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numpad0today at 12:58 AM3 repliesview on HN

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.


Replies

mrobtoday at 1:59 PM

Leaded 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.)

agalunartoday at 2:53 AM

X-rays! not gamma rays.

duskwufftoday at 3:01 AM

> 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.

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