A Low-Power Photon-Counter Front-End Dedicated to NIRS Brain Imaging
Bibliographic record
Abstract
This paper introduces a new miniaturized on-chip photodetector front-end targeted for portable near infrared spectroscopy as a noninvasive tool for real-time brain imaging. It includes silicon avalanche photodiodes (SiAPDs) with dual detection modes using a transimpedance amplifier (TIA) with on-chip gain/bias control, and a controllable mixed (active-passive) quench circuit, with tunable hold-off time, and a novel gated quench-reset technique. This integrated photoreceiver front-end has been fabricated using submicrometer standard CMOS technologies with a minimum fill-factor of 95%. Fabricated SiAPDs exhibit avalanche gains of 35 and 22 at 10 and 18 V bias voltages with red-shifted peak photon-detection efficiency and dark count-rates of 114 and 4 kHz (at 1 V excess bias voltage). The TIA consumes 1-mW power, and offers a transimpedance gain of 250 MV/A, a tunable bandwidth (1 kHz-1 GHz), and an input current referred noise <;10 fA/√Hz at 1 kHz. The photon-counter exhibits a quench-time of 10 ns with a 0.4-mW power-consumption with an adaptive hold-off time control. The on-chip integration of SiAPDs and front-end circuit, reduced the power-consumption and after-pulsing, and increased the sensitivity.
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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 | 0.000 |
| 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 | 0.001 |
| 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".