X ray production - doubts in the principle involved

[logearav]

X ray production -- doubts in the principle involved

Homework Statement

In x ray production, air molecules are ionised due to presence of very high electric field within the tube and positive ions are attracted to the cathode C and due to their impact electrons are emitted from the cathode.
I have a doubt in this. What is the underlying principle in which positive ions on collision with cathode, electrons coming out of cathode.

Homework Equations

The above scenario was before the advent of Coolidge tube.

The Attempt at a Solution

 

[1994Bhaskar]

When positive ions collide with cathode then they collide with atoms transferring energy.When this is greater then ionization energy then electrons are released.

 

[logearav]

I don't understand Bhaskar. Could u elaborate more, pls?