- Rb vapor standards have very low acceleration effects. As Dave
said, the control loop will kill most of the effects inside the
loop frequency. The loop frequency is relatively fast, in the
order of couple of 100Hz to a couple of 10kHz, depending on the
exact build of the Rb standard and what type of crystal they used.
Contrary to what he says, there are no acceleration dependent
diffusion effects. The vapor cell is is heated and the gas atoms
in there are pretty fast, any acceleration of them will be negligible
compared to what they do upon collision. The relativistic red shift due
to acceleration is way too low to measure (much lower than the intrinsic
noise). The only mechanical effect that is possible, is bending of
the microwave cavity or the parts inside. But given that the cavity
is several mm thick aluminium and everything is mounted rigidly,
I very much doubt that there is any significant effect.
Correction: I just had a look at the LPRFS specs. It lists a 2g tip-over
sensitivity of 2*10^-10/g on the worst axis. I have no idea what's going
on there. No other of the Rb vapor standards of which I have the spec
at hand list any acceleration sensitivity.
Attila Kinali
--
It is upon moral qualities that a society is ultimately founded. All
the prosperity and technological sophistication in the world is of no
use without that foundation.
-- Miss Matheson, The Diamond Age, Neil Stephenson
On Mon, 17 Oct 2016 16:44:55 +0200
Attila Kinali <attila@kinali.ch> wrote:
> 3) Rb vapor standards have very low acceleration effects. As Dave
> said, the control loop will kill most of the effects inside the
> loop frequency. The loop frequency is relatively fast, in the
> order of couple of 100Hz to a couple of 10kHz, depending on the
> exact build of the Rb standard and what type of crystal they used.
> Contrary to what he says, there are no acceleration dependent
> diffusion effects. The vapor cell is is heated and the gas atoms
> in there are pretty fast, any acceleration of them will be negligible
> compared to what they do upon collision. The relativistic red shift due
> to acceleration is way too low to measure (much lower than the intrinsic
> noise). The only mechanical effect that is possible, is bending of
> the microwave cavity or the parts inside. But given that the cavity
> is several mm thick aluminium and everything is mounted rigidly,
> I very much doubt that there is any significant effect.
Correction: I just had a look at the LPRFS specs. It lists a 2g tip-over
sensitivity of 2*10^-10/g on the worst axis. I have no idea what's going
on there. No other of the Rb vapor standards of which I have the spec
at hand list any acceleration sensitivity.
Attila Kinali
--
It is upon moral qualities that a society is ultimately founded. All
the prosperity and technological sophistication in the world is of no
use without that foundation.
-- Miss Matheson, The Diamond Age, Neil Stephenson
