[time-nuts] homebrew H maser
Richard W. Solomon
w1ksz at earthlink.net
Thu Sep 2 14:21:33 UTC 2010
This discussion reminds me of a time long ago when I
worked at a University. We had one rather obnoxious
Grad Student, who, although brilliant, was a Royal PITA.
So, while constructing his vacuum system, and getting
hassled by him, I located one of the Universities residents,
a large water bug. Which I let loose in the vacuum plumbing.
He was beside himself for about a week, wondering why he
could not get pumped down to the level he expected.
73, Dick, W1KSZ
-----Original Message-----
>From: jimlux <jimlux at earthlink.net>
>Sent: Sep 2, 2010 6:29 AM
>To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
>Subject: Re: [time-nuts] homebrew H maser
>
>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
>few torr).
>
>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 ...)
>
>_______________________________________________
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.
More information about the Time-nuts_lists.febo.com
mailing list