Novel Silicon n-in-p Pixel Sensors for the future ATLAS Upgrades

In view of the LHC upgrade phases towards HL-LHC the ATLAS experiment plans to upgrade the Inner Detector with an all silicon system. The n-in-p silicon technology is a promising candidate for the pixel upgrade thanks to its radiation hardness and cost effectiveness, that allow for enlarging the area instrumented with pixel detectors. We present the characterization and performance of novel n-in-p planar pixel sensors produced by CiS (Germany) connected by bump bonding to the ATLAS readout chip FE-I3. These results are obtained before and after irradiation up to a fluence of 10^16 1-MeV n_eq/cm^2, and prove the operability of this kind of sensors in the harsh radiation environment foreseen for the pixel system at HL-LHC. We also present an overview of the new pixel production, which is on-going at CiS for sensors compatible with the new ATLAS readout chip FE-I4.Comment: Preprint submitted to NIM-A Proceedings (Elba 2012

Performance of novel silicon n-in-p planar Pixel Sensors

The performance of novel n-in-p planar pixel detectors, designed for future upgrades of the ATLAS Pixel system is presented. The n-in-p silicon sensors technology is a promising candidate for the pixel upgrade thanks to its radiation hardness and cost effectiveness, that allow for enlarging the area instrumented with pixel detectors. The n-in-p modules presented here are composed of pixel sensors produced by CiS connected by bump-bonding to the ATLAS readout chip FE-I3. The characterization of these devices has been performed before and after irradiation up to a fluence of 5 x 10**15 1 MeV neq cm-2 . Charge collection measurements carried out with radioactive sources have proven the functioning of this technology up to these particle fluences. First results from beam test data with a 120 GeV/c pion beam at the CERN-SPS are also discussed, demonstrating a high tracking efficiency of (98.6 \pm 0.3)% and a high collected charge of about 10 ke for a device irradiated at the maximum fluence and biased at 1 kV.Comment: Preprint submitted to Nuclear Instruments and Methods A. 7 pages, 13 figure

Radiation hardness studies of neutron irradiated CMOS sensors fabricated in the ams H18 high voltage process

High voltage CMOS detectors (HVCMOSv3), fabricated in the ams H18 high voltage process, with a substrate resistivity of 10 Ω·cm were irradiated with neutrons up to a fluence of 2×1016 neq/cm2 and characterized using edge-TCT. It was found that, within the measured fluence range, the active region and the collected charge reach a maximum at about 7×1015 neq/cm2 to decrease to the level of the unirradiated detector after 2×1016 neq/cm2

Recent technological developments on LGAD and iLGAD detectors for tracking and timing applications

Proceeding of the 10th International “Hiroshima” Symposium on the Development and Application of Semiconductor Tracking Detectors.-- et al.This paper reports the latest technological development on the Low Gain Avalanche Detector (LGAD) and introduces a new architecture of these detectors called inverse-LGAD (iLGAD). Both approaches are based on the standard Avalanche Photo Diodes (APD) concept, commonly used in optical and X-ray detection applications, including an internal multiplication of the charge generated by radiation. The multiplication is inherent to the basic n–p–p structure, where the doping profile of the p layer is optimized to achieve high field and high impact ionization at the junction. The LGAD structures are optimized for applications such as tracking or timing detectors for high energy physics experiments or medical applications where time resolution lower than 30 ps is required. Detailed TCAD device simulations together with the electrical and charge collection measurements are presented through this work.This work was developed in the framework of the CERN RD50 collaboration and financed by the Spanish Ministry of Economy and Competitiveness through the Particle Physics National Program (FPA2013-48308-C2-2-P, FPA2014-55295-C3-2-R and FPA2013-48387-C6-1-P). This project has received funding from the European Union's Horizon 2020 Research and Innovation program under Grant Agreement no. 654168 (AIDA-2020).Open Access funded by CERN.Peer Reviewe

Prototype ATLAS IBL Modules using the FE-I4A Front-End Readout Chip

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.Comment: 45 pages, 30 figures, submitted to JINS

Characterization of proton irradiated 3D-DDTC pixel sensor prototypes fabricated at FBK

In this paper we discuss results relevant to 3D Double-Side Double Type Column (3D-DDTC) pixel sensors fabricated at FBK (Trento, Italy) and oriented to the ATLAS upgrade. Some assemblies of these sensors featuring different columnar electrode configurations (2, 3, or 4 columns per pixel) and coupled to the ATLAS FEI3 read-out chip were irradiated up to large proton fluences and tested in laboratory with radioactive sources. In spite of the non optimized columnar electrode overlap, sensors exhibit reasonably good charge collection properties up to an irradiation fluence of 2 x 10**15 neq/cm2, while requiring bias voltages in the order of 100 V. Sensor operation is further investigated by means of TCAD simulations which can effectively explain the basic mechanisms responsible for charge loss after irradiation.Comment: Preprint submitted to Nuclear Instruments and Methods A, 11 pages, 13 fig

Planar pixel sensors for the ATLAS tracker upgrade at HL-LHC

AbstractThe ATLAS Planar Pixel Sensor R&D Project is a collaboration of 17 institutes and more than 80 scientists. Their goal is to explore the operation of planar pixel sensors for the tracker upgrade at the High Luminosity-Large Hadron Collider (HL-LHC).This work will give a summary of the achievements on radiation studies with n-in-n and n-in-p pixel sensors, bump-bonded to ATLAS FE-I3 and FE-I4 read-out chips. The summary includes results from tests with radioactive sources and tracking efficiencies extracted from test beam measurements. Analysis results of 2×1016neqcm−2 and 1×1016neqcm−2 (1MeV neutron equivalent) irradiated n-in-n and n-in-p modules confirm the operation of planar pixel sensors for future applications

