Richard,

This has been an entertaining monologue on electron tubes. (Must be
International Fractured Physics Week on RRAA.)

I won't attempt to address the numerous howlers, since Henry seemed
satisfied with your tale, but you might want to rethink the item you
"correct" in this message.

Secondary electron emission also occurs at much lower incident electron
energies. As a metrologist you are most likely familiar with electron
microscopy. Secondary electron emission is the typical mode of detector
operation. The incident electron energy in modern SEM's is now in the
range of 500 to 700 volts.

One of the reasons for adding more grids in vacuum tubes is to manage
secondary emission from the plate. This occurs at much less than 17 kV.

73,
Gene
W4SZ



Richard Clark wrote:
On Tue, 07 Jun 2005 11:44:29 -0700, Richard Clark
wrote:


When that electron stream strikes the plate and raises the
temperature, it is just short enough power to present this secondary
emission. But if we were to run at 17KV or so, then the electron
stream would be so aggressive as to produce high energy effects such
as X-Ray emission.


Something felt wrong here. I should have said:
...just short enough energy to present this secondary emission.

On Tue, 07 Jun 2005 20:17:28 GMT, Gene Fuller
wrote:

One of the reasons for adding more grids in vacuum tubes is to manage
secondary emission from the plate. This occurs at much less than 17 kV.

Hi Gene,

Sure, but not X-Rays which attend Cold Cathode tubes (skipping the gas
filled tubes I've already touched upon) and do require elevated
potentials to be so useful (that they become dangerously useful).

Glad you won't attempt the other howlers.

73's
Richard Clark, KB7QHC