Beam background at SuperkEKB during phase 2 operations

The SuperKEKB accelerator, the upgrade of the KEKB machine, will operate at an unprecedented instantaneous luminosity of 8 × 1035cm−2s−1, providing the Belle II ex- periment an expected integrated luminosity of about 50ab−1 in ten years of operation. With the increased luminosity, the beam background is expected to grow significantly with respect to KEKB, leading, among other effects, to possible damage of detector components and suppression of signal events. We present studies done during the Phase 2 oper- ation of SuperKEKB to evaluate the contribution of each background source, including the Touschek effect, beam-gas scattering, synchrotron radiation, and injection background. We also present studies performed on collimators and other solutions adopted to mitigate beam backgrounds in the inter- action region.