Recent developments and future perspectives in 3D silicon radiation sensors

Silicon Sensor Technologies for the ATLAS IBL Upgrade

3D trenched-electrode pixel sensors: Design, technology and initial results

The ATLAS collaboration will upgrade its semiconductor pixel tracking detector with a new Insertable B-layer (IBL) between the existing pixel detector and the vacuum pipe of the Large Hadron Collider. The extreme operating conditions at this location have necessitated the development of new radiation hard pixel sensor technologies and a new front-end readout chip, called the FE-I4. Planar pixel sensors and 3D pixel sensors have been investigated to equip this new pixel layer, and prototype modules using the FE-I4A have been fabricated and characterized using 120 GeV pions at the CERN SPS and 4 GeV positrons at DESY, before and after module irradiation. Beam test results are presented, including charge collection efficiency, tracking efficiency and charge sharing.

The High Luminosity LHC upgrade demands enhanced tracking, prompting a complete replacement of ATLAS's Inner Detector with the all-silicon Inner Tracker (ITk). Spanning 33–291 mm from the beam pipe, ITk will use hybrid pixel detectors with 65 nm CMOS chips. The inner region, facing extreme radiation, will feature 3D pixel sensors due to their superior radiation tolerance, while the outer regions will use planar sensors. The production of 3D sensors is distributed among two vendors, FBK and SINTEF. The ITk linear triplet module consists of three hybrids (readout chip bump-bonded to a 3D pixel sensor) mounted on a flexible PCB. Extensive testing has been carried out on a linear triplet module in 2025 at CERN's test beam facilities, using 120 GeV pion beams to validate its performance under HL-LHC conditions. The most recent results of the module studied after irradiation will be presented here.

The ATLAS Insertable B-Layer (IBL) is the innermost layer of pixel detectors, and was installed in May 2014 at a radius of 3.3 cm from the beam axis, between the existing Pixel detector and a new smaller radius beam-pipe. The new detector, built to cope with high radiation and occupancy, is the first large scale application of 3D sensors and CMOS 130 nm technology. The IBL detector construction was completed within about two years (2012 – 2014), and the key features and challenges met during the IBL project are presented, as well as its commissioning and operational experience at the LHC.

Commissioning of the read-out driver (ROD) card for the ATLAS IBL detector and upgrade studies for the pixel Layers 1 and 2

Origami-inspired highly stretchable and breathable 3D wearable sensors for in-situ and online monitoring of plant growth and microclimate

The principal aim of the AEgIS experiment at CERN is to measure the acceleration of antihydrogen due to Earth's gravitational field. This would be a test of the Weak Equivalence Principle, which states that all bodies fall with the same acceleration independently of their mass and composition. The effect of Earth's gravitational field on antimatter will be determined by measuring the deflection of the path of the antihydrogen from a straight line. The position of the antihydrogen will be found by detecting its annihilation on the surface of a silicon detector. The gravitational measurement in AEgIS will be performed with a gravity module, which includes the silicon detector, an emulsion detector and a scintillating fibre time-of-flight detector. As the experiment attempts to determine the gravitational acceleration with a precision of 1%, a position resolution better than 10 μm is required. Here we present the results of a study of antiproton annihilations in a 3D silicon pixel sensor and compare the results with a previous study using a monolithic active pixel sensor. This work is part of a larger study on different silicon sensor technologies needed for the development of a silicon position detector for the AEgIS experiment. The 3D detector together with its readout electronics have been originally designed for the ATLAS detector at the LHC. The direct annihilation of low energy antiprotons ( ~ 100 keV) takes place in the first few μm of the silicon sensor and we show that the charged products of the annihilation can be detected with the same sensor. The present study also aims to understand the signature of an antiproton annihilation event in segmented silicon detectors and compares it with a GEANT4 simulation model. These results will be used to determine the geometrical and process parameters to be adopted by the silicon annihilation detector to be installed in AEgIS.

