Resistive switching in Al/Tb/SiO2 nano-multilayers

Màster en Nanociència i Nanotecnologia, Facultat de Física, Universitat de Barcelona, Curs: 2016-2017. Tutors: Blas Garrido Fernández , Oriol Blázquez GómezResistive switching mechanism in memristors offers wide novel properties for nanoelectronics devices. In this work, we report an Al/Tb/SiO2 nano-multilayer memristor. Our devices were fabricated in terms of electron beam evaporation with thicknesses in the order of nanometres. Our devices exhibit memristive behaviour with a high change in resistance which can be cycled up to 20 times at room temperature. The states can persist at least for 140 h. We report bipolar switching with set and reset voltages with a low dispersion during the cycling. We have also studied the impact of the compliance current. Additionally, we studied which conduction mechanism is carrying out the memristive behaviour of our samples, where an Ohmic conduction in the low resistance state is observed and a Schottky fit is applied at the high resistance state. Current-time characteristics of the devices is also shown, where fluctuations and the time of commutation are presented. Finally, we also report the structural characterization of another type of samples, where only the switching mechanism is the aim of study. We have supposed that valence change mechanism is the responsible for the switching mechanis

Overview of CNM LGAD results: Boron Si-on-Si and epitaxial wafers

Low Gain Avalanche Detectors (LGADs) are n-on-p silicon sensors with an extra p-layer below the collection electrode which provides signal amplification. When the primary electrons reach the amplification region new electron-hole pairs are created that enhance the generated signal. The moderate gain of these sensors, together with the relatively thin active region, provide precise time information for minimum ionizing particles. To mitigate the effect of pile-up at the HL-LHC the ATLAS and CMS experiments have chosen the LGAD technology for the High Granularity Timing Detector (HGTD) and for the End-Cap Timing Layer (ETL), respectively. A full characterization of recent productions of LGAD sensors fabricated at CNM has been carried out before and after neutron irradiation up to 2.5 $\times$ 10$^{15}$ n$_{eq}$/cm$^{2}$ . Boron-doped sensors produced in epitaxial and Si-on-Si wafers have been studied. The results include their electrically characterization (IV and bias voltage stability) and performance studies (charge and time resolution) for single pad devices with a Sr-90 radioactive source set-up. The behaviour of the Inter-Pad region for irradiated 2 $\times$ 2 LGAD arrays, using the Transient Current Technique (TCT), is shown. The results indicate that the Si-on-Si devices with higher resistivity perform better than the epitaxial ones

Low Gain Avalanche Detectors (LGADs and iLGADs) for High-Energy Physics and Synchrotron Applications

Aquesta tesi presenta el desenvolupament de Detectors d'Allau de Guany Moderat (LGAD) a l'IMB-CNM (CSIC) per al seu ús en experiments de física d'altes energies i aplicacions de sincrotró. El Gran Col·lisionador d'Hadrons (LHC) es troba al centre dels esforços de tota la comunitat de física de partícules, ja que és l'accelerador de partícules més potent del món. Està previst que l'LHC s'actualitzi (HL-LHC), proporcionant una major lluminositat que donarà lloc a un ventall més ampli de dades recollides en els experiments, establint així un nou paradigma en la física d'altes energies. Tanmateix, es necessiten detectors de partícules capaços de mesurar amb precisió la traça i el temps en què les partícules carregades passen pel detector. El desenvolupament de detectors de radiació no només es basa en experiments de física de partícules, sinó que també s'utilitzen habitualment en sincrotrons, en els quals els feixos de raigs X s'utilitzen per a diverses aplicacions. En ambdues aplicacions, els detectors de radiació estan subjectes a entorns altament radioactius, de manera que el seu rendiment es veu afectat. Per tant, hi ha el compromís d'optimitzar el disseny d'aquests detectors perquè siguin capaços d'oferir un rendiment òptim en aquestes condicions. Aquest treball descriu el disseny, la fabricació i la caracterització dels detectors LGAD per al seu ús al HL-LHC. A més, s'han optimitzat i fabricat altres variants com el LGAD invers (iLGAD) o el nLGAD (LGAD amb substrats de tipus n) per cobrir una àmplia gamma d'aplicacions dins de la detecció de partícules carregades i de raigs XEsta tesis presenta el desarrollo de Detectores de Avalancha con Ganancia Moderada (LGAD) en el IMB-CNM (CSIC) para su uso en experimentos de Física de Altas Energías y aplicaciones en sincrotrón. El Gran Colisionador de Hadrones (LHC) centra los esfuerzos de toda la comunidad de física de partículas, debido a que es el acelerador de partículas más potente del mundo. Está previsto que el LHC sea actualizado (HL-LHC), brindando una mayor luminosidad que conllevará un mayor rango de datos colectados en los experimentos, pudiendo así establecer un nuevo paradigma dentro de la física de altas energías. Sin embargo, son necesarios detectores de partículas capaces de medir precisamente la traza y el tiempo cuando partículas cargadas atraviesan el seno del detector. El desarrollo de detectores de radiación no solo se basa en experimentos en física de partículas, sino que además son comúnmente utilizados en sincrotrones, en los cuales se usan haces de rayos X para diversas aplicaciones. En ambas aplicaciones los detectores de radiación están sujetos a ambientes altamente radioactivos, por lo que su rendimiento se ve afectado. Por lo tanto, existe un compromiso en optimizar el diseño de estos detectores para que sean capaces de brindar un rendimiento óptimo bajo estas condiciones. En este trabajo se describe el diseño, la fabricación y la caracterización de detectores LGAD para ser usados en el HL-LHC. Además, otras variantes como el LGAD Inverso (iLGAD) o el nLGAD (LGAD con sustratos tipo n) se han optimizado y fabricado para cubrir un amplio rango de aplicaciones dentro de la detección de partículas cargadas y rayos X.This thesis presents the development of Low Gain Avalanche Detectors (LGAD) at IMB-CNM (CSIC) for use in High Energy Physics experiments and synchrotron applications. The Large Hadron Collider (LHC) is at the centre of the efforts of the entire particle physics community, as it is the most powerful particle accelerator in the world. It is planned that the LHC will be upgraded (HL-LHC), providing a higher luminosity that will lead to a wider range of data collected in the experiments, thus establishing a new paradigm in high-energy physics. However, particle detectors capable of precisely measuring the trace and time when charged particles pass through the detector are needed. The development of radiation detectors is not only based on experiments in particle physics, but they are also commonly used in synchrotrons, in which X-ray beams are used for various applications. In both applications, radiation detectors are subject to highly radioactive environments, so their performance is affected. Therefore, there is a commitment to optimise the design of these detectors so that they are able to provide optimum performance under these conditions. This paper describes the design, fabrication and characterisation of LGAD detectors for use in the HL-LHC. In addition, other variants such as the Inverse LGAD (iLGAD) or the nLGAD (LGAD with n-type substrates) have been optimised and fabricated to cover a wide range of applications within charged particle and X-ray detection.Universitat Autònoma de Barcelona. Programa de Doctorat en Físic

