RE: Thorated vs Pure Tungsten

Hi BIll, all,

> Original Poster: wysock-at-ttr-dot-com 
> To Terry (specifically) and All,
> Please reconsider your design for a "safety gap."  I worte to you
> before, about using either brass or copper sphere electrodes,
> for this purpose.  They can either be solid machined pieces, or
> hollow-spun units.  The solid pieces are needed where you are
> operating at a.c. input levels above about 5 Kva.  The "ball gap"
> offers a very well defined E-field stress line model, between the
> two electrodes, assuming that they are polished and very smooth
> and of a constant radius of curvature.

A useful and simple substitute for a ball gap (which I also like) is 
to use two pieces of pipe set at right angles to each other. It's 
bulkier and perhaps more hassle to mount but approximates a spherical 
gap rather well for a very low cost. The pipe ends need to be well 
insulated to avoid corona leakage.