Recent Improvements in Beam Delivery with the TRIUMF’s 500 MeV Cyclotron
Bibliographic record
Abstract
TRIUMF’s 500 MeV H⁻ Cyclotron, despite its 44 years age is under continuous development. Many aspects of beam delivery have been improved over the last few years. Regular 3-week cusp source filament exchange cycle has advanced to multi-months due to greatly improved filament life time. Fine source tuning allowed beam intensity rise in support of routine extraction of 300 uA of protons. The injection line model has been fully correlated with online measurements that enabled its tuning and matching to the emittance defining slits and the cyclotron entrance. Cyclotron routinely produces 3 simultaneous high intensity beams (~100 uA each). Multiple techniques have been developed to maintain extracted beams intensity stability within ± 1%. Record extraction foil life times in excess of 500 mA-hours have been demonstrated with highly-oriented pyrolytic graphite foil material and improvements in foil holder. Beam rastering on ISOL target allowed higher yields. A single user extraction at 100 MeV was achieved by applying phase slip and deceleration inside the cyclotron.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".