Re: [fluka-discuss]: Total efficiency of plastic scientillator

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Wed, 12 Oct 2016 12:31:02 +0200

Hi Zafar,

you miss the fact that for neutrons below 20 MeV, in the context of the
adopted multigroup treatment, you cannot see in the simulation any
secondary product (but neutrons and photons) except for few materials
where the pointwise treatment can be switched on (this is not the case for
carbon in FLUKA2011). Their contribution to energy deposition is
anyway taken into account in the kerma approximation (for a fixed neutron
energy in a given material this corresponds to a fixed value you will
get scored).

As a side note, while USRTRACK gives particle fluence differential in
particle kinetic energy, USRBIN gives indeed deposited energy, contrary
to what you say.

Kind regards

Francesco

**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. ++41 22 7678962
fax ++41 22 7668854

On Wed, 12 Oct 2016, Zafar Yasin wrote:

>
> Dear FLUKA experts and users,
>
>
> We want to calculate the total efficiency of a plastic scintillator (BC-400), we
> have incident isotropic flat beam of neutrons from 1 to 20 MeV (at present we are
> first using a single energy).  
>
> We want total efficiency calculated using FLUKA to compare with calculated from
> Geant4, plot of efficiency using Geant4 is given below (x-axis is energy of
> neutrons in MeV).
>
>
> [IMAGE]
>
>
>  
>
> The total efficiency using Geant4 is calculated as: To calculate the efficiency at
> given energy E. It is defined as Eff (E)=Ndet/Nemitted
>
> Where Nemitted is the number of emitted particle of a given energy E.
>
> So the efficiency value at single energy 10 MeV  is:
>
>                         Eff(10 MeV)=1124/5e6 = 2.248e-4
>
> Where 1124 are detected particles and 5e6 are emitted particles.
>
>
> My first question is Why we can’t use FLUKA to calculate detector efficiency like
> methodology being used in Geant4.
>
> I was thinking DETECT card is equivalent to pulse height in a detector and can be
> used for calculate the efficiency, why it is not applicable for plastic scintillate
> as I am not getting the efficiency plot like in Geant4.
>
> Which scoring cards I should use to calculate total efficiency? USRBIN and USRTRACK
> give energy fluence not energy deposited. If I use EVENTBIN, it is difficult for me
> to process its output as I never used this card before and if EVENTBIN is like
> DETECT, then I will prefer to use DETECT card.
>
> One way to calculate intrinsic efficiency is I should use USRTRACK to calculate
> neutron and proton fluence and then the ratio =proton fluence/neutron fluence give
> the intrinsic efficiency and I am not sure is it true or not. If it is intrinsic
> efficiency how can I calculate total efficiency.
>
>  
>
> In summary, I need a efficiency curve like geant4 and how can I do that?.My input
> file is attached.
>
>
> Thank you in advance.
>
>  
>
> Best regards,
>
> Zafar Yasin
>
>
>

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Received on Wed Oct 12 2016 - 14:09:00 CEST

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