Crookes fluorescent and phosphorecent minerals tube

[jeffddow]

im gonna build an induction coil and i was curious, are you making xrays with those vacuum tubes?

[AlastairWright]

@jeffddow

Some Crookes tubes produce X-rays, but if you see a blue gas glow from inside the tube you can be fairly sure there's no X-rays. If you see green glass fluorescence and no gas glow then better beware!

[robertgift]

Is UV (Ultraviolet) light produced by the gasses in the glass envelope causing the samples to fluoresce?

A test for that would be to have a hinged barrier shade the samples from cathode and anode.

If still glowing, it is from UV generated uniformly in the gas.

[AlastairWright]

@robertgift

The minerals glow from bombardment by electrons otherwise known as 'cathode rays'. At low vacuum there is no plasma glow and no UV produced. Old cathode ray tube televisions and monitors work by exactly the same principle.

There are Geissler tubes which produce UV light and some of these have powder that fluoresces under UV. That's the origin of fluorescent and neon lighting.

[robertgift]

@AlastairWright Thank you. Since the gas in the tube IS glowing, could there not be UV emitted from it. Or does that require some Hg vapor?

Would be nice to see what happens in a hard vacuum.

Yes, there may be some internal gases slowly released by the samples. But in a hard vacuum, we would see NO corona at the electrodes and no glow in the glass envelope.

[AlastairWright]

Take a look at the windmill tube video.

No gas discharge and the windmill glows because it's painted with powdered minerals.

[giakful]

I would love to have this object. where can I buy it?

[sean6006]

That's how L.E.Ds were discovered!

[438426x1]

lol thats probably producing X-Rays

[whitefalcon113]

Quite a few i would imagine. lulz

[erjohnson227]

It is actually quite unlikely. There would need to be a sufficiently concentrated beam of electrons striking a mineral which produced the x-ray region radiation when energized. all that these are producing is the visible spectrum. I wouldn't be surprised if there were some radiation however. Just not enough to make a difference.

[Dri0m]

@438426x1 dangerous x-rays is above 15kV

[Lokivoid]

But anyways thanks for posting this, Makes me wanna get back into collecting old coils and violet rays (oudin coils). Btw where did you obtain that large induction spark coil?

[OLTCITKA]

Great videos! Thanks a lot for them! Everyone of your videos is very awesome! :D

[CrashByron]

I heard these things give of soft X-rays.

[douro20]

Yes, but at very low levels.

[Lokivoid]

About the same amount as any other CRT (includeing monitors and TV's) The amount it gives off is allmost nothing and is perfectly safe. Do not confuse a vacume tube with a X-ray tube wile they both work on the same concept the X-ray tube is designed to focus,amplify and redirect the xray. What you see here is basicly a Low atomsphere of a inert gas usely neon or argon and a excitable Phsphorecent material, In short a flourescent bulb. Its prefectly safe, Well outside of the high current

[tesla242]

Amazing stuff  like you always present!