Re: Fluka for internal dosimetry

Dear Ernesto

I'd like to add that in your case you may want to set IRRPROFI and
DCYTIMES as follows

IRRPROFI 1.E10 1.0
DCYTIMES -100.0 [tdec]

In 'normal' activation calculations IRRPROFI determines the production of
radioactive nuclides and DCYTIMES the point in time at which you want to
calculate quatities.

If I understand correctly in your case you would like to start from a
radioactive isotope of a certain activity. The above would be equivalent
to saturation in the creation of the nuclide (very long irradiation time
of 1E10seconds), at 1 nuclide per second (or 1Bq since at saturation
production rate=decay rate).

As for the decay time, if you just want to start from 1Bq of a certain
source (and apply any further normalization offline) you can do it by
defining a (arbitrary) negative decay time. On the other hand if you would
like to do a simulation for a real radioactive source with a specified
activity at a certain date you can do this by defining a positive decay
time [tdec] being equal to the time difference between the specified date
and the date for which you want to simulate it (FLUKA would then calculate
the decay for you).

Cheers
Stefan

On Fri, 4 Sep 2009, Francesco Cerutti wrote:

>
> Dear Ernesto,
>
> > 1. Is it possible to choose the radioisotope from a list (for example
> > the periodic table) and to define it as a "source", or any emitted
> > radiation (beta, gamma, ...) must be separately inserted as primary
> > particles to be tracked?
>
> in fact you can input as primary particle a radioisotope and let it decay by
> switching on the decay treatment through the RADDECAY card. You can define its
> production rate over a given time interval through IRRPROFIle and have a look
> at the quantities of your interest at any time - predefined through DCYTIMES -
> , by linking the respective scoring detectors to a given 'cooling' time
> through DCYSCORE.
> Quoting from the manual (BEAM card):
> "For (radioactive) isotopes, use the name ISOTOPE and specify further the
> isotope properties by means of option HI-PROPErt.
> In this case WHAT(1) and WHAT(2) are meaningless. If no radioactive isotope
> evolution or decay is requested, or if a stable isotope is input, nothing will
> occur, and no particle will be transported."
>
> > 2. How to simulate an homogeneous distribution of radionuclides in a
> > volume? Is it possible to use BEAM and BEAMPOS cards, or is it necessary
> > to implement a user SOURCE code?
>
> For a homogeneous distribution over a volume, you need to go through the
> source user routine.
>
> All the best
>
> Francesco
>
> **************************************************
> Francesco Cerutti
> CERN-EN/STI
> CH-1211 Geneva 23
> Switzerland
> tel. ++41 22 7678962
> fax ++41 22 7668854
>
>

-- 
___________________________________
Stefan Roesler
CERN, DG-SCR
CH-1211 Geneva 23
Switzerland
Phone:  +41-22-7679891
Fax:    +41-22-7669639
E-mail: Stefan.Roesler_at_cern.ch