Pulsed quantum cascade laser based cavity ring-down and cavity enhanced spectroscopy for the detection of ethylene.
Bibliographic record
Abstract
We investigated the use of a pulsed, distributed feedback (DFB) quantum cascade (QC) laser centered at 970 cm<sup>-1</sup> in combination with cavity ring-down spectroscopy (CRDS) and cavity enhanced spectroscopic (CES) techniques for the detection of ethylene. In these techniques, the laser is coupled to a high-finesse cavity formed by high reflectivity mirrors. In the CRDS application, the laser frequency was tuned at a rate of ~0.071 cm<sup>-1</sup>/K by changing the heat sink temperature in the range between -20 and 50°C. For off-axis CES, the laser was excited with short current pulses (5-10 ns), and the pulse amplitude was modulated with an external current ramp which gave a frequency scan of ~0.3 cm<sup>-1</sup>. We utilized a demodulation approach followed by numerical filtering to improve the signal-to-noise ratio. Basic instrument performance and optimizations of the experimental parameters for sensitivity improvement are discussed. We demonstrated a detection limit of ~130 ppb with CRDS and ~15 ppb with off-axis CES for ethylene.
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How this classification was reachedexpand
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".