Studie an bestrahlten Pixeldetektoren für das ATLAS IBL und HL-LHC upgrade

Der steigende Bedarf der Hochenergiephysik nach höherer Luminosität ist die Ursache für die ständigen Bemühungen die eingesetzten Beschleuniger sowie die Experimente an die damit zunehmenden Anforderungen anzupassen. Das Upgrade-Programm der Experimente und der Beschleuniger am CERN umfasst bereits mehrere Ausbaustufen des Large Hadron Colliders (LHCs), die die Luminosität sowie den Energiebereich des Beschleunigers erhöhen werden. Die Experimente am LHC arbeiten gleichzeitig daran, die einzelnen Sub-Detektoren auf die steigenden Anforderungen in den kommenden Jahren vorzubereiten. Speziell Tracking Detektoren müssen in Zukunft für in Hochenergie Physik Experimenten bislang ungesehenen Fluenzen zurechtkommen. Mit dem Anstieg der Fluenz nehmen ebenfalls Strahlenschäden zu, die die Lebensdauer der Detektoren durch abnehmende Leistungsfähigkeit begrenzt. Um diesen Effekt zu kompensieren, werden für die kommenden Upgrade-Schritte neue und strahlenhärtere Detektorkonzepte mit längeren Lebensdauern notwendig. Diese Arbeit konzentriert sich darauf, die Einflüsse von Strahlenschäden auf verschiedene Pixel Sensor Technologien zu untersuchen. Die untersuchten Technologien sind mögliche Kandidaten für den Einsatz im kommenden Updgrade des ATLAS Pixel Detektors sowie für Anwendungen im ATLAS Experiment unter HL-LHC Bedingungen. Die betrachteten Sensoren umfassen verschiedene Designs basierend auf Silizium und Diamant als Sensormaterial. Die untersuchten Silizium Designs beinhalten ein planar Pixel Design, das breits im ATLAS Experiment eingesetzt wird sowie ein 3D Pixel Design, bei dem der Sensor über die gesamte Dicke von Elektroden durchzogen ist. Das Diamant Design nutzt auf dem Sensor angebrachte Elektroden ähnlich den planar Designs, wobei Diamant Sensoren aus single- und polykristallinem Material zur Verfügung stehen. Um die Eigenschaften der Sensoren zu untersuchen, werden diese vor und nach Bestrahlung durch Protonen oder Neutronen getestet und charakterisiert. Ein Teil dieser Messungen untersucht das Zusammenspiel der Ausleseelektronik und der Sensoren, um sicherzustellen, dass die Signale auch nach Bestrahlung zuverlässig ausgelesen werden können. Weitere Tests konzentrieren sich auf die Eigenschaften der Sensoren selbst, was zum einen das Strom-Spannungs-Verhalten sowie die Eigenschaften bezüglich der Ladungssammlung umfasst. Hierzu stehen Messungen mit radioaktiven Quellen sowie Teilchenstrahlen aus Pionen und Elektronen zur Verfügung. Abschließend werden die durchgeführten Entwicklungsschritte des für 2013/2014 geplante IBL Upgrades des ATLAS Pixel Detektors zusammengefasst. Dies beinhaltet unter anderem den Ablauf des Qualitätssicherungsverfahrens sowie die Herstellung eines Prototypen der Strukturelemente für die neue Pixeldetektorlage. Mit diesem Prototypen eines sogenanten Staves wurde daraufhin der komplette Stave Produktionsablauf getestet.The constant demand for higher luminosity in high energy physics is the reason for the continuous effort to adapt the accelerators and the experiments. The upgrade program for the experiments and the accelerators at CERN already includes several expansion stages of the Large Hadron Collider (LHC) which will increase the luminosity and the energy of the accelerator. Simultaneously the LHC experiments prepare the individual sub-detectors for the increasing demands in the coming years. Especially the tracking detectors have to cope with fluence levels unprecedented for high energy physics experiments. Correspondingly to the fluence increases the impact of the radiation damage which reduces the life time of the detectors by decreasing the detector performance and efficiency. To cope with this effect new and more radiation hard detector concepts become necessary to extend the life time. This work concentrates on the impact of radiation damage on the pixel sensor technologies to be used in the next upgrade of the ATLAS Pixel Detector as well as for applications in the ATLAS Experiment at HL-LHC conditions. The sensors considered in this work include various designs based on silicon and diamond as sensor material. The investigated designs include a planar silicon pixel design currently used in the ATLAS Experiment as well as a 3D pixel design which uses electrodes penetrating the entire sensor material. The diamond designs implement electrodes similar to the design used by the planar technology with diamond sensors made out of single- and poly-crystalline material. To investigate the sensor properties characterization tests are performed before and after irradiation with protons or neutrons. The measurements are used to determine the interaction between the read-out electronics and the sensors to ensure the signal transfer after irradiation. Further tests focus on the sensor performance itself which includes the analysis of the leakage current behavior and the charge collection properties. The sensor responds to the passing of a charged particle are measured with radioactive sources and particle beams of electrons and pions. To conclude the sensor research the accomplished development stages of the IBL upgrade of the ATLAS pixel detector foreseen for 2013/2014 are summarized. This includes among other things, the progress of the quality assurance process as well as the production of a first stave prototype used to test the stave production process