Nuclear moments of the radioactive isotope 131La determined by collinear fast-beam laser spectroscopy
Bibliographic record
Abstract
We report on our first measurements with collinear fast-beam spectroscopy at the ISAC facility at TRIUMF (Canada). This nuclear facility is able to produce intense beams of radioactive isotopes of the rare earth elements with unprecedented intensities. In particular the neutron deficient region below the N=82 shell closure is of interest and contains around N=74 an unexplored region of nuclear deformation predicted both by the Finite-Range Droplet Model (FRDM) and the Hartree-Fock-BCS method. These calculations do not include the triaxial degree of freedom. However, also triaxiality or γ-softness is predicted theoretically to play an important role in the nuclei of the low Z elements in the rare earth region N=74. The nuclear moments and changes in nuclear charge radii provide sensitive information on nuclear deformation. So far only a few rare earth isotopes below shell closure could be investigated with laser spectroscopy. This is due to the low production yields, which require large proton beam currents for the sufficient production of radioactive isotopes in this region. In this paper, we report preliminary measurements of the HFS constants of 131La (N=74) as an initial step to further exploring this region. The nuclear moments are extracted from the data and compared with predictions from the above listed theoretical models. our work is an extension of our earlier off-line experiments on 135,137-139La at JAEA (Japan) to on-line laser spectroscopy.
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How this classification was reachedexpand
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".