Re: Deposit dose

I missed one remark

> actually just running your Si beam input one gets 0.2 cGy as measured.

limiting the dose scoring to HEAVYION as you did (why?) by AUXSCORE, one
indeed gets 10% less

Francesco

On Sat, 29 Jan 2011, Francesco Cerutti wrote:

>
> Hi,
>
> actually just running your Si beam input one gets 0.2 cGy as measured.
>
> DOSE values scored by USRBIN *per region* represent in fact the ratio between
> the energy deposited over the whole region and the material density (i.e.
> GeV*cm3/g) and need to be divided by the region volume in order to get dose.
> Despite the fact that you input the region volumes, which are used only for
> renormalizing the quantities scored by the SCORE card, as pointed out in the
> manual (SCORE card). So applying the GeV/g->Gy conversion and multiplying by
> the integrated beam intensity (24480*20*20 ions) you end up finding the
> expected number.
>
> By the way, energy deposition density (GeV/cm3) and dose (GeV/g) are
> intensive quantities and, as such, in an uniform radiation field do not
> depend on the volume/mass extent.
>
> All the best
>
> Francesco
>
> **************************************************
> Francesco Cerutti
> CERN-EN/STI
> CH-1211 Geneva 23
> Switzerland
> tel. ++41 22 7678962
> fax ++41 22 7668854
>
> On Wed, 26 Jan 2011, Jean-Emmanuel Groetz wrote:
>
>> Dear Fluka users,
>>
>> Further to my previous message last week, I have still problems to
>> assess the dose deposited by heavy ions in a cell culture.
>> Anna and Francesco (thanks to them) show me the right way to define a
>> rectangular beam (especially the delta x and y parameters).
>>
>> To get the deposit dose in the cell culture (inside a µ-dish), I use
>> USRBIN with the dose option. I have noticed that if I change the volume
>> of the region corresponding to the cell culture, it has no effect on the
>> dose result.
>>
>> I would like to know if I misunderstand something :
>> - dose result is given in GeV/g/primary
>> - energy deposition is given in GeV/cm3/primary
>> - since the dose is in J/kg, the mass (or the volume) of the region
>> should have an importance.
>>
>>
>> In the attached example (Si ions at 600 MeV/A, 24480 ions/cm2, 20x20cm2
>> for the beam size), the dose is about 0.8 cGy (the experimental dose is
>> ~0.2 cGy and my MCNPX calculations give 0.27 cGy). For Fe ions (1 GeV/A,
>> 8323 ions/cm2, same beam size), the dose from Fluka is the same, i.e.
>> 0.8 cGy (good news!!), but it's still not the expected result, i.e 0.2
>> cGy.
>>
>> What I am doing wrong or what I have forgotten ?
>>
>> Thanks in advance.
>> Jean-Emmanuel
>>
>>
>> --
>> _____________________________________________
>>
>> Jean-Emmanuel Groetz
>> Laboratory of Physical Chemistry and Radiation
>> University of Franche-Comte
>> 16, route de Gray
>> 25030 Besancon Cedex
>> France
>>
>> mailto: jegroetz_at_univ-fcomte.fr
>> phone: +33 3 81 66 65 07
>> fax : +33 3 81 66 65 22
>> ______________________________________________
>
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Received on Sat Jan 29 2011 - 15:01:59 CET