Interpret and compare the output of RESNUCLEi and usrrnc.f

Dear professors,
I’m recording isotopes both with RESNUCLEi and usrrnc.f. However, there are several questions about their output.

  1. I have noticed that in this topic Interpretation of results from activation simulation - #3 by adonadon, @adonadon said that the RESNUCLEi gives me the activity. I wonder which line is the activity and which lines are dose per primary. I have uploaded the sum.lis and tab.lis for reference.
  2. How to obtain the whole yields of RESNUCLEi? I multiply each yield of isotope with the whole primaries(50000 in one cycle). Is that right?
  3. Both in the descriptions of RESNUCLEi and usrrnc.f, they said they will record whenever a residual nuclei stops. It confuses me in two ways. Firstly why not record when an isotope is produced which is a more straightforward way to yields. Secondly when elastic scattering occurs, this stopped nuclei is actually not “produced” and will there be double-counting?
  4. I am interested in two regions, water and LS. The RESNUCLEi is designed to record them respectively while usrrnc.f records them together. After postprocessing according to 2, I obtain the output of RESNUCLEi in LS. On the other hand, I collect the yields in usrrnc.f one by one. Only pay attentions to heavy isotopes like Te as there are no such isotopes in water, the output of the above two are supposed to be consistent. But it turns out to be significantly different. Why?
  5. For simplicity I only assign one cycle in each run. I’m not sure whether this will cause the problems in 4.

I have only uploaded one run among two thousands of the LS_tab.lis and usrrnc_output. The isomer-LS.txt and isotope-LS.txt are the whole results(1e8 primaries) after postprocessing. The second column is the result for RESNUCLEi while the third is for usrrnc.f.
Thank you for your help!
Best regards,
Hechong Han
isomer-LS.txt (2.0 KB)
isotope-LS.txt (6.8 KB)
LS_tab.lis (11.3 KB)
usrrnc_output.txt (3.8 MB)

  1. RESNUCLEi does not give dose per primary. It gives production yields or activities, as recently pointed out.
  2. The number of primaries has no physical meaning. You have to multiply by the real beam intensity to get sensible results.
  3. RESNUCLEi scores by region. If one nucleus is produced in one region but moves to another, it shall be scored in the latter. As for nuclear elastic scattering, see the release notes:
- Nuclear recoils with the same atomic and mass number as the target isotope
  (e.g. from (n,el), (n,n'), (p,p'), etc.) now contribute to RESNUCLEi scoring
  only when reaching a different geometry region.

So a pre-existing nucleus of a given material is counted as residual nucleus only when displaced to another region.
4. RESNUCLEi and usrrnc.f obviously give consistent results. If not, there is likely a problem in your routine or post-processing. The variable MREG enables the region distinction also in usrrnc.f. As earlier mentioned, a heavy isotope may be scored in water if it moves there. If you want to see where it was actually produced, you can use the last ENTRY of mgdraw.f.
5. To check the above consistency, it’s indeed convenient to run one single cycle.

Dear ceruttif,
Thank you for your detailed explanation! Point 3, 4 and 5 are now clear to me while I’m still confused with point 1 and 2. Let’s say I want to record the total number of certain isotope both with RESNUCLEi and usrrnc.f. Three cycles are completed for 1000 primaries each.

In RESNUCLEi, I will find the corresponding activity for this isotope A1, A2 and A3. The real beam intensity is N particles per second. So the total number is N times the average of A1, A2 and A3. Is that right?
In usrrnc.f, I can easily run over the output to collect this isotope according to its A, Z and M. The total number is just the number of findings after cycle. Is that right?

Thank you for your help!
Best regards
Hechong Han

If you want to compare RESNUCLEi and usrrnc.f output, just run one cycle (point 5 above) and ask for production yields, not activity (no DCYSCORE card). Then, for internal cross-checking, the real beam intensity is irrelevant: the total number of A,Z isotopes obtained from usrrnc.f should coincide with the RESNUCLEi A,Z value multiplied by the number of primaries of the run cycle.

Dear @ceruttif ,
I have restricted usrrnc.f to region 6(LS) according to your suggestions. The RESNUCLEi isn’t accompanied by DCYSCORE. However, I still find some inconsistency between RESNUCLEi and usrrnc.f. In a run of 50000 primaries, we obtain twenty six Te130 with no I130 and Xe130 from RESNUCLEi while twenty six Te130 with the same number of I130 and Xe130 from usrrnc.f. This is just an example of the breakdown in the crosscheck. The I130 and Xe130 must be the radioactive decay products of Te130.
My understanding is that the RESNUCLEi will not score the decay product without DCYSCORE. So if I am interested in the total production of isotopes, it’s better to use usrrnc.f?
I have uploaded the inp file and the output file both for RESNUCLEi and usrrnc.f. The first three columns represent A, Z and M respectively and the forth column is the region in fort.97.txt.
Te-LS001_fort.97.txt (466.3 KB)
LS_tab.lis (18.0 KB)
Te-LS.inp (3.3 KB)
Thank you for your help!
Best regards,
Hechong Han



No: since you are asking for radioactive decay in semi-analogue mode (which is not meant to be associated to any cooling time), RESNUCLEi will give you in this case the same production yields (and not activities) as usrrnc.f, including daughter nuclides, provided that you input a DCYSCORE card that is asking to include them in the RESNUCLEi output.
RESNUCLEi returns activities only when associated by DCYSCORE to a given cooling time, but this is not an option in case of radioactive decay in semi-analogue mode.

Thank you! I finally obtain the consistent results.