Design of a 30 um aperture membrane hydrophone for the measurement and characterization of High Frequency ultrasound
Bibliographic record
Abstract
The field of High Frequency micro-ultrasound (ultrasound having centre frequencies greater than 15 MHz) is growing, with clinical and pre-clinical array based systems having centre frequencies of up to 50 MHz currently in production. Limitations in hydrophone technology related to the size of hydrophone apertures, limited bandwidth, and limited calibration range are problematic for clinical regulatory measurements. A method of making a membrane hydrophone with an active area as small as 10 um, having very low field fringing effects is presented. A new method of creating well aligned electrodes on opposite sides of a very thin polymer membrane have been developed and successfully implemented using proprietary FujiFilm VisualSonics Inc. (VSI) Excimer laser technology. Measurements made using newly developed 30 micron membrane hydrophones, including custom electronics and amplifiers, are presented. Calibration results to 110 MHz are presented along with a discussion of uncertainties and challenges related to measuring acoustic fields in water at 50 MHz centre frequency and high pressures.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".