The Silicon Vertex Detector of the Belle II Experiment

The Belle II experiment operating at the asymmetric-energy e+e− SuperKEKB collider, located in Tsukuba (Japan), has been collecting data since March 2019. Its excellent vertexing abilities are provided by the vertex detector, part of which is the silicon-strip vertex detector (SVD) that plays a crucial role in the charged-particle tracking close to the interaction point. The SVD has operated successfully and efficiently over the whole period of data taking so far. In this article, we briefly discuss its purpose, structure and basic description of the front-end electronics. The main quantities related to the SVD performance are presented. The foreseen increase in SuperKEKB luminosity will lead to higher background, so we describe its impact on the SVD performance. A quick overview of the radiation damage campaign is presented to show the predicted behaviour of the sensors subjected to high radiation, whose level is constantly monitored. We also discuss the ongoing software development to account for the high occupancy expected in the future. In particular, the utilization of the SVD hit time information is presented as a very important quantity to suppress off-time background hits and tracks. Finally, the work done during the first long shutdown of SuperKEKB is briefly described, during which a major upgrade of the pixel detector has been successfully done. Resumption of the beam operation is expected in early 2024.