Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: Radiation cooling of grid
Date: Oct 18, 10:22 pm
Poster: Richard Hull

On Oct 18, 10:22 pm, Richard Hull wrote:

Interesting result, indeed. I have some grist for your mill. I am working a 1 inch diameter grid in
fusor III and find that at 25KV and 10ma the sucker is frighteningly bright and electron runaway often occurs in this range at pressures I currently work at.

That's about 250 watts, but I would note that the thing is running on the edge, but stable at 25kv, 8 ma (200watts) That would make the system grid about 1.25cm in radius and capable of about 110 watts or so by your calcs.

I think the electron emission runaway is the limiting factor on power for a grid. This in turn is a function of grid temperature and material chosen. Your result is more in line with simple SS grids in my experience. Tantalum and Tungsten can hit higher temps and survive. Also emmision should start at a higher temperature (more power in) in such systems.

Richard Hull