Designing a High-Performance Quarter Waveplate for Improved Signal Quality in X-ray Magnetic Circular Dichroism Studies at EMA Beamline
Bibliographic record
Abstract
Abstract X-ray Magnetic Circular Dichroism (XMCD) is a key technique for probing the magnetic properties of intricate materials, utilizing differences in absorption spectra of circularly polarized X-rays with opposite helicities from a magnetized sample. At the EMA beamline in Sirius, polarization control is achieved through quarter-wave plates, enabling changes in X-ray helicity at a rate of 10 Hz. This work proposes an instrumentation redesign to increase the frequency of X-ray polarization switching, optimizing the use of EMA’s high photon flux and improving XMCD signal quality. The new design aims to oscillate crystals up to 200 Hz, operate between 3 and 22 keV, follow the high dynamic double crystal monochromator fly-scan at 1 keV / s, accommodate six different crystal configurations, and maintain a vacuum level better than 10−8 mbar. This advance is expected to significantly enhance XMCD studies, particularly for samples with very low magnetization, and advance research within the synchrotron community by providing a versatile and high-performance tool for investigating magnetic properties.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".