What is this magical material that image intensifier tubes use for the front?

[msalko]

Hi,
I'm trying to make my own image intensifier tube.
And i can't find anywhere what the front part that turns photons to electrons actually is.

I know that it has to do with a photo electric effect, but i doubt that it's a slab of tungsten as it has to be transparent.

Does anyone have any information on this?

Thanks in advance.

[msalko]

Ha! There's a website that actually lists materials that can be used as photocathodes (the front bit)

https://photocathodes.io/

there's some that are dirt cheap to make, like potasium chloride.
idk how good that's going to be but, i can test it out easily *dances*

[ikrase]

In general, these are centered on either alkali metals such as sodium or potassium, which of course must be applied by special methods and may be sensitive to air, or semiconductors such as GaAs. For effective image intensifiers, this is deep in the realm of ultra-purity and exotic stuff.