Cryo-cooled sapphire oscillator operating above 35K

A mechanically compensated sapphire oscillator optimized for operation at 40 Kelvin

We present features for a second-generation thermomechanically compensated sapphire resonator. The new design shares the short thermal time constants characteristic of previously developed 10K and 77K CSO resonators. This, together with a thermal ballast methodology, allows effective compensation of temperature fluctuations over a wide range of time scales.