Performance of the diamond-based beam-loss monitor system of Belle II

We designed, constructed and have been operating a system based on single-crystal synthetic diamond sensors, to monitor the beam losses at interaction region of SuperKEKB asymmetric-energy electron-positron collider. The records radiation dose-rates in positions close inner detectors Belle II experiment, protects both detector accelerator components against destructive losses, by participating beam-abort system. It also provides complementary information for dedicated studies beam-related backgrounds. describe performance during commissioning first physics data taking.