Enhancement of the positive secondary ion yield during low‐energy, dual‐beam depth profiling of polytetrafluoroethylene with 1‐keV Cs <sup>+</sup>
Bibliographic record
Abstract
Abstract This work documents the behaviour of the positive secondary ion yield of bulk polytetrafluoroethylene (PTFE) under dual‐beam depth profiling conditions employing 1 keV Ar + , Cs + and SF 5 + . A unique chemical interaction is observed in the form of a dramatic enhancement of the positive secondary ion yield when PTFE is dual‐beam profiled with 1 keV Cs + . The distinct absence of such an enhancement is noted for comparison on two non‐fluorinated polymers, polyethylene terephthalate (PET) and polydimethylsiloxane (PDMS). The bulk PTFE was probed using 15‐keV, 69 Ga + primary ions in dual beam mode under static conditions; 1‐keV Ar + (a non‐reactive, light, noble element), Cs + (a heavier metallic ion known to form clusters) and SF 5 + (a polyatomic species) served as the sputter ion species. The total accumulated primary ion dose was of the order of 10 15 ions/cm 2 , which is well beyond the static limit. The enhancement of the positive secondary yield obtained when profiling with 1‐keV Cs + far exceeds that obtained when SF 5 + is employed. An explanation of this apparent reactive ion effect in PTFE is offered in terms of polarisation of CF bonds by Cs + in the vicinity of the implantation site thereby predisposing them to facile scission. The formation of peculiar, periodic Cs x F y + (where y = x − 1) and Cs x C y F z + clusters that can extend to masses approaching 2000 amu are also observed. Such species may serve as useful fingerprints for fluorocarbons that can be initiated via pre‐dosing a sample with low‐energy Cs + prior to static 15‐keV Ga + analysis. Copyright © 2005 John Wiley & Sons, Ltd.
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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 | 0.000 |
| 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) | 0.001 | 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 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".