High precision time-to-amplitude converter for diffuse optical tomography applications
Bibliographic record
Abstract
Molecular imaging aims to better understand biochemical processes at the molecular level in living organisms. Among emerging imaging modalities, diffuse optical tomography (DOT) coupled with the use of fluorescent bio-markers proposes solutions to visualize such processes. The Universite de Sherbrooke is developing a 128-channel DOT scanner dedicated to small animal imaging. The scanner is based on ultra-fast time-resolved optical measurements using time-correlated single photon counting (TCSPC). This paper reports a preliminary design of a high resolution 4- channel time to amplitude converter (TAC) used for time of flight optical measurements, in CMOS 0.18 mum technology. The TAC achieves a 5 ps resolution in a 13 ns timing window, and has a 150 ns dead time. It includes all auxiliary electronics: D-flip-flop, current source, integrator, switches and fully balanced buffer able to drive an off-the-shelf free running 50 Msps analog to digital converter (ADC).
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.010 | 0.003 |
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".