[Gate-users] [Fwd: Zero keV for Compton Hits]

[Marc Verderi]

Hello,

Frankly speaking, the non-zero energy deposited by the lowE package is 
more difficult to interpret to me. In a Compton interaction, the energy 
is not deposited directly by the gamma iself, but by the subsequent 
electron ejected off its atom. Imagine the electron is of energy high 
enough to exit your detector, then the energy transfered to the electron 
by the photon is not fully deposited in your detector. This situation 
can not be known at the time the Compton interaction occurs, and Geant4 
has to trace the ejected electron.
I would guess the deposited energy here by the lowE package is only part 
of the total energy deposited the Compton interaction + ejected electron 
(low energy electron under some threshold ?).

I will forward your message to Geant4 experts (unless someone has 
already a more complete explanation ?).

Cheers,
Marc Verderi (Geant4 member)

venialgo at cae.cnea.gov.ar a écrit :
> ---------------------------- Mensaje original ----------------------------
> Asunto: Zero keV for Compton Hits
> De:     venialgo at cae.cnea.gov.ar
> Fecha:  Mar, 11 de Marzo de 2008, 11:30 am
> Para:   gate-users at lists.healthgrid.org
> --------------------------------------------------------------------------
>
> Hello Gate-Users,
>
> I'm studying the multiple interactions in a crystal of NaI. And I have
> different results for each  physics package. When I set up Standard Energy
> Process, the Energy deposited by Compton's hits is ZERO keV for all. And
> When I set up Low Energy Process I get the expected energy spectra for
> Compton's hits.
>
> The questions is ....  Why do I have ZERO keV for Compton in Standard Energy?
> P.D. : I've attached the histogram and macro files for each case.
>
>
>   Thanks in advance.
>
>
>   Esteban Venialgo
> ------------------------------------------------------------------------
>
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