Performance of the Data Handling Hub readout system for the Belle II pixel detector

TL;DR

This paper describes the architecture and performance of the Data Handling Hub system for the Belle II pixel detector, which manages high data rates from the upgraded detector at SuperKEKB.

Contribution

It introduces the design and operational performance of the DHH system tailored for high data throughput in the Belle II experiment.

Findings

DHH effectively manages 20 GByte/s data rate.

System shows reliable operation after one year.

Supports high detector occupancy with efficient readout.

Abstract

The SuperKEKB accelerator in Tsukuba, Japan is providing e$^+$e$^-$ beams for the Belle II experiment since March 2019. To deal with the aimed peak luminosity being forty times higher than the one recorded at Belle, a pixel detector based on DEPFET technology has been installed. It features a long integration time of 20 $\mu$s resulting in an expected data rate of 20 GByte/s (160 GBit/s) at a maximum occupancy of 3 %. To deal with this high amount of data, the data handling hub (DHH) has been developed. It contains all necessary functionality for the control and readout of the detector. In this paper we describe the architecture and features of the DHH system. Further we will show the key performance characteristics after one year of operation.