This paper presents the characterisation and testing of the first wafer-scale monolithic stitched sensor (MOSS) prototype developed for the ALICE ITS3 upgrade that is to be installed during the LHC Long Shutdown 3 (2026-2030). The MOSS chip design is driven by the truly cylindrical detector geometry that imposes that each layer is built out of two wafer-sized, bent silicon chips. The stitching technique is employed to fabricate sensors with dimensions of 1.4 cm x 25.9 cm, thinned to 50 mu m. The chip architecture, the in-pixel front-end, the laboratory and in-beam characterisation, the susceptibility to single-event effects, and the series testing are discussed. The testing campaign validates the design of a wafer-scale stitched sensor and the performance of the pixel matrix to be within the ITS3 requirements. The MOSS chip demonstrates the feasibility of the ITS3 detector concept and provides insights for further optimisation and development.

The OCTOPUS project addresses the development and characterization of monolithic active pixel sensors in the TPSCo 65 nm ISC technology in view of vertexing applications at a future lepton collider. Meeting the corresponding requirements – outlined in the ECFA detector road map – will necessitate the simulation, design, and testing of prototypes and a demonstrator chip in this very process. This work reviews the literature on existing prototypes, summarizing their design characteristics, properties, and performance in charged-particle detection, and provides an overview of previous simulation efforts. The presented results suggest the feasibility of the endeavor while showcasing challenges, the need for further investigations, and providing a foundation for imminent design choices.

The OCTOPUS project addresses the development and characterization of monolithic active pixel sensors in the TPSCo 65nm ISC technology in view of vertexing applications at a future lepton collider. Meeting the corresponding requirements—outlined in the ECFA detector road map—will necessitate the simulation, design, and testing of prototypes and a demonstrator chip in this very process.This work reviews the literature on existing prototypes, summarizing their design characteristics, properties, and performance in charged-particle detection, and provides an overview of previous simulation efforts. The presented results suggest the feasibility of the endeavor while showcasing challenges, the need for further investigations, and providing a foundation for imminent design choices.

MIMOSIS is a CMOS Monolithic Active Pixel Sensor developed to equip the Micro Vertex Detector of the Compressed Baryonic Matter (CBM) experiment at FAIR/GSI. The sensor will combine an excellent spatial precision of 5 µm with a time resolution of ∼5 µs and provide a peak hit rate capability of ∼ 80 MHz/cm 2 . To fulfill its task, MIMOSIS will have to withstand ionising radiation doses of ∼ 5 MRad and fluences of ∼ 7 × 10 13 n eq /cm 2 . This paper introduces the reticle size full feature sensor prototype MIMOSIS-2.1, which was improved with respect to earlier prototypes by adding on-chip grouping circuits and by improving the analog power grid. Moreover, it features for a first time a 50 μm epitaxial layer, which is found to improve the performances of the non-irradiated device significantly. We discuss the in beam sensor performances as measured during beam tests at the CERN-SPS.

The SuperKEKB collider will undergo a major upgrade at the end of the decade to reach the target luminosity of 6x1035 cm-2s-1, offering the opportunity to install a new fully pixelated vertex detector (VTX) for the Belle II experiment, based on depleted-MAPS sensors. The VTX will be more granular and robust against the expected higher level of machine background and more performant in terms of standalone track finding efficiency. The VTX baseline design includes five depleted-MAPS sensor layers, spanning radii from 14 mm to 140 mm, with a material budget ranging from 0.2% to 0.8% X/X0 per layer. All layers will be equipped with the same OBELIX sensor, designed in the TowerJazz 180 nm technology, with the pixel matrix derived from the TJ-Monopix2 sensor originally developed for the ATLAS experiment. The paper will describe the proposed VTX structure and review all project aspects: tests of the TJ-Monopix2 sensor, OBELIX-1 design status, ladder prototype fabrication and tests.

