Traceable state-matched radiometric calibration for gated line-scan spectroscopy at 100 kHz

Conventional radiometric calibration assumes stable illumination and an invariant system response, whereas microsecond-gated weak-light spectroscopy is highly sensitive to synchronized gating and readout. We present a traceable state-matched framework that treats the assembled optical path and synchronized acquisition state as the calibration object. A certified integrating sphere anchors the 1-kHz response, while frozen source-level, gate-width, and gain transfers are validated on held-out states. At 100 kHz, the system operated with a nominal 10 μs row interval and a programmed 1 μs electrical gate setting. Because the high-speed response was 22.96% lower than at 1 kHz, qualified scalar direct anchors were established at 550 and 600 nm. Held-out errors ranged from --1.56  to +0.40 formula units, and direct-anchor expanded uncertainties were 5.28% and 5.15% (k = 2). Plasma measurements demonstrate calibration-linked apparent spectral radiance retrieval from weak, nonrepeatable transient events.