Low Gain Avalanche Detectors (LGADs and iLGADs) for High-Energy Physics and Synchrotron Applications

Aquesta tesi presenta el desenvolupament de Detectors d'Allau de Guany Moderat (LGAD) a l'IMB-CNM (CSIC) per al seu ús en experiments de física d'altes energies i aplicacions de sincrotró. El Gran Col·lisionador d'Hadrons (LHC) es troba al centre dels esforços de tota la comunitat de física de partícules, ja que és l'accelerador de partícules més potent del món. Està previst que l'LHC s'actualitzi (HL-LHC), proporcionant una major lluminositat que donarà lloc a un ventall més ampli de dades recollides en els experiments, establint així un nou paradigma en la física d'altes energies. Tanmateix, es necessiten detectors de partícules capaços de mesurar amb precisió la traça i el temps en què les partícules carregades passen pel detector. El desenvolupament de detectors de radiació no només es basa en experiments de física de partícules, sinó que també s'utilitzen habitualment en sincrotrons, en els quals els feixos de raigs X s'utilitzen per a diverses aplicacions. En ambdues aplicacions, els detectors de radiació estan subjectes a entorns altament radioactius, de manera que el seu rendiment es veu afectat. Per tant, hi ha el compromís d'optimitzar el disseny d'aquests detectors perquè siguin capaços d'oferir un rendiment òptim en aquestes condicions. Aquest treball descriu el disseny, la fabricació i la caracterització dels detectors LGAD per al seu ús al HL-LHC. A més, s'han optimitzat i fabricat altres variants com el LGAD invers (iLGAD) o el nLGAD (LGAD amb substrats de tipus n) per cobrir una àmplia gamma d'aplicacions dins de la detecció de partícules carregades i de raigs XEsta tesis presenta el desarrollo de Detectores de Avalancha con Ganancia Moderada (LGAD) en el IMB-CNM (CSIC) para su uso en experimentos de Física de Altas Energías y aplicaciones en sincrotrón. El Gran Colisionador de Hadrones (LHC) centra los esfuerzos de toda la comunidad de física de partículas, debido a que es el acelerador de partículas más potente del mundo. Está previsto que el LHC sea actualizado (HL-LHC), brindando una mayor luminosidad que conllevará un mayor rango de datos colectados en los experimentos, pudiendo así establecer un nuevo paradigma dentro de la física de altas energías. Sin embargo, son necesarios detectores de partículas capaces de medir precisamente la traza y el tiempo cuando partículas cargadas atraviesan el seno del detector. El desarrollo de detectores de radiación no solo se basa en experimentos en física de partículas, sino que además son comúnmente utilizados en sincrotrones, en los cuales se usan haces de rayos X para diversas aplicaciones. En ambas aplicaciones los detectores de radiación están sujetos a ambientes altamente radioactivos, por lo que su rendimiento se ve afectado. Por lo tanto, existe un compromiso en optimizar el diseño de estos detectores para que sean capaces de brindar un rendimiento óptimo bajo estas condiciones. En este trabajo se describe el diseño, la fabricación y la caracterización de detectores LGAD para ser usados en el HL-LHC. Además, otras variantes como el LGAD Inverso (iLGAD) o el nLGAD (LGAD con sustratos tipo n) se han optimizado y fabricado para cubrir un amplio rango de aplicaciones dentro de la detección de partículas cargadas y rayos X.This thesis presents the development of Low Gain Avalanche Detectors (LGAD) at IMB-CNM (CSIC) for use in High Energy Physics experiments and synchrotron applications. The Large Hadron Collider (LHC) is at the centre of the efforts of the entire particle physics community, as it is the most powerful particle accelerator in the world. It is planned that the LHC will be upgraded (HL-LHC), providing a higher luminosity that will lead to a wider range of data collected in the experiments, thus establishing a new paradigm in high-energy physics. However, particle detectors capable of precisely measuring the trace and time when charged particles pass through the detector are needed. The development of radiation detectors is not only based on experiments in particle physics, but they are also commonly used in synchrotrons, in which X-ray beams are used for various applications. In both applications, radiation detectors are subject to highly radioactive environments, so their performance is affected. Therefore, there is a commitment to optimise the design of these detectors so that they are able to provide optimum performance under these conditions. This paper describes the design, fabrication and characterisation of LGAD detectors for use in the HL-LHC. In addition, other variants such as the Inverse LGAD (iLGAD) or the nLGAD (LGAD with n-type substrates) have been optimised and fabricated to cover a wide range of applications within charged particle and X-ray detection

