Hi Chris
The threshold as such is there to limit the output to nuclides of
significant activities. Of course, what is "significant" depends on the
application...
I don't think there is any reasoning behind that particular threshold
value. Thus, the user should (be aware of the existence and) modify to any
value more reasonable if necessary.
(Paola please correct if I am wrong)
Cheers
Stefan
On Thu, 3 Mar 2011, Chris Theis wrote:
> Dear colleagues,
>
> in the course of some recent activation studies we noticed that using USRSUWEV
> to calculate activity offline yields slightly different results in terms
> of nuclide yield in comparison to an online calculation with FLUKA. Some
> investigation showed that in the post-processing a filter is applied by
> setting a threshold of 0.1% of the total activity:
>
> THRESH =3D TOTTOT(NRN) * 0.001
>
> I would like to understand the reasoning for this threshold because on one hand
> it means that the results of a direct FLUKA output and an off-line result
> are not consistent. I'm fully aware the extremely low contributions like
> activities in the order of 1e-100 are of arguable meaning. Yet, the results
> are still inconsistent and it's not clear to me why the filter is applied
> only for the creation of the "_res.lis" file.
>
> On the other hand I would also like to understand the reasoning for setting
> the threshold value at 0.1%. If one looks at the clearance values for different
> isotopes they can differ by several orders of magnitudes (e.g. from 2 to
> almost 1e7) and thus, nuclides of rather low activity could still be important
> from a radiological point of view. Looking at the range of the clearance values
> the threshold at 0.1% seems high to me, but probably there is some reasoning
> behind that I'm missing here. I would appreciate if some of the developers could
> comment on this.
>
> Thanks a lot
> Chris
>
>
>
>
Received on Fri Mar 04 2011 - 15:37:18 CET
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