Luminosity optimization

Once circulating beams have been established residual transverse offsets remain at the interaction points which can be the source of a significant luminosity reduction. Using the Van der Meer scan method, where one beam is swept stepwise across the other while measuring the collision rate as a function of beam displacement, these offsets can be minimized in order to optimize the luminosity. This method was successfully used during the 2009 LHC run at the four interaction points. The first experience, measurements and problems encountered will be presented as well as possible improvements for the upcoming run.