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arXiv · 2210.05545

Reliability and Reproducibility of the Cryogenic Sapphire Oscillator Technology

Christophe Fluhr·Benoît Dubois·Guillaume Le Tetu·Valerie Soumann·Julien Paris·Enrico Rubiola·Vincent Giordano
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Abstract

The cryogenic sapphire oscillator (CSO) is a highly specialized machine, which delivers a reference signal exhibiting the lowest frequency fluctuations. For the best units, the Allan deviation (ADEV) is <1e-15 for integration time between 1 and 10,000 s, with a drift <1e-14 in one day.The oscillator is based on a sapphire monocrystal resonating at 10 GHz in a whispering-gallery mode, cooled at 6 K for highest Q-factor and zero thermal coefficient. We report on the progress accomplished implementing eleven CSOs in about 10 years since the first sample delivered to the ESA station in Argentina. Short-term stability is improved by a factor of 3-10, depending on the integration time, and the refrigerator's electric power is reduced to 3 kW. Frequency stability and overall performances are reproducible, with unattended operation between scheduled maintenance every two years. The CSO is suitable to scientific applications requiring extreme frequency stability with reliable long-term operation. For example, the flywheel for primary frequency standards, the ground segment of GNSS, astrometry, VLBI, and radio astronomy stations.

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Christophe Fluhr, Benoît Dubois, Guillaume Le Tetu, Valerie Soumann, Julien Paris, Enrico Rubiola, Vincent Giordano. 2022-10-11. Reliability and Reproducibility of the Cryogenic Sapphire Oscillator Technology. https://arxiv.org/abs/2210.05545

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