Luminosity calibration

The experiments do not only require high collision rates and integrated luminosity, but also an absolute normalization of the observed cross sections. This normalization can be derived from theoretical predictions or the determination of the absolute luminosity. During the 2010 proton run, the Van Der Meer scan method was used to provide a first measurement of the absolute luminosity from machine parameters. Based on the outcome of the Lumi Days workshop, future requirements, prospects and alternative methods (vertex, high-β) will be summarized. Implications on machine operation and protection will be discussed.