CCRI.RI(II)-K2.Pa-231 Key Comparison of activity measurements of the radionuclide 231Pa
Bibliographic record
Abstract
Main text The introduction over the last decade of radionuclide therapy based on 223Ra and 227Th has reawakened interest in the radionuclides of the 235U decay series (the 4n+3 decay chain). This has coincided with a requirement for improved accuracy in dating of long-lived radionuclides for nuclear forensic and for geological purposes. Thus, 231Pa has become the subject of revived interest in recent years. The short-term ingrowth of the decay progeny is of interest to nuclear forensic science since it enables the direct calculation of the separation age of enriched 235U[1]; separation times based on the 234U-230Th chain may also be calculated, but are more complex due to the reliance on the 238U-234Th-234mPa-234U-230Th decay family. Furthermore, since protactinium fluorides are non-volatile at ordinary temperature, the build-up of 231Pa in fuel enrichment facilities may provide information on throughput of separation units as well as the whole plant. In the longer term, the characterisation of sedimentation rates is facilitated by a range of natural nuclear chronometers that include 231Pa/235U to provide information concerning sediment formation, and the measurement of 231Pa:230Th mass ratios (as well as 231Pa:235U and 230Th:234U mass ratios) may also provide information of global temperature trends over the 100-200 ka range[2]. This report summarises the results of an international comparison of the activity per unit mass of the same 231Pa solution along with a new half-life determination[3]. To reach the main text of this paper, click on Final Report . Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/ . The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.534 | 0.591 |
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".