Novel 3D Pixel Sensors for the Upgrade of the ATLAS Inner Tracker

The ATLAS experiment will undergo a full replacement of its inner detector to face the challenges posed by the High Luminosity upgrade of the Large Hadron Collider (HL-LHC). The new Inner Tracker (ITk) will have to deal with extreme particle fluences. Due to its superior radiation hardness the 3D silicon sensor technology has been chosen to instrument the innermost pixel layer of ITk, which is the most exposed to radiation damage. Three foundries (CNM, FBK, and SINTEF), have developed and fabricated novel 3D pixel sensors to meet the specifications of the new ITk pixel detector. These are produced in a single-side technology on either Silicon On Insulator (SOI) or Silicon on Silicon (Si-on-Si) bonded wafers by etching both n- and p-type columns from the same side. With respect to previous generations of 3D sensors they feature thinner active substrates and smaller pixel cells of 50 × 50 and 25 × 100 µm2. This paper reviews the main design and technological issues of these novel 3D sensors, and presents their characterization before and after exposure to large radiation doses close to the one expected for the innermost layer of ITk. The performance of pixel modules, where the sensors are interconnected to the recently developed RD53A chip prototype for HL-LHC, has been investigated in the laboratory and at beam tests. The results of these measurements demonstrate the excellent radiation hardness of this new generation of 3D pixel sensors that enabled the project to proceed with the pre-production for the ITk tracker.publishedVersio

Serial Powering Scheme and Performance Analysis for Innermost Layer (L0) for ATLAS ITk modules

After ten years of massive success, the Large Hadron Collider (LHC) at CERN is going for an upgrade to the next phase, the High Luminosity Large Hadron Collider (HL-LHC) which is planned to start its operation in 2029. This is expected to have a fine boost to its performance, with an instantaneous luminosity of 5.0×1034 cm-2s -1 (ultimate value 7.5×1034 cm-2s -1) with 200 average interactions per bunch crossing which will increase the fluences up to more than 1016 neq/cm2, resulting in high radiation damage in ATLAS detector [1]. To withstand this situation, it was proposed to make the innermost layer [L0] of the new Inner Tracker (ITk) with 3D silicon sensor modules, which will have a radiation tolerance of more than 1×1016 neq/cm2 with a TID of 9.9 MGy [2]. Each 3D sensor is bump-bonded to a FrontEnd (FE) chip to form a bare module, and three bare modules are powered in parallel in a triplet module. The L0 layer will have 396 triplet modules. To reduce cable material and improve detector performance, 3 to 5 triplets (depending on the location in the detector) will be powered in series. The FE chip implements a number of features (like a shunt-low-dropout regulator and over-voltage and under-shunt protection) needed to guarantee stable operation of the detector with this powering scheme. In this study, we powered in series 5 triplets based on the pre-production ATLAS FE chip for HL-LHC. We ensured that the chosen operational parameters are within our theoretical specs and result in stable operation of the modules within serial power chain. Triplets were also powered in Low Power mode (LP), used to operate the module at lower current, and their performance was tested without cooling requirement. The performance of the under-shunt and over-voltage protection were also analyzed

Serial Powering Scheme and Performance Analysis for the Innermost Layer (L0) of ATLAS ITk modules

In this study, we powered in series 4 triplets based on the pre-production ATLAS FE chip for HL-LHC. We ensured that the chosen operational parameters were within our theoretical specs and resulted in the stable operation of the modules within the serial power chain. Triplets were also powered in Low Power mode (LP), used to operate the module at a lower current, and their performance was tested without cooling requirements. The performance of the under-shunt and over-voltage protection were also analyzed

Adjusting the LTE structural design to 5G: prospects and challenges

Research directions indicate a behemoth shift will be required from the existing framework to activate 5G in full swing. Current researches are intensively working in this field, however, it will take significant time to reach the ultimate goal. Emphasis has been given on the factors and challenges of 5G, solutions have been proposed accordingly, and some ideas about the architecture have been achieved so far. The work shown in this study is not necessarily a radical one, rather demonstrated the challenges, their possible solutions, and more importantly the proposed solutions are precisely discussed in the context of the architecture. It has been assumed that the whole architecture is closely adjacent to the existing 4G architecture, except that all those elements in the same architecture will be far more capable to enable 5G. Addressing the requirements in a very precise approach, addressing the solutions, and finally locating exactly where they would be applied within the architecture is the main objective

Test of ITk 3D sensor pre-production modules with ITkPixv1.1 chip

ITk detector, the new ATLAS tracking system at High Luminosity LHC, will be equipped with 3D pixel sensor modules in the innermost layer (L0). The pixel cell dimensions will be either 25x100 µm2 (barrel) or 50x50 µm2 (endcap), with one read-out electrode at the centre of a pixel and four bias electrodes at the corners. Sensors from pre-production wafers (50x50 µm2) produced by FBK have been bump bonded to ITkPixv1.1 chip at IZM. Bare modules have been assembled in Genoa on Single Chip Cards and characterized in laboratory and at test beam

