Resonance neutron-capture cross sections of stable magnesium isotopes and their astrophysical implications
Bibliographic record
Abstract
We have measured the neutron capture cross sections of the stable magnesium isotopes ${}^{24,25,26}$Mg in the energy range of interest to the $s$ process using the neutron time-of-flight facility n_TOF at CERN. Capture events from a natural metal sample and from samples enriched in ${}^{25}$Mg and ${}^{26}$Mg were recorded using the total energy method based on C${}_{6}$${}^{2}$H${}_{6}$ detectors. Neutron resonance parameters were extracted by a simultaneous resonance shape analysis of the present capture data and existing transmission data on a natural isotopic sample. Maxwellian-averaged capture cross sections for the three isotopes were calculated up to thermal energies of 100 keV and their impact on $s$-process analyses was investigated. At 30 keV the new values of the stellar cross section for ${}^{24}$Mg, ${}^{25}$Mg, and ${}^{26}$Mg are 3.8$\ifmmode\pm\else\textpm\fi{}$0.2 mb, 4.1$\ifmmode\pm\else\textpm\fi{}$0.6 mb, and 0.14$\ifmmode\pm\else\textpm\fi{}$0.01 mb, respectively.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".