Radionuclide wise photon release rate after activation

Dear @adonadon

Continuing the discussion from Interpretation of results from activation simulation:

Just for future reference, I am attaching this journal paper. My intention was to explore if FLUKA can be used throughout the whole process mentioned in this attached journal (where they have used FLUKA for the first part and ORIGEN2 for the second part). I felt FLUKA could be more efficient tool for the second part also since it is already equipped with latest decay data and cross section data.

They have used ORIGEN and obtained the following result:

The main photon emitters are isotopes of W, Ta, Lu, Re, Yb and Hf, most of which have short half-lives and thus contribute little to photon emission after a comparatively long cooling time. For nuclides like 44Ti, 90Y, 157Tb, 94Nb, and their daughters, they contribute more than 90% to photon emission after a cooling time of 100 yrs, and the total photon release rate decreases about 5 orders of magnitude.

Hong_2016_Chinese_Phys._C_40_114102.pdf (981.3 KB)

Regards,

Riya

Dear @riya,

Thank you for the paper and the information.
Did you try what I proposed to you in the previous thread?

Best,
André

1 Like

Dear @adonadon ,

Sorry for the delayed response. I tried to follow the 2nd method. Is this what you meant ?? Here I have put A and Z for Mo which emits beta (for testing the usrrnc).

usrrnc.f (1.2 KB)

Dear @riya,

Yes, In that case you will ‘leave alive’ just those isotopes.
The contribution of any other isotope in the fluence calculation will not be considered.
I tried your code and it seems to be working fine for me, and you are doing correctly what I proposed to you. Very well done :slight_smile:

Let me know if you have any further questions.

Cheers,
André

Dear @adonadon ,

Thank you for confirming the routine. I have few questions regarding this routine.

  1. I have considered neutron fission of nat U. In the output of RESNUCLE card, all the fission products and their decay products are printed. If I use usrrnc.f in the simulation where I have filtered out A and Z of Mo 99, I am getting the same RESNUCLE output. What I assumed was after using usrrnc.f, now only Mo 99 activity will be printed. Hence, in this regard, my doubt is that is this usrrnc.f routine is getting activated if I use USRBDX or USRTRACK or USRBIN corresponding to irradiation and decay time only ? Is it not associated with RESNUCLE output ?

  2. Suppose, I want to get gamma for Tc 99m only. In that case, Z = 43, A = 99. What should I put for the meta stable state in usrrnc.f ? Does “IS” parameter play a role here ?

  3. It will be helpful if you can direct me to the manual describing the various parameters in usrrnc.f to learn more about these parameters.

Regards,
Riya

Dear @riya,

  1. Yes, what you are assuming is correct, you should just get a peak in the RESNUCLE. It means that you are probably missing something in your input. Possibilities:
  • Are you using the USERWEIG card with USRRNC option?

https://flukafiles.web.cern.ch/manual/chapters/user_routines/user_routines/usrrnc.html?highlight=usrrnc

  • Are you compiling properly fluka with your routine?
  1. Yes, you have to get the IS = 1 to obtain the Tc 99m.

  2. It is in the link I added above :slight_smile:

Best,
André

Ok, I found the problem. Actually there is an error in your routine.

Try again using this routine modified

usrrnc.f (1.2 KB)

Cheers!
André

1 Like

Hi @adonadon ,

I have used the above routine. Can you please check if the USERWEIG setting is added properly ?

I have observed a few things:

  1. With and without USRRNC.f, the Mo activity is different. Is it because if we use a filter of Mo at usrrnc.f, no other residual nuclide will produce ? What I assumed was the usrrnc only acts as a filter for printing the output. If it is not the case, then higher value of Mo activity without usrrnc.f is due to neutron fission of U235 as well as other pathway of Mo production (i.e. either radioactive decay of other fission products yielding to Mo 99 or neutron activation of other fission products yielding to Mo99). Using Mo 99 filter in usrrnc.f, it is actually stopping these other production pathways of Mo99 and only fission of u235 is happening. Is it the case here?

  2. The error in activity is higher if usrrnc.f is used. Is there any reason for that? I have used same history in both the cases.

  3. If I want to apply usrrnc.f to my USRBIN or USRTRACK or USRBDX output, should I use the same settings in USERWEIG ?? I have gone through the above link, but it was not very clear to me.

  4. With usrrnc.f, why some radionuclides other than Z = 42 are getting printed in output ??

I am attaching the input files for your convenience. Also, I am attaching the two outputs with and with out usrrnc.f . Hope I have conveyed my doubts properly.

WithOUT_USRRNC

With_USRRNC

Mo_prod_ads_lv.inp (2.6 KB)
Mo_prod_ads_lv.flair (2.7 KB)
source_newgen_ads.f (18.7 KB)
usrrnc.f (1.2 KB)

Regards,

Riya