RF banding effects in vacuum tubes (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 03 Oct 2003 19:24:01 +0000
From: Mike Novak <solschoice@xxxxxxxxxxx>
To: hvlist@xxxxxxxxxx
Subject: RF banding effects in vacuum tubes

Hi all,
I'm new to the list, so please don't burn me if there's a similar thread in
action already.
Anywho, I was wondering if anyone knew of a source of info on the "string of
pearls", "dotting", or "banding" effect caused by high voltage RF in vacuums
at moderate pressures.
If there is no research out there I was thinking of doing some experiments
with this.
In my own experience, I've seen this phenomena only two times. One was in
neon signs, at work and in other businesses. In the signs you can see bands
or dots develop during pumpdown or in old signs. In old signs, the dots
sometimes move around a bit, but hold a constant spacing and size. However,
during pumpdown, they appear more as bands and change spacing with pressure.
In my own experiments with vacuum discharges, I've seen this effect during
pumpdown between 10 and 1 Torr, roughly. and in my larger diameter tube, I
notice that the bands are more like hemispheres - most likely a result of
wave propagation. No doubt there is some sort of resonance condition
involved here.
If I could determine what causes the spacing, size and contrast of the high
energy regions, one could do some interesting experiments. I was thinking of
using an array of electrodes to create an interference region in which each
transmitting electrode would contribute a small amount of energy to creating
a saturated energy cavity; one with no "zero" crossing or time to cool down.
Maybe that could find use in a neutron generator or something.
Comments?

-Mike

_________________________________________________________________
Instant message with integrated webcam using MSN Messenger 6.0. Try it now
FREE!  http://msnmessenger-download.com