The LHC is planning an upgrade program which will bring the luminosity up to about 7.5 × 1034 cm−2s−1 in 2026, with the goal of an integrated luminosity of 3000 fb−1 by the end of 2037. This High Luminosity scenario, HL-LHC, will present new challenges of higher data rates and unprecedented radiation levels for the CMS Inner Tracker (IT): Φ eq = 2 × 1016 cm−2, and 10 MGy, are expected at the inner layer of the pixel detector for 3000 fb−1 integrated luminosity. To maintain or even improve the performance of the present vertex detector, new technologies have to be fully exploited for the so-called Phase-2 upgrade. Among them is the future version of front-end chips in 65-nm CMOS by the CERN RD53 Collaboration which supports small pixel sizes of 50 × 50 or 25 ×100 µm2 and lower charge thresholds ≈ 1000 e−).Thin planar n-in-p type silicon sensors (of thickness 100-150 µm), segmented into pixel sizes of 25 × 100 µm2 or 50 × 50 µm2, are expected to allow for a good detector resolution that is expected to be more robust with respect to radiation damage compared to the Phase-1 detector. For the innermost detector layer, the option to use 3D silicon sensors is pursued, offering intrinsically higher radiation resistance because of the combination of a short charge collection distance with relatively thick sensors.CMS has launched several R&D submissions for the development of suitable silicon sensors at HPK photonics and FBK Trento (planar), and FBK Trento and CNM (3D sensors). We will present results for measurements on such prototype sensors bump bonded to the ROC4Sens R&D readout chip from PSI, Switzerland, and to the RD53A prototype chip, developed by the RD53 Collaboration at CERN. Different pixel cell designs are compared and evaluated in testbeams at DESY and CERN for charge collection, efficiency and spatial resolution before and after irradiation.

Nowadays, 2D imaging techniques have gone through several stages of development in 2D sensor technologies.This probes greater interest in the 2D image feature extraction and classification techniques.One of the main features of 2D image are texture content which is very enthusiastic to study.The proposed strategy is to extract and analyse of texture content of 2D image.In this strategy Dual Tree Complex Wavelet Transform (DTCWT) and Stationary Wavelet Transform (SWT) with Principal Component Analysis (PCA) is implemented to extract the features of the 2D images especially texture content for further analysis.The texture content is analysed with Gray-Level Co-Occurrence Matrix (GLCM) based method which increase the precision of the data obtained which causes better result.

The High Luminosity upgrade of the CERN Large Hadron Collider (HL-LHC) requires new high-radiation tolerant silicon pixel sensors for the innermost part of the tracking detector in the CMS experiment. The innermost layer of the tracker, which is as close as 3 cm from the interaction point, will be exposed to a fluence of3.4× 1016 neqcm-2 during the high-luminosity operation period. The 3D pixel sensor technology has been proven to be the best option for such a layer in terms of radiation tolerance and low power consumption. An extensive program aiming at 3D pixel sensors has been carried out in the context of the CMS tracker R&D activities. The sensors have been produced by Fondazione Bruno Kessler (Trento, Italy) and Centro Nacional de Microelectrónica (Barcelona, Spain). They are connected with the CROCv1 readout chip, which is a prototype of the final version. The modules have been tested in beams at CERN and DESY, before and after irradiation up to an equivalent fluence of about1.6 × 1016 neqcm-2. An overview of the results obtained in the latest beam test experiments is presented, including hit detection efficiency and spatial resolution. The analysis of collected data shows excellent performance, with around 98% hit detection efficiencies measured after irradiation.

