Rubidium fountains actually launch ions up against gravity so that they are in free fall (in a vacuum, with magnetic fields nulled out) during their sample period. That's not something I can see being miniaturized, or put in use on a moving platform.
Atomic fountains use neutral atoms. It is almost impossible to see the effect of gravity on ions since a single stray electron anywhere in your system creates a way larger Coulomb force.
Fountains need to have a minimum size in order to achieve a sufficient flight time when throwing the atoms up on a ballistic trajectory. Obviously, they also have to be very carefully aligned with respect to gravity.
Comments
Is it Caesium?
I thought Rubidium fountains were easier to minaturise. I can't see where I can find out how the device is made - there's not much detail.
Ah - you're right, it's Caesium. https://ww1.microchip.com/downloads/en/DeviceDoc/A3405FE2-C1...
I used to run an NTP server, in the pool. But it was stratum 2; it would stroke my ego to run a stratum 1 server. But 3.5 kilodollars: I'll wait.
Rubidium fountains actually launch ions up against gravity so that they are in free fall (in a vacuum, with magnetic fields nulled out) during their sample period. That's not something I can see being miniaturized, or put in use on a moving platform.
Atomic fountains use neutral atoms. It is almost impossible to see the effect of gravity on ions since a single stray electron anywhere in your system creates a way larger Coulomb force.
Fountains need to have a minimum size in order to achieve a sufficient flight time when throwing the atoms up on a ballistic trajectory. Obviously, they also have to be very carefully aligned with respect to gravity.