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.