During the first LHC long shutdown (2013/14) a new innermost pixel layer will be added to the present ATLAS Pixel Detector. The Insertable B-Layer (IBL) is a high-reliability, ultra light and radiation hard Pixel Detector assembled with 3D n-in-p and planar n-in-n pixel sensors. Facing the effects of increased luminosity and radiation damage, IBL is expected to improve the b-tagging efficiency, help with pattern recognition performance and add tracking precision with respect to the current detector. Single and double chip modules are loaded on local mechanical support, in the form of 14 staves arranged in cylindrical barrel around the beam pipe. The production of the modules has already started, aiming for a total production of 24 staves including spares. Systematic Quality Assurance (QA) and Quality Control (QC) plans concerning modules, staves and flex from production to final assembly have been put in place. QA is performed in several collaborating institutes and final validation before installation in the ATLAS experiment will be carried out at CERN. Dedicated set-ups have been constructed in order to perform the full chain of QAlQC tests on the production staves. A CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> cooling system is used to cool the pixel modules down to -35°C and an electronic chain similar to the final one has been developed. Furthermore a linear motion system carrying two 241 Am sources with an activity of 41 MBq each is mounted over the stave in order to perform a final characterization of the sensor's performance. The realization of source scans on the 24 production staves permits to analyze the response of sensors to radiation, to easily identify dead pixels, and to provide data for an eventual re-calibration of the charge calibration. The setup and first results obtained on prototype staves are described in detail.

The upgrade for ATLAS detector will undergo different phase towards super-LHC. The first upgrade for the Pixel detector will consist of the construction of a new pixel layer which will be installed during the first shutdown of the LHC machine (LHC phase-I upgrade). The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of 3.3 cm. The IBL will require the development of several new technologies to cope with increase of radiation or pixel occupancy and also to improve the physics performance which will be achieved by reducing the pixel size and of the material budget. Three different promising sensor technologies (planar-Si, 3D-Si and diamond) are currently under investigation for the pixel detector. An overview of the project with particular emphasis on pixel module is presented in this paper.

The High Voltage CMOS (HV-CMOS) sensors are extensively investigated by the ATLAS collaboration for the High-Luminosity LHC (HL-LHC) upgrade of the Inner Tracker (ITk) detector. The HV-CMOS technology is a commercial integrated circuit process with the advantages of monolithic readout and fast charge collection. A front-end test platform of CaRIBOu (Control and Readout Itk BOard) and a testbeam Telescope based on the ATLAS IBL (Insertable B-Layer) silicon pixel modules, have been developed for the HV-CMOS sensor study and characterization in testbeam experiments. The Front-End LInk eXchange (FELIX) system is a new approach to function as the gateway between detector front-end electronics and the commodity switched network in the ATLAS upgrade. A FELIX based readout system has been developed for both the CaRIBOu and the testbeam Telescope. It has been deployed successfully in the testbeam at the CERN SPS H8 beamline in August 2017. The test results show that the readout system is capable of sensor calibration and readout of a high-density pixel detector with high trigger rate in testbeam experiments.

Recent developments of versatile mobile robots demand a precise and complete volumetric representation of space for path and mission planning. However, the immense amount of accumulated raw data points from 3D sensors quickly becomes unmanageable, thereby becoming infeasible regarding memory footprint and navigation itself. To abstract the necessary information into a usable representation for navigation, usually volumetric grid maps are applied. Although these approaches solve the memory and handling issues, current implementations tend to require high computational time for the insertion of new data. As a result the generated maps are often not up to date and incomplete due to dropped sensor data. This greatly impairs their usefulness for navigating robot systems in dynamically changing environments. In order to solve these issues we propose a novel probabilistic mapping framework based on OpenVDB, which is a hierarchical tree structure with efficient access methods to discretized volumetric data. By utilizing the fast direct access to the bitmasks of the underlying OpenVDB data structure, a significant performance boost for data insertion is achieved. Thus, enabling real-time processing of the incoming raw 3D sensor data. An in-depth evaluation of the proposed framework is provided, including a performance and memory footprint comparison against the often employed OctoMap framework. The evaluation reveals, that the presented VDB-Mapping is able to efficiently process long range data on high resolution grids.