Homemade CRT

This is a quick video demonstrating a simple CRT I made out of some parts laying around the lab. The phosphor layer was a little thick so the spot from the electron beam wasn't visible from the other side.

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Also I am getting back into the swing of things (somewhat) and have much more time to make videos, so stay tuned!

[mikeshilale]

Careful. That thing's probably emitting x-rays.

[videosuperhighway]

Nice i need a 32 inch crt. Can you build one to replace the old tube on my admiral.

[jrbpyro]

@jmm078 It was Zinc Sulfide and I obtained some 10 micron powder (doesn't necessarily need to be this thin, this is just what I had at hand) and mixed it up in some alcohol to make a slurry. Then I poured a little into the bottom of the vial and used a heat gun to slowly evaporate the alcohol off. If you do this, make sure you don't heat it up rapidly otherwise your powder layer will almost 'explode' off and it sprays everywhere and your left with an unusable layer of Zing Sulfide.

[timedude]

The reason there is no spot on the phosphor is because this is NOT a CRT it is simply a low pressure gas discharge tube, to make it a crt the cathode must be made of a metal with a low work function, and it must be heated to emit cathode rays, also the electrons must form a coherent beam, this is done by focusing electrodes, and the anode must not pick up all of the electrons, for a CRT to work, you must accelerate the electrons and have them go past the anode and strike the phosphor. oh, and the thicker the phos. layer the higher energy the electrons must carry to illuminate it. Beta Radiation is high energy electrons.

[oak_meadow]

separate the anode from the cathode, Break open an old tube and retrive the gun material, its electrons are more losely bound than Al foil. Good job for a prototype, need an accelleration screen to brighten

[jrbpyro]

No, I did actually check it with an x-ray sensitive geiger counter and it never read over background. I was only using a few thousand volts, so if x-rays were being generated, they were most likely being stopped by the glass.

[BitGridTV]

0:54 more powerr Igorr!!!

sry, couldnt resist :D

no, this looks very good and inspirational

[exoplanet]

Neat. Thanks. More details on the construction of the electron emitter would be appreciated.

Also is that blue glow Cerenkov light?

I'm curious how easy it would be to take the electron gun out of a CRT and use it to produce electrons & show the deflection.

[SebisRandomTech]

This is very cool. Wonder if you can get it to a point where it can display images?

[BillyMicon]

lol, geiger counter reacts on xray and glass stops xray... this is really amaizing:D

[lamboroghini]

can you please make a video about how to make the electron gun(?) part? and do you still have any quicksilver that you want to get rid of?

[jmm]

Great work. What was the phosphor you used, and how did you deposit it? Thanks!

[Jeffrey]

Have you made homemade "peanut" tubes (subminiature valves) like those that came out in the very early 1920's to cash in on the radio craze that had started after WW1?
A jury-rigged technology that used existing miniature electric lamp bulbs of the time

[jrbpyro]

@jmm078 This goes for when your trying to heat a heavy suspension of a compound, when you rapidly evaporate the liquid off it almost super dries the powder left behind and make it crack and pop and ruin your surface.

[jrbpyro]

@nodariel Thanks for the comment! You are correct. In normal vacuum settings you wouldn't typically see this, but the reason for the gas in this system is the high out-gas rate of the plastic and phosphor inside the tube.

[robertgift]

Nice!
Use a metal pen tube as your cathode cover so electrons flow through the small opening.
Cold cathode? (No heated filament)

[jrbpyro]

I have 4 diff pumps, but this type of CRT, because of its crudeness, doesn't deserve a diffusion pump on it. Maybe down the road when I make something a little higher quality.

[JPa]

I love the bluish colored electron beam! What type of class jar was that?

[Commack]

was that bluish glow visible to the naked eye or only to the camera.. And what exactly is that? Is it a visible electron stream ? Amazing stuff..

[seepoowoop]

You can get phostphor from a florucent tube if anybody does not know