Belle II is an experiment dedicated to explore the new physics beyond the Standard Model of particle physics in the flavor sector at the beam intensity frontier. Belle II aims to collect 50 ab^-1 data (~60 billion B meson pairs) in 10 years operation under the condition of world highest instantaneous luminosity. It is a big challenge to handle such large data flow as for the design of data acquisition (DAQ) system. By considering the physics events need to be triggered when luminosity reaches to 8×10³⁵ cm^-2 s^-1, Belle II DAQ system has been designed to handle 30 kHz trigger rate with about 1% dead time under the raw event size more than 1 MB.
In this presentation, we introduce Belle II DAQ system and its performance during last physics run. On the same time, we developed a PCI-express based high-speed readout system for Belle II DAQ upgrade system. We report the development status and the performance.

Slides