I calculated the dose rate of an isotopic source and obtained the expected results when testing an isotropic shield. nuclide.flair (3.5 KB) nuclide_24_sum.lis (32.3 KB)
However, when I changed the geometry, I got incorrect results. I verified this using other software with the same geometry. The input file and results are as follows: gutter.flair (2.6 KB) gutter_21_plot.dat (13.7 KB) gutter_22_plot.dat (4.3 KB)
I don’t know where my mistake is.
Looking forward to your reply.
Best regards,
Ding
Could you please elaborate where your mistake is? it is not very clear from the question you posed or the files you provided. I did a few initial checks on my side, is the issue in your DOSE-EQ scoring? When comparing the two input files, it looks like for the DOSE-EQ scorings in the “nuclide” case you requested Region scoring and in the “gutter” case you use Cartesian binning scoring.
Cheers, please reach back out in case you run into trouble,
Yes, the DOSE-EQ score in the “gutter” case is excessively high, whereas the result in the “nuclide” case aligns with expectations.
For example, in the “gutter” case, at 50 cm above the ground directly over the gutter, the unnormalized expected result should be around 1E-8, but the current calculated value is 6.123326602E-05. After normalization, this becomes over 1000 times higher than the MCNP result for the same model and location.
Since the result in the “nuclide” case is reasonable, but the “gutter” case shows significant deviation, I’m unsure whether there might be an error in my statistical approach.
Hello @dingyuan1991 , as suggested in my reply above and to be sure: are you now comparing in both cases the same scoring for DOSE-EQ? I.e., region-by-region OR cartesian binning? Since in the input files you provided in the “nuclide” case you requested region scoring for the DOSE-EQ and in the “gutter” case you requested Cartesian binning.
Yes this is indeed why I am worried that your direct comparison between the two cases will not work. Please note, as explained in the manual entry for USRBIN and exemplified in this post that “The results from USRBIN are normalised per unit volume and per unit primary weight, except region binnings and special user-defined binnings, which are normalised per unit primary weight only,”. I don’t see you applying the correct normalisation in the flair file for the case where you use region binning.
Hope this puts you in the right direction,
Cheers,