Re: Defining a radioactive isotope as source

Dear Sebastien,

Thank you for your help.

I actually do have a RADDECAY card in the input. It is the following:

RADDECAY 1. 3. 0.0 1000010

I also have set production and transport cuts to 20 keV for gammas, e+/e-. but I still don't see any interactions.

The very fact that a RADDECAY card is necessary for a radioactive source implies that the two methods are handled
differently (internally) by the code. So it doesn't seem like the ISOTOPE under the question is looked up to see
whether it is radioactive or not and if so, an average for main emitted gamma energies are used to generate
interactions. Can one of the FLUKA gurus shed some light on this by commenting on how a radioactive source is
implemented and why is it that I am not seeing any interactions?

Looking in the manual Under BEAM --> SDUM, I see:

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.

There is no mention of a RADDECAY card inclusion.
The only example on a radioactive source is for Cs-137.

* The next BEAM card describes a 137-Cs isotropic source
BEAM -661.7E-6 0.0 1.E4 0.0 0.0 1.0 PHOTON

Thank you very much and best wishes,
Mina

On 12-04-26 01:02 AM, wurth_at_ipno.in2p3.fr wrote:
> 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 Fri Apr 27 2012 - 00:36:51 CEST