Tests Before Production

It is very important to make checks of the overall normalization of the experiment before proceeding with the production pass. Extracting absolute cross sections is a very good global check that the data make sense. Which reactions are chosen depend on the experiment. For electron scattering on hydrogen, we use the reactions ep elastic, ep $\rightarrow$ en$\pi^+$ and ep $\rightarrow$ ep$\pi^\circ$. For photon scattering on hydrogen $\gamma$ p$\rightarrow$ n$\pi^+$ and $\gamma$ p$\rightarrow$p$\pi^\circ$can be used. For polarized target running, the asymmetry on the proton is a useful check.