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: Grid loss not losses (cooling)
Date: Jul 13, 12:38 pm
Poster: Jim Lux

On Jul 13, 12:38 pm, Jim Lux wrote:

>At Los Alomos National Labs, they have an IEC that uses an active coolant through the grid to keep it from having the problems mentioned below by Mr. Hull.
>>Cooling schemes or ideas for keeping the inner grid from becoming too emissive is a good effort where the amateur might contribute.
>>Richard Hull
>I once discussed this with some people and the only solution to simplifying the cooling of the grid was using conduction. If you attach the ..

I suppose that if you are cooling it actively, then there isn't the need for a refractory metal like tantalum to build the grid. What about using something like silver, which has high heat conductivity (or suitably doped conductive Diamond ) to connect to your cold finger. Or, just pass a suitable coolant through the actual grid elements, which could be something like hypodermic tubing.

A suitable coolant might be high pressure hydrogen gas.. low viscosity, high conductivity, low density, etc... It is used in many HV cooling applications like high speed turbogenerators. He might also be a good choice?

Any idea how much heat is actually being dissipated on the grid? Since it is in a vacuum, it doesn't take much to get it pretty hot, esp if it is made of something like stainless steel which has low thermal conductivity. That is, until it gets hot enough to glow and radiation losses become significant.