Re: [fluka-discuss]: Scoring energy spectrum Cs-137 in LaBr3

From: Paola Sala <paola.sala_at_mi.infn.it>
Date: Fri, 24 Jun 2022 10:55:04 +0200

Hello
apologies for the very late reply.

The peak at about 65 keV is the artificial superposition of two x-ray
lines. This happens because radioactive decays are simulated in an
"inclusive" way, that respects the average spectra and multiplicity, but
does not correlate the decay products at single event level. Work on
makin  radioactive decay fully analogue is in the todo list, albeit not
on a short timescale.

Paola


On 3/1/22 12:55, Francesca Ferrulli wrote:
> Dear FLUKA experts,
>
> I simulated a LaBr3 crystal and I want to score the energy spectrum of
> a Cs-137 source and compare it with the result I got experimentally. I
> simulated the source using the ISOTOPE option and HI-PROPE card as a
> cylindrical source in a plastic encapsulation (as in the linked post).
> The LaBr3 is covered by an aluminum layer and it has a window since it
> is hygroscopic. I do not know the exact design of the scintillator,
> but I also assumed it’s SiO2 the window and 3 mm thick.
>
>
> I scored the number of events inside the LaBr with the card DETECT and
> applied a GEB assuming FWHM = a +b*(E+cE^2)^(1/2) where a,b,c were
> obtained from the experimental spectra.
>
>
> I set both the transport and production energy threshold of electrons
> and photons to 10 keV which is the threshold of my detector.
>
>
> I attach the simulation results (after the GEB) and experimental
> results. The photoelectric peak and the Compton edge are well
> reproduced, differences in the backscattered peak are expected since
> the actual crystal is enclosed in case which I did not simulate.
> However I do not understand the peak at about 65 keV. I see from the
> previous post that the same peak was detected (is it at the same
> energy or am I wrong?).
>
> I also attach my input file.
>
>
> Best regards,
>
> Francesca
>
>


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Received on Fri Jun 24 2022 - 12:32:17 CEST

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