How do you obtain electrons and know their average velocity?

[quantumfoam]

How do you obtain electrons and know their average velocity??

Hello guys! I am currently trying to experiment with charge accelerators. I soon tripped inside a really big hole. I soon realized that I didn't know how to measure the amount of charge(in coulombs) a charged conductor has. So instead of using charged objects, I decided to use electrons. How would I go about obtaining electrons? Most importantly, how could I measure the average velocity of a beam of the electrons I obtained (if I am able to obtain them).

 

[mfb]

I am quite sure that there is a deeper problem in the whole setup...
To get the electron velocity, you can shoot them into a magnetic or electric field and measure the curvature/deflection. Alternatively, keep track of the accelerating voltage, and calculate the velocity based on that.

 

[quantumfoam]

Hi guys! Yes, I thought about that last night. I decided to use a velocity selector and a hot cathode electron emitter with a low work function. The velocity selector will only allow the electrons with the desired velocity pass through the magnetic and electric fields. Provided that I apply enough energy to the hot cathode. Thanks!