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

[Magnus Danielson]

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.

Cheers,
Magnus