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

[2605.13572] Upgrade of the Belle II Vertex Detector with Depleted Monolithic CMOS Active Pixel Sensors Skip to main content Search Submit Donate Log in Physics > Instrumentation and Detectors arXiv:2605.13572 (physics) [Submitted on 13 May 2026 ( v1 ), last revised 16 Aug 2026 (this version, v2)] Title: Upgrade of the Belle II Vertex Detector with Depleted Monolithic CMOS Active Pixel Sensors Authors: Belle II VTX Collaboration View PDF HTML (experimental) Abstract: The Belle II experiment, operating at the asymmetric SuperKEKB $e^+e^-$ collider, is preparing an upgrade of its vertex detector to cope with an increased luminosity of $6 \times 10^{35}$ cm$^{-2}$s$^{-1}$. The upgraded vertex detector (VTX) will consist of five or six layers of depleted monolithic active pixel sensors (DMAPS), with a total material budget of approximately $3\%$ $X/X_0$. The OBELIX chip, derived from the TJ-Monopix2 sensor and fabricated using Tower-Jazz Semiconductor 180 nm CMOS technology, is being developed for this upgrade. It features a 33 $\mu$m pixel pitch with a time-stamping binning of $50-100$ ns, along with a dedicated digital periphery compatible with the Belle II trigger system, supporting rates up to 30 kHz. The sensor is designed to operate under the high background conditions expected at the target luminosity, with radiation tolerance up to $5 \times 10^{14}$ $n_{eq}$/cm$^2$ and 100 Mrad, while targeting a power density of about 200 mW/cm$^2$. This corresponds to hit rates up to 120 MHz/cm$^2$. Beam test and irradiation studies of TJ-Monopix2 demonstrate that the operating sensor temperature should stay below $40^\circ$C after irradiation up to $5 \times 10^{14}$ $n_{eq}$/cm$^2$. This report reviews the proposed VTX concept, sensor performance, and ongoing R$\&$D activities. Comments: 6 pages, 7 figures, TIPP 2026 conference proceedings Subjects: Instrumentation and Detectors (physics.ins-det) Report number: BELLE2-PROC-2026-011 Cite as: arXiv:2605.13572 [physics.ins-det] (or arXiv:2605.13572v2 [physics.ins-det] for this version) https://doi.org/10.48550/arXiv.2605.13572 Focus to learn more arXiv-issued DOI via DataCite Journal reference: NIM A 1093 (2027) 171963 Related DOI : https://doi.org/10.1016/j.nima.2026.171963 Focus to learn more DOI(s) linking to related resources Submission history From: Vindhyawasini Prasad Dr. [ view email ] [v1] Wed, 13 May 2026 14:09:45 UTC (1,085 KB) [v2] Sun, 16 Aug 2026 23:37:32 UTC (1,085 KB) Full-text links: Access Paper: View PDF HTML (experimental) TeX Source view license Current browse context: physics.ins-det < prev | next > new | recent | 2026-05 Change to browse by: physics References & Citations INSPIRE HEP SciX Google Scholar Semantic Scholar export BibTeX citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer ( What is the Explorer? ) Connected Papers Toggle Connected Papers ( What is Connected Papers? ) Litmaps Toggle Litmaps ( What is Litmaps? ) scite.ai Toggle scite Smart Citations ( What are Smart Citations? ) Code, Data, Media Code, Data and Media Associated with this Article alphaXiv Toggle alphaXiv ( What is alphaXiv? ) Links to Code Toggle CatalyzeX Code Finder for Papers ( What is CatalyzeX? ) DagsHub Toggle DagsHub ( What is DagsHub? ) GotitPub Toggle Gotit.pub ( What is GotitPub? ) Huggingface Toggle Hugging Face ( What is Huggingface? ) ScienceCast Toggle ScienceCast ( What is ScienceCast? ) Demos Demos Replicate Toggle Replicate ( What is Replicate? ) Spaces Toggle Hugging Face Spaces ( What is Spaces? ) Spaces Toggle TXYZ.AI ( What is TXYZ.AI? ) Related Papers Recommenders and Search Tools Link to Influence Flower Influence Flower ( What are Influence Flowers? ) Core recommender toggle CORE Recommender ( What is CORE? ) Author Venue Institution Topic About arXivLabs arXivLabs: experimental projects with community collaborators arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website. Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them. Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs . Which authors of this paper are endorsers? | Disable MathJax ( What is MathJax? ) We gratefully acknowledge support from our major funders , member institutions , and all contributors. About · Help · Contact · Subscribe · Copyright · Privacy · Accessibility · Operational Status (opens in new tab)

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