[time-nuts] Used Hydrogen Maser, and Mercury Stored-Ion Clocks

[Demetrios Matsakis]

For what it’s worth, the mercury ion clocks were shipped to the US Naval Observatory.  HP shortly thereafter did a market survey and concluded there was not enough profit in it.   They did allow Len and Robin to give short-answer support, and the project fell to me.   I found the clocks were not performing well due to sudden vacuum-contamination events.   Len, Robin, and I published our data in the proceedings of the 1995 Frequency Control Symposium.  At about the same time, JPL came up with a second generation design.   They kept improving it, and 20 years later this is now the Deep Space Atomic Clock, which was just launched.  See https://www.nasa.gov/mission_pages/tdm/clock/index.html <https://www.nasa.gov/mission_pages/tdm/clock/index.html>  and https://en.wikipedia.org/wiki/Deep_Space_Atomic_Clock <https://en.wikipedia.org/wiki/Deep_Space_Atomic_Clock>

As for costs for an unit that is not space-qualified, I would guess you still need a lab with PhD’s and skilled technicians because I doubt much of the hardware is commercially available.

Demetrios Matsakis, as of this Saturday a USNO retiree, and as of August 1 a consultant for Masterclock.

> FWIW, about 20 years ago, Len Cutler and Robin Giffard of 5071A fame
> built several Hg ion clocks to be shipped to some govt customer I
> don't remember.  One of the clocks was dropped by the shipping company
> UPS or FedEX) and destroyed.  Only then did Len learn that HP was
> self insured, probably as part of a package deal to get a low
> corporate shipping rate.  HP products were packed extremely well, so
> the only real risk was the unit getting stolen.  I vaguely remember
> Len saying they were out $10K, which was probably just the cost of
> parts.  Nevertheless, it didn't seem like building an Hg clock was
> all that big of a project.  Way simpler than the 5071A.
> Now a days, the electronics would be considerably easier and cheaper. 
> The mechanical parts would all be CNC'ed by an online machine shop.
> 
> Rick N6RK
>