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arXiv · 2505.24854

Practical primary thermometry via alkali-metal-vapour Doppler broadening

Nicola Agnew·Veronika Vohníková·Erling Riis·Graham Machin·Aidan S. Arnold
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Abstract

Doppler-broadening thermometry (DBT) can be used as a calibration-free primary reference suitable for practical applications, e.g. reliably measuring temperatures over long periods of time in environments where sensor retrieval is impractical. We report on our proof-of-concept investigations into DBT with alkali metal vapour cells, with a particular focus on both absorption and frequency accuracy during scans. We reach sub-kelvin temperature accuracy, and experimental absorption fit residuals below $0.05\,\%$, in a simple setup. The outlook for portable, practical devices is bright, with clear prospects for future improvement.

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Nicola Agnew, Veronika Vohníková, Erling Riis, Graham Machin, Aidan S. Arnold. 2025-05-30. Practical primary thermometry via alkali-metal-vapour Doppler broadening. https://doi.org/10.1098/rsta.2024.0455

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