Investigating the Optical Link Performance of the End-of Substructure Card and Susceptibility to SEUs

Particle physics experiments carried out by CERN attempt to investigate the fundamental forces of matter. One of these experiments is the ATLAS experiment, which studies the proton-proton collisions in the LHC. A series of upgrades are planned to increase the luminosity by a factor of five, leading to the high-luminosity LHC (HL-LHC). This upgrade will increase the potential for new discoveries but brings with it design challenges in relation to the harsh radiation environment and significant data throughput required. The ATLAS experiment is building a new detector to cope with these challenges, titled the Inner Tracker (ITk). A crucial part of this new detector is the End-of-Substructure (EoS) card, which constitutes the interface between the ondetector electronics and the off-detector systems. In addition to the operational challenges, the HL-LHC does not allow for repairs or replacing of EoS cards once operation commences, emphasizing the need for thorough testing and qualification of this component. This thesis focuses on characterizing the performance of the EoS card in the presence of radiation, under non-ideal operating conditions and the impact of optical link parameters. The first set of tests is centered on qualifying the radiation tolerance of the EoS card. The radiation environment within the ITk poses a threat to the stable operation of electronics as energetic particles have the potential to cause erroneous changes in device logic, known as Single Event Upsets (SEU). The SEU susceptibility of the EoS card, with a focus on the Versatile Link Plus Transceiver (VTRx+) component, is studied by irradiating the EoS card with a neutron source with a distributed energy spectrum and a peak energy of 11MeV while performing a bit error rate (BER) test to monitor for radiation induced errors. The second set of tests deals with characterizing the impact of an irregular power supply on the EoS card's performance through simulating noise on the supply lines and monitoring the response in BER. The final set of tests investigates the impact the VTRx+ configuration parameters have on the quality of the optical signal. These tests were carried out at the University of Cape Town (UCT) with the support of DESY, a national research institute in Germany, responsible for the production of the EoS cards. A number of new firmware, software and hardware modules were developed as part of this work in order to carry out the tests required. The most significant of which comprised a novel firmware addition allowing for the evaluation of the optical signal quality with an FPGA. This contribution is now being integrated into the quality control proceedings at DESY, to be used in assessing optical signal quality of the entire set of approximately 1552 EoS cards being produced

Enhancing the value of mortality data for health systems : adding Circumstances Of Mortality CATegories (COMCATs) to deaths investigated by verbal autopsy

The authors thank the MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt) management team for their support of this project. Analyses are based on data collected by the Unit. Support for the Agincourt HDSS site comes from the School of Public Health and Faculty of Health Sciences, University of the Witwatersrand, and the Medical Research Council, South Africa, with core funding from the Wellcome Trust, UK (Grants 058893/Z/99/A; 069683/Z/02/Z; 085477/Z/08/Z) and contributions from the National Institute on Aging (NIA) of the NIH, William and Flora Hewlett Foundation, and Andrew W Mellon Foundation, USA. Conceptualisation of COMCAT was supported through a parent study funded by the Joint Health Systems Research Initiative from Department for International Development (DFID)/Medical Research Council (MRC)/Wellcome Trust/Economic and Social Research Council (ESRC) (MR/N005597/1 and MR/P014844/1).Peer reviewedPublisher PD

ENIGMA and global neuroscience: A decade of large-scale studies of the brain in health and disease across more than 40 countries.

