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As a mathematician, I have practically zero experience and knowledge of experimental methods. Recently, learning about some famous experiments in the history of quantum physics, I heard about an experiment in Japan (the names of the people involved has long since departed from my memory) that confirmed de Broglie's idea of 'matter waves', i.e. that wave-particle duality isn't just for photons.

The idea, as I remember, was that electrons were fired very slowly at a detector plate, but there was a small filament running perpendicular to the detector, so that it would block some electrons. As predicted, however, over time, the pattern on the detector showed interference patterns that we would normally expect from waves.

My question is not about the quantum physics behind this, so much as the actual experimental methods. How do you actually prepare a bunch of electrons in a specific state, and then how do you actually 'fire' them all, from the same point, one after the other? Is there some sort of molecule that you can prepare that chucks out electrons when you hit it with something else, or something like this?

More generally, I suppose, is there some sort of study/reference for experimental methods, or is it the sort of thing that you just learn as a physicist? For example, if I want to do an experiment but need to know how to make electrons, say, in a certain state, and fire them at a certain speed, and then prepare some photons in a certain state and do something with them, etc., would I turn to a certain book and look at the chapter 'How To Prepare And Fire Electrons At Various Speeds And In Certain Quantities', or would I look back at previous experiments, or would I just look at my notes from the lectures I followed during my under/post-graduate studies on experimental methods?

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Electrons have charge and thus their trajectory and speed can be manipulated by an electric field.

A standard procedure to make a beam of electrons would be to pass current through a conductor.
Eventually the conductor will get hot enough to the point where the electrons on the surface have enough energy to escape.
You can allign this disoriented "spray" of electrons by a controlled, external, electric field.

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