A Monster Encounters Quarks

A great idea (klystrons) leads to electron linear accelerators all the way to the 3 km long ‘monster.’ They are first used to determine the size of nuclei and then to look deep inside protons, where partons were discovered that were later identified as the quarks. Quantum chromodynamics emerges as a theory for the strong nuclear force that even explains why quarks are quasi-free inside protons, but can never escape individually.