Famulus fusion
new shots with new langmuir probe and electron gun commence!
Prometheus starts new shots with new langmuir probe and new electron gun
http://prometheusfusionperfection.com/
some probs with higher than desirable pressure it seems
read all about it
http://prometheusfusionperfection.com/
some probs with higher than desirable pressure it seems
read all about it
ah, I think I may have imparted the wrong meaning there slightly. To quote Mark Suppes directly:Tom Ligon wrote:Higher than desirable pressure in a Polywell ... sounds like he's got it working normally.
If you can keep it sealed and pumped down, they do tend to "clean up" somewhat with time, but pressure rise is chronic and my biggest worry for the practicality of this approach.
so it seems its actually problem with his converted CRT/electron gun lacking some intensity, thus 'requiring' higher pressure for plasma. something he's trying to work on now.Famulus wrote: ...
But when I tested the {NEW} electron gun I saw a problem: It needs 25 millitorr of air to strike a plasma, up from the 8.5 millitorr of the original configuration. This is a problem because high pressure reduces potential well formation.
...
wish i could help, but i know not how.
Electron Guns
I'm actually working with two different electron guns.
The first gun is based on the original Sydney experiment. It looks like this:
https://picasaweb.google.com/lh/photo/T ... directlink
This gun requires a low pressure gas to operate.
The second gun is based on a CRT. Looks like this:
https://picasaweb.google.com/1026021299 ... 6476180802
The CRT gun runs in a total vacuum because the electron are generated from a hot cathode. I have yet to get this working in the vacuum chamber.
The advantage of the CRT based gun is much lower operating pressure.
The first gun is based on the original Sydney experiment. It looks like this:
https://picasaweb.google.com/lh/photo/T ... directlink
This gun requires a low pressure gas to operate.
The second gun is based on a CRT. Looks like this:
https://picasaweb.google.com/1026021299 ... 6476180802
The CRT gun runs in a total vacuum because the electron are generated from a hot cathode. I have yet to get this working in the vacuum chamber.
The advantage of the CRT based gun is much lower operating pressure.
Re: Electron Guns
many thanks for the clarification famulu - all is now much clearer.FAMULUS wrote:I'm actually working with two different electron guns.
The first gun is based on the original Sydney experiment. It looks like this:
https://picasaweb.google.com/lh/photo/T ... directlink
This gun requires a low pressure gas to operate.
The second gun is based on a CRT. Looks like this:
https://picasaweb.google.com/1026021299 ... 6476180802
The CRT gun runs in a total vacuum because the electron are generated from a hot cathode. I have yet to get this working in the vacuum chamber.
The advantage of the CRT based gun is much lower operating pressure.
good luck with the gun
I would expect a CRT e-gun to be a bit low in emission current to run a Polywell, but very good for some diagnostic applications.
We were known to use headlight filaments as emitters in some of the early work. For higher emission they can be doped with strontium or barium salts or carbonates, if you don't mind handling toxic materials.
A small e-gun bombarding another surface might be useful. Supposedly diamond films, graphene, and buckytubes can be stimulated to emit electrons copiously.
We were known to use headlight filaments as emitters in some of the early work. For higher emission they can be doped with strontium or barium salts or carbonates, if you don't mind handling toxic materials.
A small e-gun bombarding another surface might be useful. Supposedly diamond films, graphene, and buckytubes can be stimulated to emit electrons copiously.
i'm supposing some posh, off the shelf, gun would be nice if there was the budget - something with decent focusing, columnating/deflction controls, etc all build-in, calibrated an ready to go.
i'm sure i found a couple of manufacturers of precision lab gear on the web a while ago, mislaid the links - all pretty expensive stuff as i recall.
also some guns for beam-lithography - which i fancied might be 'somewhat' over-kill - i'm not sure what the optimal spec would be for this kind of experiment. any ideas?
i'm sure i found a couple of manufacturers of precision lab gear on the web a while ago, mislaid the links - all pretty expensive stuff as i recall.
also some guns for beam-lithography - which i fancied might be 'somewhat' over-kill - i'm not sure what the optimal spec would be for this kind of experiment. any ideas?
My expertise on electron-emitting diamond films, etc, is limited to reading a few blurbs in sources such as Science News. The article on diamond films cited a particular firm doing research on them. When I contacted them they seemed almost alarmed that the information was out, and totally clammed up. Another Navy project, I guess. (Sigh.)
http://www.mendeley.com/research/electr ... thin-film/
http://www.sciencedirect.com/science/ar ... 3297801481
http://www.google.com/patents/about/569 ... ofAAAAEBAJ
The discoverer of graphene won a Nobel just recently. Graphene might be easier than diamond film or buckytubes.
http://www.ncbi.nlm.nih.gov/pubmed/21850356
Plain old graphite can supposedly be coaxed into emission if bombarded with ions. Graphite also enhances carbon nanotube emissions ... likely because single-atom-thickness flakes are essentially graphene.
http://www.google.com/patents/about/653 ... ENAAAAEBAJ
We used "dispenser cathodes" for a while, which are high-current emitters intended for industrial applications and lasers. These proved tempermental. Kept at very low pressures they work great, but they poison easily and they inactivate if bombarded with ions due to high pressure exposure.
RWB never thought focussed guns were all that important, but it may be worth looking up the term "extractor grid." Child-Langmuir law (a special case of Poisson's equation) stipulates the current limitation of an emitter due to space charge, and that turns out to be worst case at the emitter surface (slow electrons causing a traffic jam). Applying a potential of a few hundred volts close to the emitter surface typically improves emission significantly. Once emitted, the electrons should know where to go.
The place you need a tight electron beam is diagnostics ... they can be handy for density measurements in a vacuum, for example. However, the magnetic fields in a Polywell make that a challenge. Lasers or microwaves are more likely the practical density measurement tool.
http://www.mendeley.com/research/electr ... thin-film/
http://www.sciencedirect.com/science/ar ... 3297801481
http://www.google.com/patents/about/569 ... ofAAAAEBAJ
The discoverer of graphene won a Nobel just recently. Graphene might be easier than diamond film or buckytubes.
http://www.ncbi.nlm.nih.gov/pubmed/21850356
Plain old graphite can supposedly be coaxed into emission if bombarded with ions. Graphite also enhances carbon nanotube emissions ... likely because single-atom-thickness flakes are essentially graphene.
http://www.google.com/patents/about/653 ... ENAAAAEBAJ
We used "dispenser cathodes" for a while, which are high-current emitters intended for industrial applications and lasers. These proved tempermental. Kept at very low pressures they work great, but they poison easily and they inactivate if bombarded with ions due to high pressure exposure.
RWB never thought focussed guns were all that important, but it may be worth looking up the term "extractor grid." Child-Langmuir law (a special case of Poisson's equation) stipulates the current limitation of an emitter due to space charge, and that turns out to be worst case at the emitter surface (slow electrons causing a traffic jam). Applying a potential of a few hundred volts close to the emitter surface typically improves emission significantly. Once emitted, the electrons should know where to go.
The place you need a tight electron beam is diagnostics ... they can be handy for density measurements in a vacuum, for example. However, the magnetic fields in a Polywell make that a challenge. Lasers or microwaves are more likely the practical density measurement tool.