International comparisons of He-Ne lasers stabilized with<sup>127</sup>I<sub>2</sub>at 633 nm (July 2000). Part X: Comparison of INMETRO (Brazil), INTI (Argentina), NRC-INMS (Canada), CENAM (Mexico), and BIPM lasers at 633 nm
Bibliographic record
Abstract
This paper reports the tenth set of results of a series of grouped laser comparisons from national laboratories undertaken by the Bureau International des Poids et Mesures (BIPM) at the request of the Consultative Committee for Length (CCL), formerly the Consultative Committee for the Definition of the Metre (CCDM), for the periods July 1993 to September 1995 and March 1997 to March 2001. As with the previous nine comparisons, this one is expected to be listed as a key comparison in the context of the ongoing BIPM.L-K10 series. The results of this comparison, involving seven lasers from four countries in the Americas and the BIPM, meet the goals set by the CCDM in 1992 and in 1997 and adopted by the International Committee for Weights and Measures (CIPM) the same year. The standard uncertainty (1σ) of the frequency of the He-Ne laser stabilized on the saturated absorption of 127 I 2 at λ ≈ 633 nm is reduced to a level of 12 kHz (2.5 parts in 10 11 ) when the lasers compared meet the recommended values of the parameters. The lasers were first compared with the BIPMP3 laser, with all the lasers set to the parameter values normally used in each laboratory; the results then ranged from -31.5 kHz to +10.0 kHz. After checking and correcting when possible the values of all the parameters, the range stayed about the same, -31.5 kHz to +9.1 kHz. Under the latter conditions, the average frequency difference of the group of seven lasers, with respect to the BIPM4 laser, was -4.4 kHz with a standard uncertainty (1σ) of 13.2 kHz. If the INMETRO2 laser, considered as a secondary laser, is removed from the group, then the average is -0.5 kHz with a standard deviation (1σ) of 9.2 kHz. The best relative frequency stabilities, with Allan standard deviations of about 9.3 × 10 -13 , 3.5 × 10 -13 and 1.4 × 10 -13 , were observed with sampling times of 10 s, 100 s and 1000 s, respectively. Results obtained with NRC and BIPM lasers over a period of five months in two beat-frequency laser comparisons and in an absolute frequency measurement lie within 1 kHz (2 parts in 10 12 ).
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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 | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".