Upgrade of the Belle II Vertex Detector with Depleted Monolithic Active Pixel Sensors

Le résumé fourni par la source

Abstract The Belle II experiment, operating at the SuperKEKB e+e- collider, is developing a new pixelated vertex detector (VTX) to handle an higher luminosity, up to 6 × 1035 cm-2 s-1. The VTX will feature 5–6 layers, with a material budget under 3% of X 0, and will utilize depleted monolithic active pixel sensors. The chip developed for the upgrade of the vertex detector, OBELIX, is based on the TJ-Monopix2 sensor which uses Tower Semiconductor 180 nm CMOS process. OBELIX sensor offers a 33 μm pitch, 50 ns time-stamping, and a digital trigger logic that matches Belle II's 30 kHz trigger rate. The sensor is designed to withstand radiation levels up to 5 × 1014 neq/cm2 and 1 MGy while maintaining low power dissipation (200 mW/cm2). This paper outlines the motivation for the upgrade and the VTX concept, and presents characterisation results and beam test campaigns on the TJ-Monopix2 sensor, including both non-irradiated and irradiated samples, which are crucial for validating key performance characteristics for the OBELIX design.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.