Test of ITk 3D sensor pre-production modules with ITkPixv1.1 chip

ITk detector, the new ATLAS tracking system at High Luminosity LHC, will be equipped with 3D pixel sensor modules in the innermost layer (L0). The pixel cell dimensions will be either 25x100 µm2 (barrel) or 50x50 µm2 (endcap), with one read-out electrode at the centre of a pixel and four bias electrodes at the corners. Sensors from pre-production wafers (50x50 µm2) produced by FBK have been bump bonded to ITkPixv1.1 chip at IZM. Bare modules have been assembled in Genoa on Single Chip Cards and characterized in laboratory and at test beam

Qualification of the first preproduction 3D FBK sensors with ITkPixV1\

The ITk detector, the new ATLAS silicon tracking system for High Luminosity LHC, will be equipped with 3D pixel sensor modules in the innermost layer (L0). The pixel cell dimensions will be 25x100 μm² in the barrel and 50x50 μm² in the end-caps, with one read-out electrode at the centre of each pixel and four bias electrodes at the corners. Sensors from pre-production wafers (50x50 μm²) produced by FBK have been bump bonded to ITkPixV1.1 chips at IZM. Bare modules have been assembled in Genoa on Single Chip Cards and characterized in laboratory and at test beams. Few of these modules have been irradiated in Bonn and at the CERN IRRAD facility. Preliminary results of their characterization after irradiation will be shown, including measurements performed during SPS test beam campaigns in Summer 2022

Qualification of the first pre-production 3D FBK sensors with ITkPixV1 readout chip

The ITk detector, the new ATLAS silicon tracking system for the High Luminosity LHC (HL-LHC), will be equipped with 3D pixel sensor modules in the innermost layer (L0). The pixel cell dimensions will be 25×100 μm$^{2}$ in the barrel and 50×50 μm$^{2}$ in the end-caps, with one readout electrode at the centre of each pixel and four bias electrodes at the corners. Sensors from pre-production wafers (50×50 μm$^{2}$) produced by FBK have been bump-bonded to ITkPixV1.1 chips at IZM. Bare modules have been assembled in Genoa on Single Chip Cards (SCCs) and characterized in laboratory measurements and in test beam campaigns. Some of these modules have been irradiated in Bonn and at the CERN IRRAD facility. Preliminary results of their characterization after irradiation are shown, including measurements performed during test beam campaigns at CERN SPS in Summer 2022

Novel 3D Pixel Sensors for the Upgrade of the ATLAS Inner Tracker

The ATLAS experiment will undergo a full replacement of its inner detector to face the challenges posed by the High Luminosity upgrade of the Large Hadron Collider (HL-LHC). The new Inner Tracker (ITk) will have to deal with extreme particle fluences. Due to its superior radiation hardness the 3D silicon sensor technology has been chosen to instrument the innermost pixel layer of ITk, which is the most exposed to radiation damage. Three foundries (CNM, FBK, and SINTEF), have developed and fabricated novel 3D pixel sensors to meet the specifications of the new ITk pixel detector. These are produced in a single-side technology on either Silicon On Insulator (SOI) or Silicon on Silicon (Si-on-Si) bonded wafers by etching both n- and p-type columns from the same side. With respect to previous generations of 3D sensors they feature thinner active substrates and smaller pixel cells of 50 × 50 and 25 × 100 µm2. This paper reviews the main design and technological issues of these novel 3D sensors, and presents their characterization before and after exposure to large radiation doses close to the one expected for the innermost layer of ITk. The performance of pixel modules, where the sensors are interconnected to the recently developed RD53A chip prototype for HL-LHC, has been investigated in the laboratory and at beam tests. The results of these measurements demonstrate the excellent radiation hardness of this new generation of 3D pixel sensors that enabled the project to proceed with the pre-production for the ITk tracker

Novel 3D Pixel Sensors for the Upgrade of the ATLAS Inner Tracker

The ATLAS experiment will undergo a full replacement of its inner detector to face the challenges posed by the High Luminosity upgrade of the Large Hadron Collider (HL-LHC). The new Inner Tracker (ITk) will have to deal with extreme particle fluences. Due to its superior radiation hardness the 3D silicon sensor technology has been chosen to instrument the innermost pixel layer of ITk, which is the most exposed to radiation damage. Three foundries (CNM, FBK, and SINTEF), have developed and fabricated novel 3D pixel sensors to meet the specifications of the new ITk pixel detector. These are produced in a single-side technology on either Silicon On Insulator (SOI) or Silicon on Silicon (Si-on-Si) bonded wafers by etching both n- and p-type columns from the same side. With respect to previous generations of 3D sensors they feature thinner active substrates and smaller pixel cells of 50 × 50 and 25 × 100 µm2. This paper reviews the main design and technological issues of these novel 3D sensors, and presents their characterization before and after exposure to large radiation doses close to the one expected for the innermost layer of ITk. The performance of pixel modules, where the sensors are interconnected to the recently developed RD53A chip prototype for HL-LHC, has been investigated in the laboratory and at beam tests. The results of these measurements demonstrate the excellent radiation hardness of this new generation of 3D pixel sensors that enabled the project to proceed with the pre-production for the ITk tracker