Smoothing the LHC During LS1

The two-yearLong Shut-Down 1 (LS1), triggered by the repair of the splices in the interconnections of the Large Hadron Collider (LHC) cryo-magnets, gave the opportunity to the survey and alignment team to smooth the position of the 27km of the LHC in order to guaranty its best performance for the RUN2 expected between 2015 and 2018. For the first time after the starting of the LHC, the roll angle of the LHC cryo-magnets as well as their position in vertical and in horizontal (transverse) were measured. This large measurements campaign has allowed a realignment of many components and will be an important source of information useful for the analysis of the stability of the LHC, allowing then the survey team to predict the areas where the future movements are going to take place.This paper gives an overview of the techniques and the software used for the smoothing, the realignment process and a preliminary analysis of the stability of the LHC.