[time-nuts] One Kg Quartz Resonator

Bob Camp lists at rtty.us
Tue Jan 22 15:01:47 EST 2013


Hi

The objective of the Avogadro Project seems to be getting to an accuracy of
0.03 ppm from a current level of ~ 10X that. The suggestion in the paper is
that a quartz resonator could be monitored for change to a much tighter
level than that.

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Bruce Griffiths
Sent: Tuesday, January 22, 2013 2:39 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] One Kg Quartz Resonator

Poul-Henning Kamp wrote:
> Content-Type: text/plain; charset=ISO-8859-1
> --------
> In message<7CC93B1ACC5743A3B5536DBF798B7016 at vectron.com>, "Bob Camp"
writes:
>
>    
>> There's a paper in the February IEEE UFFC transactions proposing that the
SI
>> standard of mass be replaced with a 1 KG quartz resonator.
>>      
> Has anybody ever studied if mono-isotopic quartz in the first place ?
>
> I pressume that would be a requirement in order to link it to the
> atomic weight unit ?
>
>
>    
The current intention is to accurately measure Silicon 28 single crystal 
spheres and use the result to refine the value for Avogadros number and 
thus allow a redefinition of the kilogram using Avogadros number and the 
mass of an atom:

http://www.ptb.de/en/aktuelles/archiv/presseinfos/pi2011/pitext/pi110127.htm
l

Essentially one would then measure mass of such standards by counting atoms.

Bruce
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