The PS 40 MHz bunching cavity
Bibliographic record
Abstract
A 40 MHz cavity has been designed and built at CERN as part of the preparation of the PS as injector for LHC. The cavity will provide the necessary bunch spacing of 25 ns prior to injection into SPS and subsequently LHC. The mechanical design of the copper coated steel cavity was dominated by space constraints in the PS tunnel and by vacuum requirements. The salient design features described are (i) tight, multipactor-free, capacitive coupling from the power amplifier, (ii) fast RF feedback, (iii) inductively coupled tuners, (iv) an efficient, pneumatically operated gap short-circuit. The operation cycle consists of an adiabatic capture up to 100 kV gap voltage, a non-adiabatic jump to 300 kV, and subsequent bunch rotation. The multipactor voltage level at the gap lies below the operating voltage range and is easily passed through. A fast RF feedback system with a total group delay of 220 ns copes with heavy beam loading (10/sup 11/ protons/bunch) and prevents unwanted interaction with other beams in the PS. The cavity has recently been installed, the nominal gap voltage of 300 kV has been attained, and bunch lengths below 8 ns have been achieved in first tests at nominal intensity. Experimental results are reported.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.010 | 0.002 |
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".