SVD ladder mock-up assembly for the Belle II experiment

This paper describes an assembly procedure for a silicon vertex detector (SVD) ladder mock-up for the Belle II experiment at High Energy Accelerator Research Organization (KEK) in Japan. The Belle II experiment aims to test the standard model (SM) precisely and to search for new physics beyond the SM by studying rare B meson decays. The SVD is one of the main components in the Belle II detector and detects vertices and tracks of particles. The SVD has four layers, each of which consists of double-sided silicon strip detectors (DSSDs), readout chips with circuit boards, and ribs to support the ladders. The outmost layer called L6 is composed of five DSSDs. We fabricated mechanical and dummy samples to make the L6 ladder mock-up and connected the ladder to the end ring to complete the assembly procedure. Two assembly methods were used, and the position's precision after completion of the assembly was measured. The position's precisions in the x- and the y-directions were found to be less than 0.5 mm, which is the precision required for the SVDïs physics performance. The measurements showed that the position's precision depended on the assembly procedure.