Fusor Anode 'Volume' Effect

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Dennis P Brown
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Fusor Anode 'Volume' Effect

Post by Dennis P Brown » Sat Nov 11, 2017 5:59 pm

Testing my fusor with an anode mesh screen to 'reduce' the active plasma volume did, in fact, affected my fusor's best operating pressure. My previous best pressure (no reduced anode volume) was 5 micron to 7. The voltage for that original system was 32 kV and between 25 to 30 ma (which yielded about 82 kilo-neutrons a second.)

With the mesh added my working pressure jumped to 14 microns; again, at 32 kV and 25 - 30 ma. Both systems were highly stable (once I cleaned my system - had been off-line for nearly a year! So, surprised it settled down after about fifteen minutes of operation (plasma burn in.))

What I was trying to achieve was create an equivalent anode volume to what a 2.7 inch diameter chamber would exhibit (same length), even though my chamber is considerably larger (and this was my original, no screen, 'anode' - i.e. my fusor chamber walls.) The mesh was a cylinder shape about 2.7 inches in diameter and had about the same length as my previous chamber's effective anode length. Essentially, the length was not changed between the two systems relative to what the cathode experienced.

Interesting that for essentially identical systems relative to vacuum volume (but not plasma volume; that was reduced a great deal), the working pressure was significantly different even through both fusor main chamber sizes/total volume are identical. All I did was install the mesh to create a smaller anode diameter (the mess instead of my chamber walls.) This simple addition doubles the amount of deuterium in my system but my total ionized deuterium apparently dropped (from 785 cc to just 230 cc. So while my deuterium quantity doubled in my chamber the my plasma volume decreased by almost 2/3. So my net ionized deuterium decreased by about 50%. A rather interesting experiment, none-the-less.

Unfortunately, my new attempt with a neutron detector gave no results so, that part of the experiment was a failure. So, I have no data on that effect. When I started trying to figure out the issues, I discovered a major issue with my voltage splinter (three way.) One of the coaxial connectors was design to isolate the attached cable - a very bad thing since this would cause noise issues to develop in my ST-360 (and these were occurring with everything off - the fusor, and the HV power supply for detector. That was really a serious over-sight.) Replaced that part but still having issues.

Thanks John - just got back and saw your correction - does not pay to rush writing a post ... what a mesh ... I mean mess,that resulted in ...lol.
Last edited by Dennis P Brown on Sat Nov 11, 2017 10:48 pm, edited 4 times in total.

John Futter
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Re: Fusor Anode 'Volume' Effect

Post by John Futter » Sat Nov 11, 2017 6:54 pm

Dennis
By Mess I think you mean Mesh

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