[time-nuts] Can anyone spare an LPRO lamp?

[J. Forster]

I only see a page of descriptive text. Was there more?

-John

====================


> I have attached a low res scan of Robert J. Carpenter's paper NBS
> Technical Note 235, issued April 6, 1964.  Its a rubidium standard that
> was made for NBS.  Its the technical specs on the lamp.  I'm sure they
> probably do it a little different now, but it should give an idea about
> what went into the lamp.
>
> Brian - KD4FM
>
>
>
> Bob Camp wrote:
>> Hi
>>
>> The exact "fill" in the lamp is one of those things the Efratom does not
>> like to talk about. Best guess is that there is more than just Rb in
>> there.
>>
>> Bob
>>
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>> Behalf Of Neville Michie
>> Sent: Tuesday, September 29, 2009 12:19 AM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] Can anyone spare an LPRO lamp?
>>
>>
>> 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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