Safety of the oral factor XIa inhibitor asundexian compared with apixaban in patients with atrial fibrillation (PACIFIC-AF). a multicentre, randomised, double-blind, double-dummy, dose-finding phase 2 study

Background: Direct-acting oral anticoagulant use for stroke prevention in atrial fibrillation is limited by bleeding concerns. Asundexian, a novel, oral small molecule activated coagulation factor XIa (FXIa) inhibitor, might reduce thrombosis with minimal effect on haemostasis. We aimed to determine the optimal dose of asundexian and to compare the incidence of bleeding with that of apixaban in patients with atrial fibrillation. Methods: In this randomised, double-blind, phase 2 dose-finding study, we compared asundexian 20 mg or 50 mg once daily with apixaban 5 mg twice daily in patients aged 45 years or older with atrial fibrillation, a CHA2DS2-VASc score of at least 2 if male or at least 3 if female, and increased bleeding risk. The study was conducted at 93 sites in 14 countries, including 12 European countries, Canada, and Japan. Participants were randomly assigned (1:1:1) to a treatment group using an interactive web response system, with randomisation stratified by whether patients were receiving a direct-acting oral anticoagulant before the study start. Masking was achieved using a double-dummy design, with participants receiving both the assigned treatment and a placebo that resembled the non-assigned treatment. The primary endpoint was the composite of major or clinically relevant non-major bleeding according to International Society on Thrombosis and Haemostasis criteria, assessed in all patients who took at least one dose of study medication. This trial is registered with ClinicalTrials.gov, NCT04218266, and EudraCT, 2019-002365-35. Findings: Between Jan 30, 2020, and June 21, 2021, 862 patients were enrolled. 755 patients were randomly assigned to treatment. Two patients (assigned to asundexian 20 mg) never took any study medication, resulting in 753 patients being included in the analysis (249 received asundexian 20 mg, 254 received asundexian 50 g, and 250 received apixaban). The mean age of participants was 73·7 years (SD 8·3), 309 (41%) were women, 216 (29%) had chronic kidney disease, and mean CHA2DS2-VASc score was 3·9 (1·3). Asundexian 20 mg resulted in 81% inhibition of FXIa activity at trough concentrations and 90% inhibition at peak concentrations; asundexian 50 mg resulted in 92% inhibition at trough concentrations and 94% inhibition at peak concentrations. Ratios of incidence proportions for the primary endpoint were 0·50 (90% CI 0·14–1·68) for asundexian 20 mg (three events), 0·16 (0·01–0·99) for asundexian 50 mg (one event), and 0·33 (0·09–0·97) for pooled asundexian (four events) versus apixaban (six events). The rate of any adverse event occurring was similar in the three treatment groups: 118 (47%) with asundexian 20 mg, 120 (47%) with asundexian 50 mg, and 122 (49%) with apixaban. Interpretation: The FXIa inhibitor asundexian at doses of 20 mg and 50 mg once daily resulted in lower rates of bleeding compared with standard dosing of apixaban, with near-complete in-vivo FXIa inhibition, in patients with atrial fibrillation. Funding: Bayer