Re: Defining a radioactive isotope as source

Dear Mina,

"If no radioactive isotope evolution or decay is requested [...]"
This means that you have to activate since it is not by default the
radioactive decay with a RADDECAY card.

But after trying with Joachim's set of cards I also don't get anything
unless I add an IRRPROFI card and at least a DCYTIMES (negative) to be
associated with a DCYSCORE applied to a detector card (say USRBIN,
USRTRACK). Then it goes OK, if scoring photon fluence in a proper USRTRACK
card I get the two photon peaks.
It challenges what I thought have been learned yesterday.

Best regards.
Sebastien.

> 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 - 13:04:00 CEST