Abstract
The Belle II experiment features a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric e+e− collider at KEK in Tsukuba, Japan. The accelerator completed its first phase of commissioning in 2016, and the Belle II detector saw its first electron-positron collisions in April 2018. Belle II features a newly designed silicon vertex detector based on double-sided strip layers and DEPFET pixel layers. A subset of the vertex detector was operated in 2018 to determine background conditions (Phase 2 operation). The collaboration completed full detector installation in January 2019, and the experiment started full data taking. This paper will report on the final arrangement of the silicon vertex detector part of Belle II with a focus on online monitoring of detector conditions and data quality, on the design and use of diagnostic and reference plots, and on integration with the software framework of Belle II. Data quality monitoring plots will be discussed with a focus on simulation and acquired cosmic and collision data.
Highlights
The Belle II experiment uses the asymmetric (4 GeV e+, 7 GeV e−) SuperKEKB collider at the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan
The full installation of the vertex detector was completed in January 2019, and the detector took its first physics collision data in March 2019
Pixels (Fig. 2) are read and signals are processed with the Drain Current Digitizer (DCD) and Data Handling Processor (DHP) chips mounted on the sensor ladder
Summary
The Belle II experiment uses the asymmetric (4 GeV e+, 7 GeV e−) SuperKEKB collider at the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan. The design peak luminosity is 8 × 1035 cm−2s−1, about 40 times larger than in the previous Belle experiment, aiming at an integrated luminosity of 50 ab−1 [2]. The requirements on the new Belle II vertex detector were high: it had to achieve excellent vertexing and tracking capabilities at higher event rates, beam backgrounds, considerable noise occupancy, and radiation damage. The vertex detector, VXD (Fig. 1), is one of the critical determinants of the Belle II physics performance. The full installation of the vertex detector was completed in January 2019, and the detector took its first physics collision data in March 2019
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
