Yuma Uematsu

10 September 2021
Vertex 2021

Abstract: Since the start of data taking in spring 2019 at the Super-KEKB collider (KEK, Japan) the Silicon Vertex Detector (SVD) has been operated reliably and with high efficiency, providing high-quality data: high signal-to-noise ratio and hit efficiency, as well precise spatial resolution and stability over time allowed to achieve good tracking efficiency. Currently, the occupancy, dominated by background hits, is quite low (about 0.5 % in the innermost layer), causing no problems to the SVD data reconstruction. In view of the operation at higher luminosity foreseen in the next years, specific strategies aiming to preserve the tracking performance have been developed and tested on data. The sampling of the strip amplifier waveform can be reduced, based on the trigger jitter estimated from the calorimeter trigger signal. The good hit-time resolution can be exploited to further improve the robustness against the higher levels of background. The first effects of radiation damage on strip noise, sensor currents, and depletion voltage have been measured, although they do not have any detrimental effect on the performance of the detector. Furthermore, no damage to the SVD is observed after recent sudden and intense bursts of radiation due to beam losses.