Development of ultrafast laser-plasma X-ray sources for time-resolved absorption studies in the 4-5 keV energy range
Bibliographic record
Abstract
Summary form only given. We present the progress in the optimization of laser produced plasma sources, specifically aimed the 4-5 keV X-ray energy range, using Ti and Ta wire and plane targets. Two table-top Chirped Pulse Amplification (CPA) laser systems were used: the INRS CPA laser (Nd:glass second harmonic @532 nm, 400 fs, 400 mJ, high pulse/pedestal contrast ratio, low repetition rate), and the UCSD CPA laser (Ti:sapphire @800 nm, 30 fs, 100 mJ 20 Hz repetition rate). The spectra of the emitted radiation were analyzed by the combination of a curved Si crystal spectrometer and an X-ray CCD camera arrangement. The PX-1 X-ray streak camera of INRS has also been used to follow the time history of multi-keV X-ray emission with subpicosecond temporal resolution. Comparison of the data collected with the two systems (INRS vs. UCSD) suggests the important role of the pre-pulse in achieving the maximum yield in a particular emission wavelength range. The pulse duration of the excitation pulses also has a strong effect in controlling the hot electron production processes in the rapidly expanding solid density plasma. Preliminary experiments on static absorption spectra of iodine at the L-III edge gave important data (photon statistics, signal-to-noise ratio) for designing future time-resolved EXAFS experiments based on laser produced X-ray sources.
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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 | 0.000 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".