The Micro Vertex Detector (MVD) is the most upstream detector of the fixed-target Compressed Baryonic Matter Experiment (CBM) at the future Facility for Antiproton and Ion Research (FAIR). It enables high-precision low-momentum tracking in direct proximity of the target. Reaching the stringent requirements for the MVD, a material budget of 0.3–0.5% X 0 per layer, operating the dedicated CMOS MAPS ('MIMOSIS') in the target vacuum, the strong magnetic dipole field, and a harsh radiation environment (5 Mrad, 7×10 13 n eq /cm 2 per CBM year), poses an unprecedented integration challenge. In this paper, the integration concept of the detector will be outlined, elaborating on the selection and preparation of materials, assembly procedures, and quality assessment steps in the ongoing preparation of pre-series production and detector commissioning in 2028.

A Large Ion Collider Experiment (ALICE) has been conceived and constructed as a heavy-ion experiment at the LHC. During LHC Runs 1 and 2, it has produced a wide range of physics results using all collision systems available at the LHC. In order to best exploit new physics opportunities opening up with the upgraded LHC and new detector technologies, the experiment has undergone a major upgrade during the LHC Long Shutdown 2 (2019–2022). This comprises the move to continuous readout, the complete overhaul of core detectors, as well as a new online event processing farm with a redesigned online-offline software framework. These improvements will allow to record Pb-Pb collisions at rates up to 50 kHz, while ensuring sensitivity for signals without a triggerable signature.

The ultra-thin and highly granular CMOS Monolithic Active Pixel Sensors (MAPS) are typically optimized for high rate high precision tracking, which implies the use of a very thin active medium and digital readout. Both features hamper using the devices for identifying low momentum particles by means of dE/dx. Still, MAPS feature charge sharing and typically clusters of more than one fired pixel per impinging particles are formed. It was previously shown that the number of fired pixels per cluster scales with the dE/dx, which allowed identifying highly ionizing nuclear fragments [1]. Assuming a sufficiently strong response to different dE/dx, this approach could also be considered for distinguishing minimum ionizing particles (MIP) from light fragments like alpha particles in tracking detectors. In this work, we study this response with particle beams with a dE/dx of up to four times the ones of MIPs, for non-irradiated and irradiated chips, with different sensing nodes as implemented in the MIMOSIS-1 prototype used for the vertex detector of the CBM experiment.

A digital asynchronous logic is proposed as a generic matrix readout for Monolithic active pixel sensors. The architecture is implemented for pixel pitch ranging from 18 to 30 mu m. Post-layout simulations with realistic hit shapes and rates up to 200 MHz/cm2 2 show that time stamping at the 20 ns level can be achieved for a digital power cost below 10 mW/cm2. 2 .

The OBELIX depleted monolithic active CMOS pixel sensor (DMAPS) is currently developed for the upgrade of the vertex detector of the Belle II experiment located at Tsukuba/Japan. The pixel matrix of OBELIX is inherited from the TJ-Monopix2 chip, but the periphery includes additional features to improve performance and allow the integration into a larger detector system. The new features include a trigger unit to process trigger signals, a precision timing module and a possibility to transmit low granularity hit information with low latency to contribute to the Belle II trigger. Additionally, low dropout voltage regulators and an ADC to monitor power consumption and substrate temperature is developed. This paper will focus on the trigger contribution capabilities of the OBELIX chip.

MIMOSIS is a CMOS Monolithic Active Pixel Sensor (CPS) developed to equip the Micro Vertex Detector (MVD) of the Compressed Baryonic Matter (CBM) experiment at FAIR/GSI. The sensor will combine a spatial resolution of -5 µm with a time resolution of 5 µs and provide a peak hit rate capability of ∼80 MHz/cm 2 . To fulfil its task, MIMOSIS will have to withstand ionising radiation doses of ∼5 MRad and fluences of ∼7 × 10 13 n eq /cm 2 per year of operation. The paper summarises major requirements of the CBM-MVD and compares them to the detection performances of the first full scale prototype, called MIMOSIS-1, recently evaluated in the laboratory and with particle beams. The tolerance of the sensor to the expected ionising radiation load was evaluated; the paper describes the measurements performed and their outcome.

