Control of X-ray hazard in femtosecond electron diffractometer
Bibliographic record
Abstract
In a femtosecond electron diffractometer (FED) electrons are generated by a 266 nm laser beam with 8 μJ/pulse by hitting a gold-coated quartz disc (photocathode). The electrons are accelerated in an electric field up to 300 keV. 1 mm thick Silicon disk with a 400 μm hole is used as anode and also for collimation of the electron beam. The electrons passing through the hole will hit the sample and create the diffraction pattern. Due to the high voltage, a considerable amount of X-rays are produced inside the vacuum chamber of the diffractometer. The steel walls and the glass windows do not offer enough shielding to reduce the dose rate around the instrument to acceptable levels. In this paper we will present the engineering and administrative controls put in place to control the X-ray hazard and to comply with the requirements of the Ontario Ministry of Labour.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".