This review summarizes the last decade of work by the ENIGMA (Enhancing NeuroImaging Genetics through Meta Analysis) Consortium, a global alliance of over 1400 scientists across 43 countries, studying the human brain in health and disease. Building on large-scale genetic studies that discovered the first robustly replicated genetic loci associated with brain metrics, ENIGMA has diversified into over 50 working groups (WGs), pooling worldwide data and expertise to answer fundamental questions in neuroscience, psychiatry, neurology, and genetics. Most ENIGMA WGs focus on specific psychiatric and neurological conditions, other WGs study normal variation due to sex and gender differences, or development and aging; still other WGs develop methodological pipelines and tools to facilitate harmonized analyses of "big data" (i.e., genetic and epigenetic data, multimodal MRI, and electroencephalography data). These international efforts have yielded the largest neuroimaging studies to date in schizophrenia, bipolar disorder, major depressive disorder, post-traumatic stress disorder, substance use disorders, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorders, epilepsy, and 22q11.2 deletion syndrome. More recent ENIGMA WGs have formed to study anxiety disorders, suicidal thoughts and behavior, sleep and insomnia, eating disorders, irritability, brain injury, antisocial personality and conduct disorder, and dissociative identity disorder. Here, we summarize the first decade of ENIGMA's activities and ongoing projects, and describe the successes and challenges encountered along the way. We highlight the advantages of collaborative large-scale coordinated data analyses for testing reproducibility and robustness of findings, offering the opportunity to identify brain systems involved in clinical syndromes across diverse samples and associated genetic, environmental, demographic, cognitive, and psychosocial factors

ENIGMA and global neuroscience: A decade of large-scale studies of the brain in health and disease across more than 40 countries

This review summarizes the last decade of work by the ENIGMA (Enhancing NeuroImaging Genetics through Meta Analysis) Consortium, a global alliance of over 1400 scientists across 43 countries, studying the human brain in health and disease. Building on large-scale genetic studies that discovered the first robustly replicated genetic loci associated with brain metrics, ENIGMA has diversified into over 50 working groups (WGs), pooling worldwide data and expertise to answer fundamental questions in neuroscience, psychiatry, neurology, and genetics. Most ENIGMA WGs focus on specific psychiatric and neurological conditions, other WGs study normal variation due to sex and gender differences, or development and aging; still other WGs develop methodological pipelines and tools to facilitate harmonized analyses of "big data" (i.e., genetic and epigenetic data, multimodal MRI, and electroencephalography data). These international efforts have yielded the largest neuroimaging studies to date in schizophrenia, bipolar disorder, major depressive disorder, post-traumatic stress disorder, substance use disorders, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorders, epilepsy, and 22q11.2 deletion syndrome. More recent ENIGMA WGs have formed to study anxiety disorders, suicidal thoughts and behavior, sleep and insomnia, eating disorders, irritability, brain injury, antisocial personality and conduct disorder, and dissociative identity disorder. Here, we summarize the first decade of ENIGMA's activities and ongoing projects, and describe the successes and challenges encountered along the way. We highlight the advantages of collaborative large-scale coordinated data analyses for testing reproducibility and robustness of findings, offering the opportunity to identify brain systems involved in clinical syndromes across diverse samples and associated genetic, environmental, demographic, cognitive, and psychosocial factors

The End-of-Substructure Card for the ATLAS ITk Strip Detector: Status of the Electronics Design and Results from Recent Quality Control Tests

The silicon tracker of the ATLAS experiment will be upgraded for the upcoming High-Luminosity Upgrade of the LHC (HL-LHC). The main building blocks of the new strip tracker are modules that consist of silicon sensors and read-out ASICs, the latter hosted on hybrid PCBs. Up to 14 modules are assembled on carbon-fibre substructures, commonly named staves in the central barrel region and petals in the two end-cap regions, for mechanical support. An End-of-Substructure (EoS) card is located at the end of each substructure and facilitates the transfer of data, power, and control signals between the modules and the off-detector systems. The module front-end ASICs transfer data (up to 28 differential lines at 640 MBit/s) to low-powered GigaBit Transceivers (lpGBT) ASICs on the EoS card. The lpGBT(s) provide data serialisation and use a 10 GBit/s versatile optical link plus transceiver (VTRx+) package to transmit signals to the off-detector systems. To meet the tight integration requirements in the detector, several EoS card designs have been realised. The produced prototypes have been populated with the currently available versions of the lpGBT and VTRx+ ASICs. Here, we present the current status of the EoS cards electronic design, results from extreme temperature, magnetic field and integration tests. Additionally, we discuss the results of detailed investigations into the optical signal quality and introduce a new eye-diagram extraction tool to be used in the Quality Control (QC) procedure that aims to ensure full functionality of the EoS card throughout the entire HL-LHC operation