[time-nuts] Home built cesium clocks???

Magnus Danielson magnus at rubidium.dyndns.org
Sat Jun 28 11:14:28 EDT 2008

From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
Subject: Re: [time-nuts] Home built cesium clocks???
Date: Sun, 29 Jun 2008 01:52:36 +1200
Message-ID: <48664224.5070004 at xtra.co.nz>

> swingbyte wrote:
> > G'day fellow time-nuts.
> >
> > I was just going through some old projects and found my old home-made 
> > mass spectrometer.  This was a project based on a design from either 
> > Scientific American or The Amateur Scientist back in the '60s.  I was 
> > wondering if anyone here had heard of a similar project for a cesium 
> > clock?  Although my home built mass-spec wasn't in the same league as a 
> > bought one, it did work and did get me a HD in physics!  How hard is it 
> > to make a cesium clock?  Just thinking about it and wondering what is 
> > actually inside the physics package.
> >
> >
> > Tim.
> >
> >   
> Not a great deal:
> A Caesium oven
> A mechanical collimator for the Caesium beam
> A pair of state selection magnets
> A Caesium detector
> A pair of Microwave cavities

The microwave cavities should have a phase-stable distribution inbetween them
and also a stable physical distance.

Getter to capture stray atoms.

C coil.

The physical package should be magnetically shielded.

Also, an ion pump.

A variation would optically pump the cesium beam rather than using the original
state selection magnets. I have not heard of any commercial cesiums using that
technique, it is only used in a few lab cesiums.

Masspectrometers seems to be the most popular detection method too, but
optical detection is again used in a few lab cesiums.

The physical package is along with the RF chain the most problematic parts.
The rest is no big magic, but needs to be done with care.


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