[time-nuts] Re: Mitigation of lamp oven and cavity oven temperature-induced frequency variation in rubidium atomic clock

[Attila Kinali]

On Tue, 21 Feb 2023 21:21:25 +0100
Attila Kinali <attila at kinali.ch> wrote:

> Not only is light intensity one of the factors that shift
> frequency, the intensity that hits the sensor is modulated by two
> independent processes with different causes that have different
> frequency shift characteristics.

Sorry, small correction here, as this is not quite right.
There are quite a few more processes that change the amount
of light hitting the sensor:

* RF power of the lamp
* RF frequency of the lamp
* Lamp temperature
* Lamp bulp absorption of rubidium into the glass
* Vapor cell temperature (i.e. vapor pressure)
* Vapor cell absorption of rubidium into the glass
* RF power of the vapor cell
* RF frequency of the vapor cell

to name a few....

Some of these are usually adjusted/kept constant in modern
devices. Others are not or cannot be measured/compensated.

To make a Rb vapor cell standard stable, these influences have
to be accounted for independently as they have different
effect magnitudes on the resulting frequency shift. Mushing
them all into a single measurement values forgoes a lot of
potential for additional stability at best. At worst it makes
the system less stable.

			Attila Kinali
-- 
The driving force behind research is the question: "Why?"
There are things we don't understand and things we always 
wonder about. And that's why we do research.
		-- Kobayashi Makoto