Determining the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow/><mml:mn>239</mml:mn></mml:msup></mml:math>Np<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mo>(</mml:mo><mml:mi>n</mml:mi><mml:mo>,</mml:mo><mml:mi>f</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:math>cross section using the surrogate ratio method
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Background: Neutron-induced fission cross-section data are needed in various fields of applied and basic nuclear science. However, cross sections of short-lived nuclei are difficult to measure directly due to experimental constraints.Purpose: The first experimental determination of the neutron-induced fission cross section of ${}^{239}$Np at nonthermal energies was performed. This minor actinide is the waiting point to ${}^{240}$Pu production in a nuclear reactor.Method: The surrogate ratio method was employed to indirectly deduce the ${}^{239}\text{Np}(n,f)$ cross section. The surrogate reactions used were ${}^{236}\text{U}{(}^{3}\text{He},p)$ and ${}^{238}\text{U}{(}^{3}\text{He},p)$ with the reference cross section given by the well-known ${}^{237}\text{Np}(n,f)$ cross section. The ratio of observed fission reactions resulting from the two formed compound nuclei, ${}^{238}$Np and ${}^{240}$Np, was multiplied by the directly measured ${}^{237}\text{Np}(n,f)$ cross section to determine the ${}^{239}\text{Np}(n,f)$ cross section.Results: The ${}^{239}\text{Np}(n,f)$ cross section was determined with an uncertainty ranging between 4$%$ and 30$%$ over the energy range of 0.5--20 MeV. The resulting cross section agrees closest with the JENDL-4.0 evaluation.Conclusions: The measured cross section falls in between the existing evaluations, but it does not match any evaluation exactly (with JENDL-4.0 being the closest match); hence reactor codes relying on existing evaluations may under- or overestimate the amount of ${}^{240}$Pu produced during fuel burnup. The measurement helps constrain nuclear structure parameters used in the evaluations.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.003 |
| Meta-epidemiology (narrow) | 0.003 | 0.004 |
| Meta-epidemiology (broad) | 0.001 | 0.005 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.004 | 0.002 |
| Scholarly communication | 0.004 | 0.004 |
| Open science | 0.004 | 0.004 |
| Research integrity | 0.003 | 0.005 |
| Insufficient payload (model declined to judge) | 0.005 | 0.005 |
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 it