[time-nuts] homebrew H maser

Magnus Danielson magnus at rubidium.dyndns.org
Sun Aug 29 14:13:21 UTC 2010

On 08/29/2010 03:55 PM, Attila Kinali wrote:
> Moin,
> I had a little bit too much time at hand this weekend and read a bit
> about H masers. I was quite astonished to see how "simple" these devices
> actually are. The electronics are basically a simple matter these days
> (thanks to the abundance of GHz devices for cell phones and GPS receivers).
> The only problem would be to build a high Q cavity, get a Teflon coated
> quarz bulb of the right diameter, an apropriate atomic hydrogen beam source
> and putting everything under high vacuum. Piece of cake ;-)
> Thus i wondered whether anyone had ever build a H maser outside
> national labs and and specialized companies. Looking at the time-nuts
> archives, quite a few people asked about the feasibilty of such
> an endeavor. A few times i read of people who actually attempted to build
> one, but never was there any website or any other resource with their
> results meantioned. Neither did big-g return any results when searching
> for these homebrew H masers.
> Does anyone know whether any of those people collected their results
> somewhere? And if, where i could find them?

The physical package is definitely where most of the effort goes in. A 
complicating aspect is the self-tuning stuff for which several 
strategies may be chosen.

You need to balance the rate of the atoms, as both too few and too many 
kills the oscillation.

The size of the glass-bulb is not a fixed thing, during research and 
development different sizes glass-bulbs is used to establish the 
wall-shift aspects in order to adjust for it, which is needed in order 
to make absolute measurements on the "free" atom resonance or compensate 
into that regard.

As for reference, there is about one set of books and papers from a 
handful of journals and a bunch of patents which needs to the read in 
order to build up the knowledge-base for attempting something like it.

It's a complicated field and several traps to fall into on the way. It 
is a fairly sizeable project to attempt.


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