Quark Matter-Attoscale Electron Microscopy of the Proton

We review experiments colliding electrons (/positrons) on protons at high energies at HERA, focusing on the ZEUS experiment. We describe the ZEUS detector, including its data acquisition system, and look at a specific part, namely the electronic system for its calorimeter readout control, in more detail. Data analysis is described, and results pertaining the proton structure is given. It is found that the naive quark model cannot explain the results obtained at small fractional momentum, and this requires quantum chromodynamics. Also it is found that diffractive reactions, with large rapidity gaps, contribute substantially; efforts are being carried out to understand them.