Dear Anna,
Thank you for the explanation. I now understand that the protons are
ranged out; however, I don't understand the shape of the spectrum. I
would have expected a gradual drop off of the protons with decrease in
energy but what I see is a drop at 10 MeV, then a rise, a bit of a
plateau, then a sharp drop off at 1 MeV.
What is responsible for the observed distribution?
Thank you and best wishes,
Mina
On 15-02-21 10:28 AM, Anna Ferrari wrote:
> Dear Mina,
>
> in FLUKA setting a threshold for heavy charged particles does not
> mean that you stop the transport, but that you stop the very refined
> transport: below the threshold the transport is more crude, but
> whatever the threshold is heavy charged particles are ranged out to rest.
> An exception is if the energy cutoff has been set by the user > 100 MeV.
> As you know, the situation is different for electrons/positrons:
> ranging out is not done, mainly because it is difficult to define with
> precision a residual range (you can see
> http://www.fluka.org/web_archive/earchive/prova/1305.html )
>
> Greetings!
> Anna
>
> Am Thu, 19 Feb 2015 12:56:05 -0800 schrieb Mina Nozar <nozarm_at_triumf.ca>:
>> Hello everyone,
>>
>> I just did a quick study, looking at the energy/power deposition in
>> an Al flange, enclosing an Indium seal. The flange sits upstream of
>> a Be target (at a 45 deg angle and a distance of 45 cm from the
>> target). The target is bombarded by 480 MeV proton beam.
>>
>> I chose NEW_DEFA as the defaults (so a PART-THR of 10 MeV for
>> protons). I did not lower this threshold using PART-THR card. When I
>> look at the particle fluences in the Al flange (beam particles,
>> protons, and neutrons), I see protons down to 1 MeV energies and I am
>> wondering why. It is like seeing a second set of data from 10 to 100
>> MeV.
>>
>> Please see the image enclosed.
>>
>> Thank you very much for helping me understand what is going on.
>>
>> Best wishes,
>> Mina
>>
>>
>>
>>
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Dr. Anna Ferrari
> Institute of Radiation Physics
> Helmholtz-Zentrum Dresden-Rossendorf e.V.
> Tel. +49 351 260 2872
> a.ferrari_at_hzdr.de
> http://www.hzdr.de
>
> Vorstand: Prof. Dr. Dr. h. c. Roland Sauerbrey, Prof. Dr. Dr. h. c. Peter
> Joehnk
> Vereinsregister: VR 1693 beim Amtsgericht Dresden
>
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Received on Tue Feb 24 2015 - 22:32:37 CET