Nice description. I didn't know atomic clocks just sampled Cesium atoms for a second at a time every once in a while -- I always thought they were somehow continuously amplifying that oscillation. So in reality, they are just recalibrating a more traditional circuit at regular intervals, which serves as the clock for some digital circuit?
For anyone with even a passing interest in frequency standards, I recommend watching this recent seminar by Bill Phillips on recent changes to the SI. Bill provides some interesting history on atomic clocks, context on why Cs was chosen, and perspective on the remaining problems with the definition of the second.
It seems like a challenge to tune anything to the exact resonant frequency of the caesium, since it's an attempt to find a maximum output. My first thought was to take multiple measurements at different frequencies and curve fit the response to get a maximum. But then you'd have to somehow compensate for differences among sources and maybe detectors.
Hill climbing to the top is challenging.
Cesium fountains are such a crazy idea that sound like they're some fevered sci-fi concept.
Does the gravity force affect measurement? Iām curious if there is a tidal effect that can be observed from the various locations of the Moon and Sun.
Would there be merit to putting a cesium fountain in zero g? Or would relativistic wobble neutralise the benefit of longer observation periods?
This might be common knowledge, but it was a recent TIL for me. Chip scale atomic clock:
https://www.microsemi.com/product-directory/clocks-frequency...
10^-11 short-term stability; about 10^-9/month drift