Results on the DELPHI microvertex alignment from a precise 3-D mapping

Abstract The DELPHI microvertex has been carefully aligned for the 1990 period of data-taking at LEP e + e − collider using a multistep procedure. The first two steps are presented. Method and results of a precise mapping of the microvertex before the insertion in the DELPHI apparatus using a 3-D measurement machine are described in detail. Secondly procedure and results of an alignment algorithm using the interaction tracks are presented.