mina & Martin
>>
>>
>
Received on Thu Feb 27 2014 - 23:08:50 CET

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