[time-nuts] homebrew H maser

[Paramithiotti, Luciano Paolo S]

I am rally interested to be part of a team of people with the target to built an active H Maser.
If there are in the world persons who are really interested in, it will be a good starting point.
To built specific parts there are several way to do it in ham saving mode, for example for the cavity I can find a friend of main that have high precision machine to phisically prepare it and so on. First of all is important to find the team.

Hope hear you,


Luciano P. S. Paramithiotti



-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of J. Forster
Sent: giovedì 2 settembre 2010 18.59
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] homebrew H maser

>
> jimlux at earthlink.net said:
>> The gas diffusing out through the drilled bolt.. sure it's drilled, 
>> but the conductance is so patheticaly low, you're literally waiting 
>> until  the gas molecules happen to randomly bounce their wey up the 
>> hole.
>
> I've never worked with vacuum gear.
>
> I assume "drilled bolt" refers to a bolt through a drilled hole so 
> there is some slop between the bolt and the hole.

No. It's used where a bolt goes into a blind hole. It is to vent the trapped gas more quickly to reduce "virtual leaks"

> Can I use vacuum grease as a seal around the bolt?  Or does it outgas 
> too much if you are going for seriously low pressures?

Basically no. SS bolts are lubed to prevent sieze up, but not in vacuum.

> Can I use a soft(er) metal washer and mash it to a gas tight fit by 
> tightening the bolt enough?

Conflat (and other) fittings use OHFC copper gaskets (one use only. Take it appart and you must use new ones). Also Indium and Gold are used.

> How low a pressure does a H maser need?   Where is it relative to say
> fingerprints outgassing?

The vacuum areas must be really clean. Think vapor degreasing with Trichlor.

> Is there an easy to understand scale of difficulty?  (like dishes 
> rattle for the Richter scale)

On a scale of 1 to 10:

1   getting a GPS DO working.
3   getting a Rb working from scratch.
9   getting a H2 MASER working scratch.
15+ getting an Ion trap working.

And, like the Richter, this is a log scale.

FWIW,

-John

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