Here's a fun story.
I was at a "typical" 2010s-era birthday party with liquid nitrogen, microscope crystals, UV paint, weird DIY internet foods, etc. Me, I supplied the uranium glass, GM counter, vac pump+chamber, argon and high voltage.
:)
While my alpha-window GM counter was chirping away on the coffee table, suddenly its output went crazy. Roaring, needle-pinning!
It's WW-III!
Nope. It's 1920 quack medicine. Someone was running their Renu-Life violet wand teslacoil device about 8ft away from the counter. But that doesn't make sense. Quack-medical devices put out a bit of UV only. Well, sometimes their RF hash can get picked up by a poorly-shielded probe cable.
But no, the culprit was one particular attachment. It was a significant source of soft, easily-shielded x-rays. Aha, that particular glass "violet-ray electrode" doesn't glow purple like all the rest. Instead, it's dark inside, but with brief flashes of green fluorescence on the glass. With the violet wand output being upwards of 50 to 75KV, that might also be the peak KEV of any x-ray photons. Maybe not so "soft." Also, unlike all the other glass electrodes, this one had a coiled wire stretched along the tube, inside the vacuum. The better to capacitively couple the HV terminal to the vacuum- insulated glass?
I looked it up, and there it was: 1919 catalog, Renu-Life electrode no. 27, "patented, Tonic Satuator, impossible to receive a shock."
Apparently when you hold thirty kilovolt electrodes against your body, you can get zapped in the legs (from your metal chair.) This low-picofarads vacuum electrode attempted to fix that problem, but in the meantime produced fifty KeV x-rays. Good for testing GM counters, without needing to buy any Torbernite ore samples from rock shops on eBay.
PS
It's known that vacuum-filled light bulbs can produce some x-rays when connected to a Tesla Coil output. Modern bulbs with argon/N2 fill will just glow, and cannot support the needed kilovolts. And, their x-ray output usually isn't enough to visibly light a fluorescent screen. But it certainly makes your alpha-window GM counter freak out.
PPS
Here's the very first violet wand, 1905, $4000 in modern USD:
Hmm, the Electrotherapy Museum is no more? All his files gone offline? Someone should offer to host it, long term! Only seven GB, he says.
((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))) William J. Beaty