[ RadSafe ] Rb-87 Atomic Clocks

Mon Aug 1 10:59:21 CDT 2011

As I understand it (though this is not my field), the reason the
luminous paint fades is not that the paint actually wears off (which is
unlikely, as it hopefully is behind a bezel), but that more and more of
the "electron traps" fill, and the cascade that produces photons with
energy in the visible spectrum decreases.  The principle, as explained
to me, was much like the way that TLDs use crystals to store energy by
having electrons in a fairly stable energy above the ground state, with
that energy released as light when a little more is added (gross
oversimplification, I know).  In luminous paint, over time there are
fewer "places" where electrons can shift to that, when they drop back to
the ground state, release visible light.  I knocked around a couple of
ideas with someone who wanted to revitalize some radium dial from old
airplanes and such, an while there are some things that might work, such
as heating in an oven or using a laser to "anneal" the paint, neither of
us though experimenting in his kitchen would be a good idea.  

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of
franz.schoenhofer at chello.at
Sent: Friday, July 29, 2011 4:04 PM
To: The International Radiation Protection (Health Physics) MailingList;
Bernie Cohen
Subject: Re: [ RadSafe ] Rb-87 Atomic Clocks

RADSAFErs,

I am not at all knowledgable in those "atomic clocks", but I think that
the principle I can find out tomorrow on Wikipedia (it is past midnight
in Austria). The second question is for me, how the Rb-87 is produced,
it might have to be very pure or not? 

Personally I had and still posess an old wrist watch with radium dials,
most of them already lost their luminous paint, I have a wonderful old
alarm clock, whose ciphers do not glow any more, but show a considerable
activity. (BTW I received it from a previous US RADSAFE participant!)

I have done investigations on the diffusion of tritium from wrist
watches into the body, yielding very surprising results of relatively
high concentrations of tritium in the body. 

There is also a philosophical view of this question. I do not doubt at
all that for science and especially military applications very accurate
time determinations are an extremely must. But I doubt whether this
makes any sense for private use. 

There is a very great book available on "Universal History of Time" by
Hans Lenz, which deals with all aspects of the phenomen of time, from
philosophical concepts, astronomy, (lenght of days, months, years, moon
calenders, sun calenders, all their pitfalls etc), calenders,
measurement of time in many various cultural areas (Christians, Islam,
India, China, Indonesia, Japan, Middle and South America.....) and
measurement methods of time from old ages until the most modern methods.

.For all non-German speaking RADSAFErs a "caveat" - my copy is in German
and I rather doubt that it has been translated into English since its
publication in 2005. Those who are still interested in it are cordially
invited to contact me for closer information.

It is now 00:56 according to my wrist watch, 00:57 according both to my
computer clock and to my radiocontrolled weather station. My car usually
shows varying times, depending on how long the last adjustment has been
ago. Today it was about three minutes ahead, when I went with my mother
(87 years old) to Carnuntum, east of Vienna, which was a Roman
fortification and town almost 2000 years ago - how did they know when it
was time for dinner? (Sorry, this is  m y  way of joking.)

Best regards,

Franz

So much about watches and radioactivity for tonight
Best regards,

Franz

---- Maury <maurysis at peoplepc.com> schrieb:
> Hi Bernie,
> Here is one source, but they are costly ... I used a google search 
> including the quote enclosure: "Atomic Clock controlled directly by 
> internal Rb-87".
> Best,
> Maury&Dog {MaurySiskel maurysis at peoplepc.com]
> =============================================
> 
>
http://www.spectratime.com/ad/rubidium-oscillators/?gclid=COKNipT_pqoCFc
Q32godzX-aXw
> 
> ---------------------------------------------------------------
> On 7/29/2011 10:29 AM, Bernard L. Cohen wrote:
> > Where can you buy atomic clocks?
> >
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--
Franz Schoenhofer, PhD, MinRat
Habicherg. 31/7
A-1160 Vienna
Austria
mobile: ++43 699 1706 1227

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