[fluka-discuss]: resnuclei scoring - some issues

From: Benmerrouche, Mohamed <Benmerrouche_at_bnl.gov>
Date: Fri, 2 Oct 2020 01:24:37 +0000

Dear Fluka experts,

I came across some issues with the resnuclei scoring output. All the comparisons I discuss below are for 1s decay time and based on FLUKA version 2020.0.3.

1. The activities of individual isotopes given in rsncle_40_tab.lis do not add up to the value given in rsncle_40_sum.lis. For example activity produced in detector TG1_1s at 1s decay time : 1.65E+16 Bq +/- 19.1% (from rsncle_40_sum.lis). If I add up the activities of all radionuclides (including isomers) listed in rsncle_40_tab.lis and subtract from the above sum value I obtain 2.8516E+11 but shouldn't be zero?

2. As an alternative to scoring radionuclides at various decay times within fluka input file (online) one can also score them offline using RESNUCLE without assigning any decay time and usrsuwev.f. The results of this process for various decay times is given in file sum_30-evo_res.lis. The sum of all activities at 1s decay time is 1.4754E+14 Bq +/- 3.5E-02 %, which is quite different from the value given above from online scoring [Note the statistics are much lower than given above]. Also the activity for the isomer Ge(A=37,Z=32,m=1) is 1.633E+16 Bq from online while it is much less using offline processing with a value of 1.400E+14 Bq. There are also a number of isotopes produced online compared to offline such as
67 32 2.2830E+05
69 33 2.2827E+05
51 22 2.2798E+05
23 10 2.2423E+05
10 6 2.2038E+05
20 8 2.1702E+05
21 12 7.7860E+02
59 28 4.5635E-02
13 5 9.7346E-13

The above values do have 99% statistical errors. For the offline scoring, the difference between the sum given sum_30-evo_res.lis and adding activities of isotopes (including isomers) is off by -2.6118E+08!
So is offline processing equivalent to online? If not please explain with examples if possible. The offline processing is very useful as it does not require to run fluka any time one require radionuclides inventory and associated activities at some other irradiation times and cooling times! So is it reliable to use it?

3. The following statement in usrsuwev.f should be revised for example if I enter the default "no" the LPATCH will evaluate to T and if I enter "yes" it will evaluate to F.

      WRITE (*,*)' Do you want to patch isomers (def=no)?'
      READ (*,'(A)') YES
      LPATCH = YES .EQ. 'Y' .OR. YES .NE. 'y'

In the previous version of FLUKA 2011-2x-8 it was :

      WRITE (*,*)' Do you want to patch isomers (def=yes)?'
      READ (*,'(A)') YES
      LPATCH = YES .NE. 'N' .AND. YES .NE. 'n'

My input file, rsncle_40_sum.lis , rsncle_40_tab.lis, and sum_30-evo_res.lis are available via the link

Let me know if additional info is required. Thank you for your help and support,

Dr. M. Benmerrouche, Ph.D., M.Sc., B.Sc.
Radiation Physicist
Brookhaven National Laboratory
Building 745
P.O. Box 5000
Upton, NY 11973-5000
Tel: 631-344-2068
Email: benmerrouche_at_bnl.gov

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Received on Fri Oct 02 2020 - 05:53:53 CEST

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