[time-nuts] homebrew H maser
jimlux at earthlink.net
Thu Sep 2 13:29:01 UTC 2010
Poul-Henning Kamp wrote:
> In message <4C7F5918.7030101 at xtra.co.nz>, Bruce Griffiths writes:
>> Indicates that the operating pressure at the hydrogen dissociator is
>> likely to be a few Torr or so.
> The pressure is basically: "As low as possible" in order to minimize
> hydrogen collisions (other hydrogen, walls) as much as possible.
A few torr is actually not a particularly high vacuum (e.g. your run of
the mill neon sign is pumped down a lot lower before being filled to a
PHKs comment implies you're looking for mean free path somewhat greater
than physical dimensions...
That would imply pressures less than a micron (0.001 Torr).. MFP =
5E-3/P with P in Torr.. 1 micron pressure == 5cm MFP
The other thing is when you're looking at MFP comparable to dimensions,
you're looking at molecular pumping in some form (no more pistons or
rotary vanes or ...)
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