Integration and Characterization of the Vertex Detector in SuperKEKB Commissioning Phase 2

Abstract

As an upgrade of asymmetric $e^+e^-$ collider KEKB, SuperKEKB aims to increase the peaking luminosity by a factor of 40 to $8\times 10^{35}$ cm$^{-2}$s$^{-1}$. The SuperKEKB commissioning is achieved in 3 phases. The Phase 1 was successfully finished in June 2016. Now the commissioning is working towards the Phase 2 targeting to reach the luminosity of $1\times 10^{34}$ cm$^{-2}$s$^{-1}$. In Phase 2, the beam induced background versus luminosity and beam current will be further investigated, to ensure a radiation safe operation environment for the Belle $\text {II}$ vertex detector during the Physics data taking in Phase 3. Closed to the beam pipe, 2 pixel and 4 double-sided strip detector layers will be installed, together with the dedicated radiation monitors, FANGS, CLAWS and PLUME, which aims at investigating the backgrounds near the interacting point. The Phase 2 vertex detector integration was practiced and the combined beam tests were accomplished at DESY. In this talk, the status of the Phase 2 vertex detector and the beam tests results are presented.