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CRTs emit gamma ray at high power(>5kV is usually the quoted figure), and the standard solution was a bandaid fix of attaching leaded gamma ray blocking glass o
by numpad0 12d ago
CRTs emit gamma ray at high power(>5kV is usually the quoted figure), and the standard solution was a bandaid fix of attaching leaded gamma ray blocking glass onto the screen. This high lead glass cannot be recycled, and the EU(rightfully) don't like any of that. I don't know if manufacturing of CRTs are banned or legally infeasible, but it's clearly not encouraged.
There are still some types of CRT-related vacuum tubes in production for applications digital equivalents are objectively less performant in.
- agalunar 12d agoX-rays! not gamma rays.
- duskwuff 12d ago> There are still some types of CRT-related vacuum tubes in production for applications digital equivalents are objectively less performant in. Like what? The only significant applications I'm aware of for vacuum tubes nowadays are high-power RF amplifiers (including household microwave magnetrons) and intentional X-ray emitters.
- numpad0 12d agoNight vision goggles. The photodiode + CsO + lead coated charged glass capillary amp thing is apparently still superior to solid state image sensors with amplifiers in metrics like SNR, minimum luminosity, and longer wave IR response. The performance gap is wide enough that there's a Chinese Norinco subsidiary that entered the market during 2010s by licensing technology from an EU company.
- protocolture 12d agoYou can get these tiny 3 inch black and white CRTs from china. They arent really good for anything but writing hackaday articles tho.
- mrob 12d agoLeaded glass was a cost-cutting measure, used only for the back and sides of CRT. Leaded glass gradually turns brown under X-ray exposure, so the front screen used barium and strontium instead. There's no reason the whole CRT couldn't use this kind of glass. There are probably other heavy elements that would work too. (Early black-and-white CRTs running at lower voltage did use leaded glass for the front too, but they aren't the CRTs people interested in old games care about.)