[time-nuts] homebrew H maser

[J. Forster]

>
> 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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