Re: [fluka-discuss]: Implementation of Beam spectrum by SOURCE

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Wed, 4 Oct 2017 23:15:53 +0200

Dear Agnieszka,

I suspect that you look at the USRTRACK differential value (cm-2 GeV-1)
rather than at the integral fluence value (cm-2) - available in the
sum.lis file -. With one bin only and Emax beyond the electron energy
physical limit, evidently the first goes down as 1/Emax for increasing
Emax, while the latter is unchanged.
I'd also consider to score energy deposition in the ionization chamber
gas region.

Cheers

Francesco

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

On Wed, 4 Oct 2017, Agnieszka Witkowska wrote:

> Dear Francesco,
> Thank You, I think that I implemented everything needed, however my results of the
> simulations are  strange, as depending on the Emax which I put in the USRTRACK
> scoring card they are changing a lot - with increasing Emax in USRTRACK, results
> of the fluence are decreasing. Moreover, results with radioactive isotope are
> differing a lot comparing to my previous simulations witn monoenergetic beams
> (main lines of the isotopes). 
>
> Can You please have a quick look at my input file (attached) and advise what might
> be wrong in it? 
>
> I am trying to score electrons in ionization chamber by card USRTRACK with isotope
> of Co60.
>
> Best regards,
> Agnieszka 
>
> 2017-10-03 22:25 GMT+02:00 Francesco Cerutti <Francesco.Cerutti_at_cern.ch>:
>
> Dear Agnieszka,
>
> when I am using option BEAM/SDUM=ISOTOPE, what will be my
> BEAM/WHAT(1) energy? Will it be the energy of the main
> energy line for the isotope?
>
>
> no, it's meaningless, see the manual (BEAM card, SDUM).
>
> Is it also mandatory to use card DCYSCORE while using
> RADDECAY/WHAT(1)=Semi-Analogue?
>
>
> yes, but read carefully the manual (BEAM card, note 8)
>
> Best
>
> Francesco
>
> **************************************************
> Francesco Cerutti
> CERN-EN/STI
> CH-1211 Geneva 23
> Switzerland
> tel. +41 22 7678962
> fax  +41 22 7668854
>
> On Tue, 3 Oct 2017, Agnieszka Witkowska wrote:
>
> Dear Francesco,
> Thank You a lot for advise, radioactive source is exactly
> the option I was looking
> for! I have one additional question as I am a little bit
> confused, when I am using
> option BEAM/SDUM=ISOTOPE, what will be my BEAM/WHAT(1)
> energy? Will it be the
> energy of the main energy line for the isotope?
>
> Is it also mandatory to use card DCYSCORE while using
> RADDECAY/WHAT(1)=Semi-Analogue?
>
> Thank You for your help in advance.
>
> Best regards,
> Agnieszka Witkowska
>
> 2017-10-02 12:05 GMT+02:00 Francesco Cerutti
> <Francesco.Cerutti_at_cern.ch>:
>
>       Dear Agnieszka,
>
>       are you interested in decay alphas? Or photons and
> electrons?
>       The latter ones can be directly obtained - all along
> the decay chain -
>       by implementing in the input file your Ra isotope as
> radioactive
>       source (BEAM/SDUM=ISOTOPE, HI-PROPE with respective
> Z and A,
>       RADDECAY/WHAT(1)=2.0 i.e. semi-analogue), with no
> need for the source
>       user routine.
>
>       Conversely, for the alphas - with the present FLUKA
> version - you
>       actually need to implement your source.f, which is
> more challenging.
>
>       3. source.f requires several variables (weight,
> polarization, ...) to
>       be set, but they are already filled by default, so
> you shall change
>       only the ones relevant to your case (i.e. the
> particle kinetic
>       energy/momentum)
>
>       2. decay spectrum data are available for instance at
>       http://www.nndc.bnl.gov/
>       An external file can be in whatsoever format, since
> it's up to you to
>       properly read its content inside source.f and
> appropriately store the
>       relevant info.
>
>       1. if you are interested in sampling decay alphas,
> you should set in
>       the BEAM card 4-HELIUM as beam particle and assign
> in source.f its
>       kinetic energy and momentum according to your data,
> selecting a fixed
>       experimental energy value on the basis of the
> respective branching
>       ratio. This requires some programming skills.
>
>       Kind regards
>
>       Francesco
>
>       **************************************************
>       Francesco Cerutti
>       CERN-EN/STI
>       CH-1211 Geneva 23
>       Switzerland
>       tel. +41 22 7678962
>       fax  +41 22 7668854
>
>       On Sun, 1 Oct 2017, Agnieszka Witkowska wrote:
>
>             Dear Fluka Users,
>             I am the beginner in terms of Fluka usage and
> I am trying
>             to implement spectrum of radium
>             as a beam by using user routine source.f. I
> have read
>             manual and Fluka courses
>             presentations, however it is still not clear
> for me how to
>             implement such feature. Can You
>             please help me with questions below?
>
>             1. How to assign beam to the data read from
> the file?
>             2. Can You please advise where can I find
> files with
>             spectrum properties? As I understand
>             files which can be included in source routine
> should be in
>             collision type?
>             3. I would like to modify only the energy of
> the beam to
>             create spectrum as a source. Do I
>             have to include in the source routine other 
> parameters
>             definitions like weight of the
>             particle, polarization etc. or I can omit them
> and the
>             routine will work?
>
>             Thank You for your help in advance.
>
>             Best regards, 
>             Agnieszka Witkowska
>
>
>
>
>
>

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Received on Thu Oct 05 2017 - 00:32:58 CEST

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