Re: Fluka for internal dosimetry

From: Stefan Roesler <>
Date: Sun, 6 Sep 2009 13:31:35 +0200

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).


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
> CH-1211 Geneva 23
> Switzerland
> tel. ++41 22 7678962
> fax ++41 22 7668854

Stefan Roesler
CH-1211 Geneva 23
Phone:  +41-22-7679891
Fax:    +41-22-7669639
Received on Sun Sep 06 2009 - 16:19:45 CEST

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