Practical primary thermometry via alkali-metal-vapour Doppler broadening

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Agnew, Nicola and Vohníkova, Veronika and Riis, Erling and Machin, Graham and Arnold, Aidan S. (2026) Practical primary thermometry via alkali-metal-vapour Doppler broadening. Philosophical Transactions of the Royal Society A: Mathematical Physical and Engineering Sciences, 384 (2312). 20240455. ISSN 1471-2962 (https://doi.org/10.1098/rsta.2024.0455)

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Abstract

Doppler-broadening thermometry (DBT) can be used as a calibration-free primary thermometer suitable for practical applications, e.g. reliably measuring temperatures over long periods of time in environments where sensor retrieval for recalibration 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 set-up. The outlook for portable, practical devices is bright, with clear prospects for future improvement. This article is part of the Theo Murphy meeting issue ‘The redefined kelvin: progress and prospects’.

ORCID iDs

Agnew, Nicola, Vohníkova, Veronika, Riis, Erling ORCID logoORCID: https://orcid.org/0000-0002-3225-5302, Machin, Graham and Arnold, Aidan S. ORCID logoORCID: https://orcid.org/0000-0001-7084-6958;
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