Measurement of the space charge effect of a negative hydrogen ion beam
Bibliographic record
Abstract
A source of epithermal neutrons based on a vacuum-insulated tandem accelerator and a lithium target is developed for the technique of boron neutron capture therapy. A 2 MeV stationary proton beam with a current of up to 5 mA was obtained in the accelerator. With a view of increasing the current, the transport of a beam of negative hydrogen ions from the ion source to the accelerator is studied using a wire scanner OWS-30 (D-Pace, Canada) and a movable diaphragm. Dependences of the ion beam profile and the current on the residual gas pressure are measured and the influence of the space charge is detected. We measured the phase portrait of the beam in the radial and azimuth directions and discovered the effect produced by the aberrations of the focusing magnetic lens. We also gaged the value of the normalized beam emittance. The change in beam focusing mode and the introduction of optical diagnostics of the beam position in the diaphragm of the first accelerating electrode made it possible to significantly improve the stability of the accelerator operation at high current of the proton beam, up to 6.7 mA.
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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 | 0.001 | 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".