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

[Brian Kirby]

single page on the lamp only - is all I scanned

The whole document is available at NIST time group

Brian KD4FM

J. Forster wrote:
> 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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