Apparatus for high-resolution microwave spectroscopy in strong magnetic fields
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Bibliographic record
Abstract
We have developed a low-temperature, high-resolution microwave surface-impedance probe that uses cavity perturbation of dielectric resonators and is able to operate in high static magnetic field. This method has sufficient sensitivity to resolve the microwave absorption of submillimeter-sized superconducting samples. The resonators are constructed from high-permittivity single-crystal rutile (TiO2) and have quality factors in excess of 106. Resonators with such high performance have traditionally required the use of superconducting materials, making them incompatible with large magnetic fields and subject to problems associated with aging and power-dependent response. Rutile resonators avoid these problems while retaining comparable sensitivity to surface impedance. Our cylindrical rutile resonators have a hollow bore and are excited in TE01(n−δ) modes, providing homogeneous microwave fields at the center of the resonator where the sample is positioned. Using a sapphire hot-finger technique, measurements can be made at sample temperatures in the range of 1.1–200K, while the probe itself remains immersed in a liquid-helium bath at 4.2K. The novel apparatus described in this article is an extremely robust and versatile system for microwave spectroscopy, integrating several important features into a single system. These include operation at high magnetic fields, multiple measurement frequencies between 2.64 and 14.0GHz in a single resonator, excellent frequency stability, with typical drifts <1Hz∕h, the ability to withdraw the sample from the resonator for background calibration, and a small pot of liquid helium separated from the external bath that provides a sample base temperature of 1.1K. Without modification, this system can be employed for dielectric spectroscopy, electron-spin resonance, and other microwave spectroscopies.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.000 |
| 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 it