Re: [fluka-discuss]: Cards needed for isotopes

From: Mikhail Polkovnikov <>
Date: Thu, 23 Jun 2016 19:37:21 +0300

On 23.06.2016 16:14, Keith Welch wrote:
> Joachim and Mikhail,
> Thanks very much for your answers. I think the idea of individual
> runs (first approach) would be easiest for me. But I'm still confused
> about the spacial distribution issue. This is maybe a very elementary
> question, but I am just a novice user. If I have a radionuclide in
> five different locations, and each location is a simple cartesian
> volume, how do I designate the BEAMPOS cards to define these five
> volumes? Simply by sequence?
> Thanks again,
> Keith
> ------------------------------------------------------------------------
> *From: *"Joachim Vollaire" <>
> *To: *
> *Sent: *Thursday, June 23, 2016 6:15:50 AM
> *Subject: *RE: [fluka-discuss]: Cards needed for isotopes
> Hi Keith
> 1) First approach
> If you limit yourself to the built-in source specifications
> capabilities then you can only request to simulate the decay of a
> single type of isotope as primary particles. With this approach then
> you would need for each type of isotope to run a different type of
> simulations. As I understand from your email to the list that you have
> 6 isotopes, then you would need 6 different inputs where you would
> specify for each the source details (concerned isotope, spatial
> distribution BEAM – BEAMPOS…)…
> Then there is some post-processing work to be done as with flair you
> can plot the results showing the results for a single isotope (which
> you should normalize to the activity for that specific isotope in your
> mixture…). I don’t know any straightforward way to merge for example
> dose rate maps with flair, but you can have a look at my reply a few
> weeks ago to a person with a similar question for adding different runs.
> Be careful however not to merge outputs corresponding to different
> isotopes with the FLUKA / flair tools (usbsuw) as first the calculated
> statistical uncertainty would have no meaning (based on the
> distribution of score corresponding to different physics case…) and
> second you would not be able to weight/normalize the different
> contributions to the activity of each isotope….
> 2) Second Approach
> You use the source routine (SOURCE card) to call the routine each time
> the code needs to start a primary particle. You need to write your own
> source.f routine and create a new executable. You could read the
> information on your isotope at initialization for example in a data
> file (6 lines, Z = xx A = yy Activity/fraction = xx) and sample based
> on this distribution. You need to specify the IJHION value in the
> routine (look at the part of the routine concerning Radioactive Isotope…)…
> Either you give each isotope a weight equal to unity and you sample
> based on the probability function (partial activity fraction) or you
> sample with the same probability each isotope but you adjust the
> weight based on the partial activity fraction. At the end the
> normalization will be done using the WEIPRI (total weight of primary
> particles generated)… The results will be normalized to one Bq of
> activity in your system (thus you need to normalize to the total
> activity considering each isotope…). For the spatial distribution you
> can use the BEAM / BEAMPOS parameters or write your own logic based on
> the sample isotope in case
> Personally I would go with the first approach as at the end you have
> more information (individual contribution of each isotope….) which
> could be re-used if you are changing your mixture activity as the
> normalization is done at the post-processing level and there is less
> chance of user error in writing the source routine. Now if you have a
> (more) complicated mixture with complex a spatial distribution in
> maybe it is mandatory to use the source routine…
> Cheers
> Joachim
> -----Original Message-----
> From:
> [] On Behalf Of Mikhail
> Polkovnikov <?????? ???????????>
> Sent: 23 June 2016 09:26
> To: Keith Welch <>;
> Subject: Re: [fluka-discuss]: Cards needed for isotopes
> On 22.06.2016 04:41, Keith Welch wrote:
> Dear Keith,
> > 1. Do I need a separate BEAM card for each isotope in the material?
> > And/or separate BEAM card for each of the CART-VOL source regions?
> > (If so, does each beam card need its own physics, start, etc. cards?)
> > 2. Do I understand correctly that I need
> You need only one BEAM, HI-PROPE pair of cards if you use only one
> isotope (nuclide), for example Co-60 will have:
> *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....
> BEAM 10000.0 -1.0ISOTOPE
> HI-PROPE 27. 60.
> > 2 BEAMPOS cards to describe the distribution of the material in each
> > CART-VOL region? One that defines the volume and one that defines the
> > point around which the volume is centered?
> >
> Yes.
> > 3. Is it even possible to do this in one setup? Do I have to perform
> > different models for each single isotope and region and then combine
> > them? Or is there a better method, like SOURCE cards?
> It's possible, but i think you will have to use preprocessor to define
> different volume, position, material and region of your sources, e.g.
> if you have trace amounts of Co-60 dissolved in water as a first
> source and a chunk of cobalt metal as a second source. Both of these
> sources have the same primary particles ( gammas from Co-60 decay),
> but different types of source material, region, volume and activity.
> Best regards,
> Mikhail
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Dear Keith,

My example can be raw and inaccurate!

The simple test with two sources is in attachment. There are two input
files (isotope-1.inp, isotope-2.inp) will be created by Flair if in Run
page you will start isotope-1 (uses #define S1) and isotope-2 (uses
#define S2).

Then you can merge the data from both inputs in one single file.

Best regards,


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Received on Thu Jun 23 2016 - 21:12:50 CEST

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