[LEAPSECS] QB213 .R4 2013

[Tom Van Baak]

Rob,
Glad you got a chance to read that volume. I thought Steve and I were the only ones who spent time reading the history of atomic timescales over the last century. It's really quite fascinating, if you have the time.


> “Dr. STOYKO commented that even though the atomic standard is not a clock,

> it can still be used as a time-keeper through the intermediary of quartz clocks.”  […]


Please understand Stoyko's comment. In the early days the cesium beam apparatus was a frequency discriminator and could not, or was not, run continuously. The local time-scale was instead maintained by laboratory-grade quartz oscillator(s) and these drove the clock.

Once in a while, they fired up the cesium beam as a way to measure the absolute frequency offset and drift rate of the quartz oscillator. In the mid to late 1950's this necessity of re-calibration promoted the (valid) argument that atomic frequency standards were not "clocks".

However, by the end of the 50's, and certainly by the early 60's, commercial cesium clocks were available in quantity and were run continuously. You will see references to National Company's Atomichron as early as 1956,57,58.

At this point not only did atomic frequency standards get promoted to rightfully being called clocks, but multiple atomic clocks ran in multiple locations with time transfer by radio. With a critical mass of coordinated atomic clocks in place, there was no turning back. Atomic clocks were so much better than the planet, pendulum, and quartz clocks they replaced.


> The “atomic standard is not a clock”.


This was true for molecular and atomic frequency standards before about 1958.

Steve,
Thanks for the ADS links.

/tvb