The MOnolithic Stitched Sensor (MOSS) is a development prototype chip towards the ITS3 vertexing detector for the ALICE experiment at the LHC. Designed using a 65 nm CMOS Imaging technology, it aims at profiting from the stitching technique to construct a single-die monolithic pixel detector of 1.4 cm x 26 cm. The MOSS prototype is one of the prototypes developed within the CERN-EP R , D framework to learn how to make stitched wafer-scale sensors with satisfactory yield. This contribution will describe some of the design challenges of a stitched pixel sensor , the techniques adopted during the development of this prototype.

The long term goal of the CERN Experimental Physics Department R&D on monolithic sensors is the development of sub-100nm CMOS sensors for high energy physics. The first technology selected is the TPSCo 65nm CMOS imaging technology. A first submission MLR1 included several small test chips with sensor and circuit prototypes and transistor test structures. One of the main questions to be addressed was how to optimize the sensor in the presence of significant in-pixel circuitry. In this paper this optimization is described as well as the experimental results from the MLR1 run confirming its effectiveness. A second submission investigating wafer-scale stitching has just been completed. This work has been carried out in strong synergy with the ITS3 upgrade of the ALICE experiment.

Being installed as close as 5.5 mm to the beam axis, the Micro Vertex Detector (MVD) of the CBM experiment will be exposed to a sizable flow of heavy beam ions and nuclear fragments. The CMOS Monolithic Active Pixel Sensor for the MVD, MIMOSIS, must resist the related heavy ion impacts without permanent damage or frequent interrupt of operation as caused by single event effects (SEE). We motivate the requirements on the sensor and introduce our concept for protecting the device against SEEs. Moreover, we report the results of a related test campaign carried out with the first full size sensor prototype, MIMOSIS-1, and different heavy ion beams at GSI.

A novel approach for designing the next generation of vertex detectors foresees to employ wafer-scale sensors that can be bent to truly cylindrical geometries after thinning them to thicknesses of 20-40$\mu$m. To solidify this concept, the feasibility of operating bent MAPS was demonstrated using 1.5$\times$3cm ALPIDE chips. Already with their thickness of 50$\mu$m, they can be successfully bent to radii of about 2cm without any signs of mechanical or electrical damage. During a subsequent characterisation using a 5.4GeV electron beam, it was further confirmed that they preserve their full electrical functionality as well as particle detection performance. In this article, the bending procedure and the setup used for characterisation are detailed. Furthermore, the analysis of the beam test, including the measurement of the detection efficiency as a function of beam position and local inclination angle, is discussed. The results show that the sensors maintain their excellent performance after bending to radii of 2cm, with detection efficiencies above 99.9% at typical operating conditions, paving the way towards a new class of detectors with unprecedented low material budget and ideal geometrical properties.

This paper describes the deployment and optimization process of triple-module redundancy (TMR) under high design constraints against single-event upset (SEU) and single-event transient (SET). It includes modelling of single-event effect (SEE) pulses with TCAD mesh model, TMR deployment strategies, and verification methods. The simulation result shows that the prototype system with optimized TMR deployment has high reliability with respect to design requirements. The system can run for more than 5 years without critical errors with an equivalent error rate in the working environment is lower than 10$^{-9}$ .

The Micro Vertex Detector (MVD) of the future Compressed Baryonic Matter (CBM) experiment at FAIR will have to provide a spatial precision of ∼5μm in combination with a material budget of 0.3%–0.5%X0 for a full detector station. Simultaneously, it will have to handle the rate and radiation load of operating the fixed target experiment at an average collision rate of 100kHz (4–10AGeV Au+Au collisions) or 10MHz (up to 28GeV p-A collisions). The harsh requirements call for a dedicated detector technology, which is the next generation CMOS Monolithic Active Pixel Sensor MIMOSIS. We report about the requirements for the sensor, introduce the design approach being followed to cope with it and show first test results from a first sensor prototype called MIMOSIS-0 .