A Novel Metrology Standard for Synchrotron Produced Monochromatic X-ray Beams
Bibliographic record
Abstract
Purpose: X-ray beams produced using synchrotrons have unique properties that are of interest to radiotherapy investigations and the characterization of radiation detectors.To facilitate the use of synchrotron produced photons in such investigations, this project aims to determine the absorbed dose to water at depth for synchrotronproduced monochromatic x-ray beams with a standard uncertainty less than 1 %, significantly lower than current methods.Methods: The absorbed dose to water at a depth of 2 cm, D w, 2cm , was evaluated using a purpose built novel aluminum calorimeter design.Finite element modeling and radiation transport simulations were performed to refine the design, calculate correction factors, and assess influence quantities.Two iterations of the design were constructed to test calorimeter operation and a comparison of the quantity air kerma, using a secondary microDiamond detector, was performed.Results: The combined standard uncertainty in the determination of absorbed dose to water was estimated to be 0.89 %, and was found to be constant for monochromatic energies investigated (80 keV to 140 keV).No dependence on calorimeter design was observed and the comparison with the microDiamond detector showed agreement in the determination of air kerma rate at the 1.5 % level, providing confidence in the new calorimeter standard.Conclusions: This new calorimeter has been shown to accurately determine absorbed dose to water in synchrotron-produced x-ray beams with a substantially lower uncertainty compared to current methods.Routine operation has also been demonstrated, providing a new high-accuracy dosimetric tool for users of synchrotron beams, initially in Canada but potentially at sites worldwide.
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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 | 0.004 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".