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: Grid loss not losses
Date: Jul 12, 09:01 am
Poster: Richard Hull

On Jul 12, 09:01 am, Richard Hull wrote:


Hector pointed ot something in the final post of a recent thread. That is, that the central grid is slowly but surely eaten alive by bombardment. This is sort of unavoidable due to the type device we are using which is a variant of a deposition system.

I recently had to disassemble fusor III and "miked" the grid wires. The original .030 tantalum wire was down to .026 or so after a number of hours of operation (estimated about 40). Most of my run time is in glow cleaning mode and preparation for use by ion pumping as well.

Some of you folks out there might not be aware of this fact. At some point your grid gets too thin due to this and its dissapative power falls and its emissive properties increase. Remember, an orange to white hot glowing inner grid is an electron emitter at a point where we really can't use them. (Ions created close to the inner grid and not getting full acceleration.) Be prepared to make another central grid at some point if you operate your system near full power for long periods.

Cooling schemes or ideas for keeping the inner grid from becoming too emissive is a good effort where the amateur might contribute.

Richard Hull