OBELIX: A monolithic pixel sensor with triggered readout for the Belle II upgrade

The Upgrade of the Belle II vertex detector (VTX) at the SuperKEKB accelerator in Japan is foreseen to improve tracking performance at the expected high beam backgrounds at target luminosity of 6 × 10 35 cm -2 s -1 . The OBELIX-1 chip is specifically developed for this purpose and used as sensor on all VTX layers. OBELIX-1 is a depleted monolithic active pixel sensor in 180 nm technology. The pixel matrix is inherited from TJ-Monopix2, but the periphery of the chip is entirely reworked. A newly designed 2-stage pixel memory matches Belle II trigger requirements. OBELIX-1 includes LDO regulators and a precision timing module with less than 3 n s resolution. Furthermore, the chip can also contribute to the Belle II trigger system with low latency, low granularity real-time streaming of pixel data in parallel to regular operation. Details of the inner working of the trigger memory are presented, as well as performance simulations to validate the requirements for the VTX Upgrade. The trigger memory has been studied in simulation using realistic scenarios, including Landau distributed charge and clustering to evaluate performance. In order to allow post-production testing, an additional module is presented. This allows the injection of pseudo-random data early in the processing chain, and replaces the need for industry standard scan-chains. It can be used stand-alone or during analog charge injection, in order to reach the full trigger memory during testing.

Authors

Institutions

Publication Details

Journal
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
Published
2025-06-02
DOI
https://doi.org/10.1016/j.nima.2025.170654
Primary Topic
CCD and CMOS Imaging Sensors
Type
article
Field-Weighted Citation Impact
0.00
Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

OBELIX: A monolithic pixel sensor with triggered readout for the Belle II upgrade

D Xu, S. Giroletti, G. Dujany, L. Federici et al.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
CCD and CMOS Imaging Sensors
article

OBELIX: A monolithic pixel sensor with triggered readout for the Belle II upgrade

D Xu, S. Giroletti, G. Dujany, L. Federici, Meike Vogt, H. Krüger, T. Higuchi, W. M. Song, C. Lacasta, P. Pangaud, Y. Buch, S. Mondal, C. Bespin, J. Gong, L. Massaccesi, J. Baudot, Y. Peinaud, D. Fougeron, L. Schall, C. Finck, M. Barbero, A. B. Kaliyar, Franck Morel, M. Bóna, M. Schwickardi, B. Pilsl, G. Rizzo, J. Mazorra de Cos, G. Bertolone, A. Gallas Torreira, T. Kishishita, K.R. Nakamura, G. Traversi, V. Vobbilisetti, P. Stavroulakis, S. Bettarini, R. Sefri, C. Hu-Guo, J. Serrano, P. Breugnon, B. Schwenker, M. Babeluk, C. Mariñas, M. Minuti, L. Corona, J. Dingfelder, E. Riceputi, Arvind Kumar, C. Irmler, K. Hara, F. Forti, M. Massa, R. Boudagga, D. Howgill, A. J. Bevan, X. Y. Gao, L. Molina Bueno, D. Jeans, H. Pham, L. Gaioni, V. Re, G. Casarosa, Y. Onuki, C. Schwanda, F. Bernlochner, A. Fernandez Prieto, I. Ripp-Baudot, Y. Okazaki, A. Gabrielli, D. Auguste, F. Bosi, A. Himmi, M. Karagounis, A. Moggi, J. Bonis, A. Dorokhov, Marcus Winter, L. Ratti, I. Valin, A. Frey, T. Bergauer, P. Barrillon, M. Maushart, S. Wang
article en

Abstract

The Upgrade of the Belle II vertex detector (VTX) at the SuperKEKB accelerator in Japan is foreseen to improve tracking performance at the expected high beam backgrounds at target luminosity of 6 × 10 35 cm -2 s -1 . The OBELIX-1 chip is specifically developed for this purpose and used as sensor on all VTX layers. OBELIX-1 is a depleted monolithic active pixel sensor in 180 nm technology. The pixel matrix is inherited from TJ-Monopix2, but the periphery of the chip is entirely reworked. A newly designed 2-stage pixel memory matches Belle II trigger requirements. OBELIX-1 includes LDO regulators and a precision timing module with less than 3 n s resolution. Furthermore, the chip can also contribute to the Belle II trigger system with low latency, low granularity real-time streaming of pixel data in parallel to regular operation. Details of the inner working of the trigger memory are presented, as well as performance simulations to validate the requirements for the VTX Upgrade. The trigger memory has been studied in simulation using realistic scenarios, including Landau distributed charge and clustering to evaluate performance. In order to allow post-production testing, an additional module is presented. This allows the injection of pseudo-random data early in the processing chain, and replaces the need for industry standard scan-chains. It can be used stand-alone or during analog charge injection, in order to reach the full trigger memory during testing.

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated EquipmentVol. 1080
University of Pisa (IT), Centre National de la Recherche Scientifique (FR), University of Bonn (DE), Austrian Academy of Sciences (AT), Queen Mary University of London (GB), Aix-Marseille Université (FR), Université Paris-Saclay (FR), Institut Pluridisciplinaire Hubert Curien (FR), Institute of High Energy Physics (AT), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (FR), Centrale Méditerranée (FR), Istituto Nazionale di Fisica Nucleare, Sezione di Pisa (IT), Université de Strasbourg (FR), University of Göttingen (DE)
Openalex Percentile: Top 90%
CCD and CMOS Imaging Sensors
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.