[time-nuts] time-nuts Digest, Vol 101, Issue 152

Jim Lux jimlux at earthlink.net
Mon Dec 31 17:15:23 UTC 2012

On 12/31/12 8:13 AM, Magnus Danielson wrote:
> On 31/12/12 16:56, Bob Camp wrote:
>> Hi
>> I suspect that your ion standard will have some issues from magnetic
>> field. Quartz it's self has no magnetic sensitivity. Most atomic
>> gizmos have sensitivity as part of their basic physics.
> All atomic clocks that I know of have this sensitivity.
> One strategy is to look at the side-band features and steer the C-field
> accordingly. The dynamic range needed after my-metal shield(s) might be
> something to consider. Helmholtz coils might be applied, as it has been
> in early stages of research.

I'm sure they're thinking of all this..

Typically, the requirements set for something like this are the union 
(and superset) of all previous devices which they supersede (USOs in 
this case), so they'd probably want the magnetic field influence to be 
less than it is for USOs.

The Hg-ion trap isn't so much the challenge as getting it all built and 
packaged in a space qualifiable way. And meeting the 1 kg/1 liter target 
mass/volume.  It's taken a few years to get from "physics package 
demonstrated as prototype on benchtop" to "physics package manufactured 
as a product with full drawings, processes and decent yield" and I 
believe the current work for the past couple years is more on getting 
all the supporting electronics (electro optics, RF, HV power) also in a 
form that is manufacturable and qualifiable.

We all joke that getting your widget working on the bench is about 10% 
of the cost/time/work to getting it ready for space flight, but it's not 
that much of a joke.

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