Fix/urr background

[whaeck]

Background cross section values for reactions other than total, elastic, fission and capture were not handled properly in the unresolved resonance region. The background for total, elastic, fission and capture is integrated into the unresolved resonance cross section values in the genunr subroutine. In the emerge subroutine, the background in the unresolved resonance region was therefore zeroed out for any resonance reaction. This has never been an issue but now we have LRF=7 evaluations that can define reactions other than total, elastic, fission and capture. Test 82 was added to detect this issue in the future.

[kahlerac]

Hi Wim, Was just making a last minute check of email when I saw this. Sallie and I are on a plane early tomorrow (visiting family in Vermont and sight-seeing in Canada) and mostly out of touch until returning late Friday, August 9 (didn't want to say "8/9" in case you thought it might mean September 8!). If you can wait until after my return I'll do this, but if you want it sooner you'll need someone else. Looks like this patch may impact kcalc for some of the Mo containing benchmarks (some of HMF5, HMF84, maybe others?). Although I think 95Mo capture is the big xs for this nuclide. What do you think? And maybe keep Andrej in the loop also since he may want to make new ACE files. Skip

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On Tue, Jul 23, 2024 at 4:50 PM Wim Haeck ***@***.***> wrote: @whaeck <https://github.com/whaeck> requested your review on: #342 <#342> Fix/urr background. — Reply to this email directly, view it on GitHub <#342 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEHJISPH22GP5WT5C2VZGMDZN2627AVCNFSM6AAAAABLLFSL6GVHI2DSMVQWIX3LMV45UABCJFZXG5LFIV3GK3TUJZXXI2LGNFRWC5DJN5XDWMJTGYZDCNBQHAYTGNY> . You are receiving this because your review was requested.Message ID: ***@***.***>

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[whaeck]

We have time. The Mo95 evaluation that illustrates the issue is not in ENDF/B-VIII.1 and I don;t expect it to be adopted in time for the ENDF/B-VIII.1 release. If we can get this done by the end of September, I'm OK with it.

The missing xs values were of the order of microbarn so not that important either. However, I do not know how much this new evaluation would change the capture cross section with respect to the current ENDF/B-VIII.1b4 version.

[kahlerac]

With hindsight it's a simple fix, but something subtle that was easy to overlook during lrf=7 implementation ... good work!

[whaeck]

Lucky for us indeed :-)

Red pointed this issue out to me a few weeks ago. Took me a while to dig through the code to fix it, but it was an easy one.