Angular X-ray transmission measurements of gold absorption gratings: comparison of different laboratory X-ray sources
Bibliographic record
Abstract
Over the past few years, numerous advances have been made in X-ray imaging technology. X-ray imaging plays an important role in the non-destructive exploration of the internal structures of objects for research, medical and industrial applications. When X-rays are used in computed tomography (CT), the differences in density of various components of a specimen result in different degrees of absorption of the X-rays and are ultimately responsible for image formation and image contrast. However, in some situations, this contrast is not sufficient for the sample, e.g. in the case of fossils embedded in rock, there are often situations where the fossil and rock have similar grey values. Poor contrast causes the loss of valuable detail and makes further image processing steps such as segmentation challenging. There is a continuous need to improve and develop new image acquisition techniques with the goal to improve the quality of the obtained CT data. Computed tomography techniques have been extended to phase contrast imaging in recent years using the principle of Talbot-Lau interferometers. Initially performed in synchrotron facilities the method was extended to work with incoherent polychromatic X-ray sources by introducing a source grating into the setup and therefore reducing the requirements on the spatial coherence of the source significantly. In this work, we report on the experimental characterization of gold absorption gratings used in such a laboratory-based cone-beam phase contrast setup. The gold gratings are characterized by Angular X-ray Transmission using different laboratory X-ray sources, providing insights not only into the grating feature sizes but also validating the suitability of the available laboratory source for phase contrast imaging. This work is the first step in a project implementing phase contrast X-ray imaging in laboratory setups in South Africa.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| 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".