Single-ion mass spectrometry at 100 ppt and beyond
Bibliographic record
Abstract
Using a Penning trap single-ion mass spectrometer, we measured the atomic masses of 14 isotopes with a fractional accuracy of ~1010. The precision on these measurements was limited by the temporal fluctuations of our magnetic field. By trapping two different ions in the same Penning trap at the same time, we have recently been able to virtually eliminate that source of error. We can now simultaneously measure the ratio of the two ion's cyclotron frequencies (from which we obtain their atomic mass ratio) with a precision of about 1011 in only a few hours. To perform these comparisons, we must be able to measure and control all three normal modes of motion of each ion cyclotron, axial, and magnetron and have developed novel techniques to do so. This new technique shows promise of expanding the precision of mass spectrometry by an order of magnitude beyond the current state-of-the-art. PACS Nos.: 32.10Bi, 06.20Jr, 06.30Dr, 07.75+h, 07.77-n
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.011 | 0.006 |
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".