Acquiring an electron emitting mechanism for the double slit experiment with electrons I want to do the double slit experiment with electrons, and for that I need an electron emitting mechanism. I've been researching this topic on the internet, and I've come across electron guns that can't be bought, and things called electron vacuums that look weird.
Can you help me get an electron emitting mechanism? For example, by providing a website link or by typing the mechanism name.
 A: The vacuum requirement can be relaxed (to require only a high instead of ultra-high vacuum) if you use higher electron energies on the order of keV. The disadvtange is that you need very small "slits" to diffract with that high energy. You want large diffraction angles because otherwise your lackluster optics will ruin the outcome. That is why atomic lattices of crystalline surfaces are good starting points for electron diffraction. Of all the electron diffraction techniques, the RHEED is probably the easiest for hobbyist use.
For RHEED, you need:

*

*a vacuum chamber with better than ~1e-5 mbar vacuum. Can be still sealed using o-rings.

*a turbopump and prepump

*a phosphorous screen, can be salvaged from old CRT, e.g. oscilloscope. The vacuum chamber should have a window or be all glass, so you can see the screen

*the electron gun, which is best bought as a integrated part, aim for electron energies of at least a few keV. Alternatively, also salvage from old CRT, but I am not sure if the beam quality is good enough; maybe with a small hole in a plate for collimation.

*power supply for the electron gun. could be also salvaged from a CRT

*a crystal. As surface oxide will ruin the diffraction for silicon crystals, best look for oxides. An Al2O3 crystal might be the simplest thing to obtain and will be pretty inert.

The specular reflection in RHEED will be much much brighter than the diffraction effects. So typically you aim the specular reflection away from the screen, onto a dummy plate and only capture the diffracted potion of the outgoing electrons on screen.
