[time-nuts] Can anyone spare an LPRO lamp?
Neville Michie
namichie at gmail.com
Tue Sep 29 04:19:16 UTC 2009
The lamp in the LPRO may have a significant difference from the other
lamps.
The pictures of lamps on Tom's ? page show that each of them has a
side arm
which is most helpful for filling.
The side arm is left out in the cold so any excess rubidium condenses
there
as a reserve supply. The vapour (vapor) pressure of rubidium is then
determined
by the temperature of the side arm.
The LPRO does not seem to have a side arm, at least I did not see one
when
I looked at mine, and if it has it does not seem to protrude out of
the oven.
I can not guess how they filled it. Remember it is mainly empty, I
think, although
it may have an inert gas in it besides the rubidium vapour. With
the right amount
of rubidium in the tube the pressure will always be right, the only
problem is that
alkali vapours are infamous for diffusing into warm glass, and with
no backup supply
of rubidium the vapour pressure will drop and the fire will go out.
Can anyone tell me what the lamp looks like? Mine seems to be a
simple glass
sphere.
cheers, Neville Michie
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