Dear Andrea,
Thank you for your response! I'm actually running the simulation again with
a smaller phantom to check if the prompt photon of the reaction appears.
Nevertheless, there is another discrepancy that makes me think something in
my input is probably not ok: according to the Do-Kun Yoon et. al.
paper *"Application
of proton boron fusion reaction to radiation therapy: A Monte Carlo
simulation study", *the high LET of the alpha particles provides a dose
enhancement, that was checked with the MCNP code. The results I obtain with
FLUKA for simulations with and without boron shows exactly the contrary for
concentrations greater than 5% w/w of Boron. Find the graphic for this
attached.
Sorry for the inconvenient, and thank you again for your response!
------------------------------------------------------------------------------------------
Lic. Federico Alejandro
Geser,
PhD. Student – Of. 232 - FAMAF (UNC),
Córdoba CONICET - Argentina,
D.N.I.:
34.682.776.
------------------------------------------------------------------------------------------
2017-04-15 7:35 GMT-03:00 Andrea Fontana <andrea.fontana_at_pv.infn.it>:
> Dear Federico,
> I ran your example and see the problem: the 8Be transition is
> included in FLUKA, but you cannot see it because you score a USRBDX
> from the PHANTOM to the VOID and your PHANTOM of water is too big
> (cylinder radius 5 cm and heigth 10 cm). So the prompt gamma radiation
> is absorbed in water. To see this you can replace water with air.
>
> As a reference, a gamma of 1 MeV in water has an half-value thickness,
> i.e. a thickness required to reduce the intensity by half, of about
> 10 cm.
>
> You can try to reduce the water thickness or score from the boron
> targets to water directly.
>
> Hope this helps,
> Andrea
>
>
> Il 14/04/2017 22:07, Federico Geser ha scritto:
>
>> Dear FLUKA experts,
>>
>> I'm interested in making proton beam simulations taking into account the
>> reaction with the 11B nucleus, leading to 3 alpha particles. This reaction
>> has the peculiarity that one of the products, the 8Be nucleus, is in an
>> excited state that emits mono-energetic prompt gamma of E=719 keV on decay.
>>
>> I've already changed the defaults to HADROTHErapy, and just in case,
>> added the PHYSICS cards to enable coalescence, evaporation, etc. I also
>> compiled linking with the *ldpm3md *event generator.
>>
>> Nevertheless, the photon spectra does not include this prompt photon
>> peak. This reaction is not included in the FLUKA libraries or did I miss
>> something in the simulation setup?
>>
>> I attach the input files.
>>
>> Regards!
>>
>> ------------------------------------------------------------
>> ------------------------------
>> Lic. Federico Alejandro Geser,
>> PhD. Student – Of. 232 - FAMAF (UNC),
>> Córdoba CONICET - Argentina,
>> D.N.I.: 34.682.776.
>> ------------------------------------------------------------
>> ------------------------------
>>
>>
> --
> ========================================================================
> Dr. Andrea Fontana tel: +39 0382 987991
> Istituto Nazionale fax: +39 0382 423241
> di Fisica Nucleare
> Sezione di Pavia e-mail: andrea.fontana_at_pv.infn.it
> Via Bassi 6 web : www.pv.infn.it/~fontana
> 27100 PAVIA, Italy
> ========================================================================
>
>
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Received on Mon Apr 17 2017 - 18:38:50 CEST