[time-nuts] More HP5065 experiments

[Attila Kinali]

On Mon, 28 Sep 2015 22:59:27 +0200
Magnus Danielson <magnus at rubidium.dyndns.org> wrote:

> > There should be somewhere a mention how much the frequency shift
> > of an Rb vapor cell due to light intensity change is, but i couldn't
> > find a good number in a couple of minutes. If you need one, please let
> > me know and I look a bit more carefull.
> 
> You really should check J. Vanier and C. Audoin "The Quantum Physics of 
> Atomic Frequency Standards, Volume 2" Chapter 7 Rubidium Frequency 
> Standards.

Oh.. right. I totally forgot about that book!

> Now, it is interesting to note that the temperature of the filter cell, 
> the temperature of the lamp cell and the intensity of lamp plasma 
> interacts here. For a optimum filter cell temperature, you can cancel 
> the lamp intensity.

Yes. There is a myriad of processes that shift the frequency.
I sometimes wonder how they are able to build primary standards
at all. Yes, modern techniques like using lasers get rid of a couple
of the processes, but still there are many that change the measurement
ever so slightly.

> Anyway, those plots give strong indication that measuring the light 
> intensity from the detector and then servo the intensity can be a good 
> strategy.

If possible, I'd also check the spectrum of the lamp before and after
the filter, depending on different lamp voltages, temperatures and
filter temperatures. But that depends on having an optical spectrometer.

PHK: if you want, you can borrow one of mine Ocean Optics HR2000.
 
> W.J. Riley "Rubidium Frequency Standard Primer" is a good read, but 
> Vanier&Audoin is much more fundamental.

Oh.. I didn't know about Riley's book. Thanks for the hint.

BTW: for those who are looking for Vanier&Audoin, don't try to get
a print version. They are unobtanium. And even if you find one, they
are horribly expensive. CRC offers the pdf's for 750USD, which is
waaaay overpriced for what they did (quite a cheap scan of the books,
without even doing OCR). The pdf's are floating around on some websites
though.

Alternatively you can buy the updated version by Vanier and Tomescu which
has been released last month. But I cannot say anything about its content
as I haven't had the time to buy it, yet.

Also an alternative is Fritz Riehle's "Frequency Standards: Basics and
Applications". Eventhough this has been also out of print, the pdf's
have a more reasonable priced (150EUR), or are available using your
favorite university library for "free"
( http://onlinelibrary.wiley.com/book/10.1002/3527605991 ).
Riehle mentioned a couple of years ago that he is planing to update
and republish his book, but apparently this has not happend yet.

				Attila Kinali

-- 
Reading can seriously damage your ignorance.
		-- unknown