Beam background evaluation at SuperKEKB and Belle II

The SuperKEKB asymmetric electron-positron collider is the upgrade of the KEKB machine and it is expected to achieve the instantaneous luminosity of 8 × 10 35 cm −2 s −1 , 40 times higher than the record of KEKB. With the increased luminosity, the beam background is expected to grow significantly with respect to KEKB, leading, among other effects, to possible radiation damage of detector components and to performance deterioration of the Belle II detector. SuperKEKB started operating in 2018, with a stepwise reduction of the beam size at the interaction point that has been done in the last two years, studying the evolution of background conditions. We present the studies performed in 2019 to evaluate the contributions of single beam and luminosity background sources, the conditions in which the Belle II detector has been operated so far and the prospects for future operation.