particle physics - How are the protons for collisions in the LHC made?

I heard that the LHC smashes two protons together to research the universe.

But how does it create the protons for collision? If we strip off the electrons won't there be neutrons along with protons?

A "Duoplasmatron source" is used by the LHC, it ionises atoms into negative or positive ions but how is the proton separated from that?