On 01/19/2011 06:44 PM, Poul-Henning Kamp wrote:
In message<[email protected]>, "Bob Camp" writes:
Conventional gas cells have a finite lifetime on the
lamp.
It used to be that Rb's would fail lock because the bulb dimmed from Rb
absorption into the glass, but I think they got that fixed with a teflon
coating.
Thes days most of them ultimately fail from the high operating temperature,
through a variety of mechanisms.
For the CSAC, my bet would be that the laser is the limiting factor.
I agree, for the CSAC I would expect that the laser would slowly dim,
especially as it sits within the oven. Not optimum to keep the junction
temperature down.
For my older Rubidium, the Rubidium lamp had splattered the Rubidium.
When I heated it the first time I did get a dimmed glass, but heating it
again orienting it properly (so hot gas rising into the back where I
wanted it) I resolved the problem... within minutes. So I really wonder
if it absorbs into the glass.
Exactly why splattered rubidium cause a problem for the rubidium lamp I
am not 100% sure about, but my guess is that maybe it will expose too
large area and thus causing too large gas-pressure to let the RF-field
light up the gas. If someone who actually know could explain it, I would
be happy to learn.
Cheers,
Magnus
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