Bibliographic record
Abstract
Abstract Particle‐induced x‐ray emission (PIXE) is an elemental analysis technique that employs a mega‐electron‐volt energy beam of charged particles from a small electrostatic accelerator to induce characteristic x‐ray emission from the inner shells of atoms in the specimen. The accelerator can be single ended or tandem. Most PIXE work is done with 2‐ to 4‐MeV proton beams containing currents of a few nanoamperes within a beam whose diameter is typically a few millimeters; a small amount of work with deuteron and helium beams has been reported, and use of heavier ion beams has been explored. The emitted x rays are nearly always detected in the energy‐dispersive mode using a Si(Li) spectrometer. Although wavelength‐dispersive x‐ray spectrometry would provide superior energy resolution, its low geometric efficiency is a significant disadvantage for PIXE, in which potential specimen damage by heating limits the beam current and therefore the emitted x‐ray intensity. In the proton microprobe, magnetic or electrostatic quadrupole lenses are employed to focus the beam to micrometer spot size; this makes it possible to perform micro‐PIXE analysis of very small features and, also, by sweeping this microbeam along a preselected line or over an area of the specimen, to determine element distributions in one or two dimensions in a fully quantitative manner. Most proton microprobes realize a beam spot size smaller than a few micrometers at a beam current of at least 0.1 nA. In trace element analysis or imaging by micro‐PIXE, the high efficiency of a Si(Li) detector, placed as close to the specimen as possible, is again mandatory for x‐ray collection. To date, PIXE and micro‐PIXE have most often been used to conduct trace element analysis in specimens whose major element composition is already known or has been measured by other means, such as electron microprobe analysis. However, both variants are capable of providing major element analysis for elements of atomic number down to .
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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 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".