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X-Rays in small microwave bulb?

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woodchuck

Mon Nov 14 2016, 12:12AM

Registered Member #39190 Joined: Sat Oct 26 2013, 09:15AM
Location: Boise National Forest
Posts: 65

johnf wrote ...
Glass stops x-rays up to 20keV.

The fluorescence that Kaye reports is described as occurring at the inside surface of the glass envelope, not throughout the thickness of the glass. No penetration of the glass is necessary.

Also, my first radiographs were produced via an Accel Supercoil connected to a dental tube - no multiplier or dual coils were required. I should post one or two of them here. Their quality was fairly good.

Finally, I would proffer one way to test the argon vs x-ray hypotheses: Provide what is called an 'alternate' gap. It would function as a crude voltmeter. If the alternate gap arcs only when the electrodes are close to each other, it's probably ionized argon glowing in the tube. If the electrodes can be moved apart by more than a cm w/o stopping all sparking, it's probably x-rays causing the fluorescence.

Polonium210

Mon Nov 14 2016, 02:46AM

Registered Member #3450 Joined: Sun Nov 28 2010, 05:01AM
Location:
Posts: 61

My assumption was that argon would fluoresce blue.

It is hard to tell from the pic I posted but the green is projected onto the inside of the glass in a pattern.
It looks to be streams of electrons coming from the sharp filament holder wires to the glass in a spot type pattern like an electron gun?

My HV source is as Woodchuck mentioned, an Accel Supercoil powered from 120v mains through a lighting dimmer and 1uf cap.

Physikfan

Mon Nov 14 2016, 10:46PM

Registered Member #60240 Joined: Mon May 16 2016, 07:01PM
Location:
Posts: 304

The color and the spectrum of an argon discharge tube are here:

Argon

thanks to physics stack exchange

http://physics.stackexchange.com/questions/79212/which-green-spectral-lines-are-emitted-in-a-thomson-tube

There are two possibilities:

Are the colors in your argon filled microwave bulb due to

a) a fluorescence of the glass hitted by electrons or
b) you can find some of the argon lines, shown above,
it may probably really only an argon discharge.

You can check it with a simple spectroscope.

If you can see a broad green band in the spectrum which may caused by fluorescence from the glass hitted by electrons it is a)

If you can find some of the argon lines, it may probably really only an argon discharge, it is b)

Mads Barnkob

Tue Nov 15 2016, 08:25AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

It is a very bright green/yellowish compared to the argon glow I have gotten in light bulbs before.

Here is my example of green colours from HV AC discharges in a light bulb:

Ash Small

Tue Nov 15 2016, 11:53PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Soft xrays can be produced under 5kv.they are considered soft until around 20kv.I believe the maximum permitted voltage for a CRT TV was 36kv.

Industrial and medical xrays generally start around 50-60kv, but are usually 110-120kv, as far as I'm aware.

Soft xrays are still dangerous, not a lot of penetration, but still cause skin cancer, etc.

hen918

Wed Nov 16 2016, 01:43PM

Registered Member #11591 Joined: Wed Mar 20 2013, 08:20PM
Location: UK
Posts: 556

Ash Small wrote ...

Soft xrays can be produced under 5kv.they are considered soft until around 20kv.I believe the maximum permitted voltage for a CRT TV was 36kv.

Industrial and medical xrays generally start around 50-60kv, but are usually 110-120kv, as far as I'm aware.

Soft xrays are still dangerous, not a lot of penetration, but still cause skin cancer, etc.

Soft x-rays should be the most dangerous if there is nothing to stop them, as all of their energy is absorbed into the body. Hard x-rays pass straight through, and cause little damage. I suppose x-rays between the two are the most dangerous, as they would penetrate deeply and still expend all of their energy on living tissue.

Physikfan

Thu Nov 17 2016, 04:52PM

Registered Member #60240 Joined: Mon May 16 2016, 07:01PM
Location:
Posts: 304

Hi all

This picture shows the luminescence of minerals in a GeiÃŸler tube caused by cathode rays, high voltage source is an induction coil.

MineralG1400x345

The yellow-green fluorescence of the glass gives an indication of the existence of low-energy x-rays,
very similar color compared to the microwave bulb under discussion.

Ash Small

Fri Nov 18 2016, 01:11AM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

You should be using lead shielding and not directly exposing yourself, your neighbours, and their cat to radiation.

Sulaiman

Fri Nov 18 2016, 11:01AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

Really !
you expect 10's kV x-rays to penetrate walls

johnf

Fri Nov 18 2016, 06:42PM

Registered Member #230 Joined: Tue Feb 21 2006, 08:01PM
Location: Gracefield lower Hutt
Posts: 284

And you do not need lead.
ordinary iron / stainless steel stops x-rays up to 60kV.
Which deterctor does your ludlum have you have not specified this yet??

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