Re: Defining a radioactive isotope as source

From: <wurth_at_ipno.in2p3.fr>
Date: Thu, 26 Apr 2012 10:02:02 +0200

Dear Mina,

I think you gave the answer yourself.
In order to activate the transport of your beampart which are the products
of the Co-60 disintegration you have to put at least a raddecay card.
Joachim wrote it in his "general comments" at the end of its answer.

By the way I learned something as well, I thought that an IRRPROFI card
was also mandatory in this case but it seems not, results will simply be
normalized per unit disintegration.

Best regards.

Sebastien.

> Dear Joachim, thank you for your response.
>
> I am taking baby steps in this regards...
> I get results from the 2nd method (can see beampart distribution for
> instance, etc).
> However, I can't get any reactions using the second method. I am using
> the following cards:
>
> BEAM 0.0 10000.0
> ISOTOPE
> * So an isotropic ISOTOPE beam. According to the manual, what(1) and
> what(2) are ignored.
>
> HI-PROPE 27.0 60.0
> * Defining Co-60
>
> BEAMPOS 0.0 0.0 0.0
> * Starting position of the beam (x,y,z : 0,0,0)
>
> BEAMPOS 0.0 1. 0.0
> SPHE-VOL
> * The source is uniformly distributed in a sphere of radius 1
>
>
>
> Why do I need to use a RADDECAY, DCYTIMES, DCYSCORE, if all I am
> interested (in the beginning) is to look at the
> beampart distribution?
>
> Are these necessary for production of the gammas from the decay of Co-60?
>
> Thank you and best wishes,
> Mina
>
>
> On 12-04-24 01:23 PM, Joachim Vollaire wrote:
>> Dear Mina,
>>
>> Here are some answers to your questions :
>>
>> 1) Does the first method, i.e. using the HI-PROPE option, do the same,
>> i.e. use isotropic and mono-energetic gammas with
>> energy as the average energy of (1332.5 keV and 1173.2 keV)?
>>
>> Yes in theory both approach should be the same if you are careful with
>> the normalization. Using the built-in source is however more
>> straightforward, especially for isotopes with many gamma lines... In the
>> case of Co you could do one photon run with one energy and another one
>> with the other line. As the results are normalized per primary, you
>> would need to add the scored quantity of the two runs and then multiply
>> per the Co60 activity as one disintegration leads to the production of
>> two photons....
>>
>> 2) Can the activity of the radioisotope be incorporated in the source
>> definition?
>> If you use the built-in source, the results are normalized to one
>> disintegration. This mean than when you post process the results you
>> have to normalize to the activity, as for a "prompt" calculation where
>> results are normalized to one primary particle....
>>
>> 3) Is it possible to define multiple radioisotopes as sources, taking
>> into account activities of each?
>>
>> The best is to run independent calculations for each isotopes, then
>> normalize to the corresponding activity (see 2) above) and add the
>> results....
>>
>> More general comment, you must not forget to call the particle decay
>> with RADDECAy for ISOTOPE used with the BEAM card. I have attached below
>> some cards taken from a calculations where I was looking at the dose
>> rate from Ar41 decay in air in a 300 X 300 X 300 cm3 room. The specific
>> activity in the air was equal to 70 kBq/m3, thus to get the results in
>> microSv/h the normalization factor I was using is the following :
>>
>> (3600/1.0e06)*3*3*3*70e3
>>
>> *
>> BEAM
>> 1.0ISOTOPE
>> BEAMPOS 0.0 300.0 0.0 300.0 0.0
>> 300.0CART-VOL
>> BEAMPOS 0.0 0.0 0.0
>> *
>> HI-PROPE 18. 41.
>>
>> RADDECAY 2.0
>> DCYSCORE -1.0 0. 0. DR-001 DR-001
>> USRBIN
>> *
>> *
>> USRBIN 10.0 DOSE-EQ -45.0 200.0 20.0
>> 200.0DR-001
>> USRBIN -200.0 -20.0 -200.0 100.0 1.0 100.0&
>>
>>
>> Hoping this help
>>
>> Joachim
>>
>> -----Original Message-----
>> From: owner-fluka-discuss_at_mi.infn.it
>> [mailto:owner-fluka-discuss_at_mi.infn.it] On Behalf Of Mina Nozar
>> Sent: 24 April 2012 03:12
>> To: fluka-discuss_at_fluka.org
>> Subject: Defining a radioactive isotope as source
>>
>> Hello everyone.
>>
>> I have a couple of questions in regard to how radioactive isotopes (as
>> sources) are handled in FLUKA.
>>
>> Looking through the "Sources" slides under
>> http://www.fluka.org/fluka.php?id=course&sub=program&navig=2&which=portugal2010
>>
>> To set up Co-60 as the radioactive source, it seems there are two
>> options.
>> One through the use of the "BEAM -> ISOTOPE" and "HI-PROPE -> Co-60
>> A,Z settings" and
>> another through the use of the "BEAM -> average energy for the two
>> main gamma energies emitted by Co-60".
>>
>> 1) Does the first method, i.e. using the HI-PROPE option, do the same,
>> i.e. use isotropic and mono-energetic gammas with
>> energy as the average energy of (1332.5 keV and 1173.2 keV)?
>>
>> 2) Can the activity of the radioisotope be incorporated in the source
>> definition?
>>
>> 3) Is it possible to define multiple radioisotopes as sources, taking
>> into account activities of each?
>>
>>
>> Thank you,
>> Mina
>>
>>
>
>
Received on Thu Apr 26 2012 - 10:39:53 CEST

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