Letteratura scientifica selezionata sul tema "Non-ionizing displacement dose"

AbstractWhen exposed to radiation, the function of microelectronic devices is not only degraded by single-event phenomena but by cumulative effects. Most of the energy lost by radiation passing through semiconductors is through ionization. Buildup of charge in gate oxide layers and of interface and border traps due to ionization result in semipermanent damage to the device. These effects are known as total ionizing dose effects. A fraction of the energy of the radiation passing through semiconductors is lost to displacement of atoms from their sites in the crystal lattice structure. The buildup of displacement damage with radiation exposure causes gradual but permanent changes in device performance and limits device lifetime in a radiation environment. Displacement damage will be discussed in the context of non-ionizing energy loss.

In this paper, the effects of proton and gamma irradiation on reach-through single-photon avalanche diodes (SPADs) are investigated. The I–V characteristics, gain and spectral response of SPAD devices under proton and gamma irradiation were measured at different proton energies and irradiation bias conditions. Comparison experiments of proton and gamma irradiation were performed in the radiation environment of geosynchronous transfer orbit (GTO) with two different radiation shielding designs at the same total ionizing dose (TID). The results show that after 30 MeV and 60 MeV proton irradiation, the leakage current and gain increase, while the spectral response decreases slightly. The leakage current degradation is more severe under the “ON”-bias condition compared to the “OFF”-bias condition, and it is more sensitive to the displacement radiation damage caused by protons compared to gamma rays under the same TID. Further analysis reveals that the non-elastic and elastic cross-section of protons in silicon is 1.05 × 105 times greater than that of gamma rays. This results in SPAD devices being more sensitive to displacement radiation damage than ionizing radiation damage. Under the designed shielding conditions, the leakage current, gain and spectral response parameters of SPADs do not show significant performance degradation in the orbit.

As a matter of fact, near space radiation environment analysis plays a crucial role in near space physics. With this in mind, this study introduces the types of radiation damage in the near-space radiation environment as well as corresponding protective measures. To be specific, the protective strategy for Total Ionizing Dose (TID) and for Displacement Damage (DD) are similar, focusing on material shielding to mitigate the effects. According to the analysis, the guiding principle for the protection strategy against Single Event Effects (SEE) is risk management, aiming to minimize the probability of catastrophic SEE and to detect and mitigate the impact of non-destructive SEE. Based on the analysis, some measures are proposed accordingly. In fact, current strategies for future radiation protection may involve the use of biological membranes to absorb radiation or the application of quantum mechanics principles to eliminate the effects brought about by radiation. These results shed light on guiding further exploration if near space radiation.

The displacement damage dose (DDD) is a common index used to predict the life of semiconductor devices employed in space-based environments where they will be exposed to radiation. The DDD is commonly estimated from the non-ionizing energy loss based on the Norgett-Robinson-Torrens (NRT) model, although a new definition for a so-called effective DDD considers the molecular dynamic (MD) simulation with the amorphization in semiconductors. The present work developed a new model for calculating the conventional and effective DDD values for silicon carbide (SiC), indium arsenide (InAs), gallium arsenide (GaAs) and gallium nitride (GaN) semiconductors. This model was obtained by extending the displacement per atom tally implemented in the particle and heavy ion transport code system (PHITS). This new approach suggests that the effective DDD is higher than the conventional DDD for arsenic-based compounds due to the amorphization resulting from direct impacts, while this relationship is reversed for SiC because of recombination defects. In the case of SiC and GaN exposed to protons, the effective DDD/conventional DDD ratio decreases with proton energy. In contrast, for InAs and GaAs, this ratio increases to greater than 1 at proton energies up to 100 MeV and plateaus because the defect production efficiency, which is the ratio of the number of stable displacements at the end of collision cascade simulated by MD simulations to the number of defects calculated by NRT model, does not increase at damage energy values above 20 keV. The practical application of this model was demonstrated by calculating the effective DDD values for semiconductors sandwiched between a thin glass cover and an aluminum plate in a low-Earth orbit. The results indicated that the effective DDD could be dramatically reduced by increasing the glass cover thickness to 200 μm, thus confirming the importance of shielding semiconductor devices used in space. This improved PHITS technique is expected to assist in the design of semiconductors by allowing the effective DDD values for various semiconductors having complex geometries to be predicted in cosmic ray environments.

Abstract The European Space Agency’s Gaia spacecraft was launched in 2013 and has been in operation ever since. It has a focal plane of 106 Charge-Coupled Devices (CCDs) which are of the CCD91-72 variant, custom designed by Teledyne e2v. The detectors have been making measurements of parallaxes, positions, velocities, and other physical properties of over one billion stars and other astronomical objects in the Milky Way. Whilst operating in space, CCDs undergo non-ionizing displacement damage from incoming radiation. This causes radiation induced trap defects to form in the silicon lattice which can trap electrons during readout and increase the charge transfer inefficiency (CTI) of the devices significantly. From analysis of in-flight charge calibration data, Gaia’s CTI values have been measured to be lower than what was expected based on the on-ground pre-flight tests. In this study, the CTI and trap landscape in both in-flight and irradiated on-ground devices are modelled to fit the new datasets. This was done thanks to the help of a detector simulation toolkit called Pyxel which implemented a version of a CTI model developed for Gaia called the Charge Distortion Model (CDM). These results provide more insights into the nature of radiation damage and the resulting trap landscapes, both in space and from on-ground irradiations.

AbstractPerovskite photovoltaics have been shown to recover, or heal, after radiation damage. Here, we deconvolve the effects of radiation based on different energy loss mechanisms from incident protons which induce defects or can promote efficiency recovery. We design a dual dose experiment first exposing devices to low-energy protons efficient in creating atomic displacements. Devices are then irradiated with high-energy protons that interact differently. Correlated with modeling, high-energy protons (with increased ionizing energy loss component) effectively anneal the initial radiation damage, and recover the device efficiency, thus directly detailing the different interactions of irradiation. We relate these differences to the energy loss (ionization or non-ionization) using simulation. Dual dose experiments provide insight into understanding the radiation response of perovskite solar cells and highlight that radiation-matter interactions in soft lattice materials are distinct from conventional semiconductors. These results present electronic ionization as a unique handle to remedying defects and trap states in perovskites.

Le Grand collisionneur de hadrons (LHC), le plus grand et le plus puissant au monde, a démarré en 2008 et constitue la dernière étape du complexe des accélérateurs du CERN. Le LHC consiste en un anneau de 27 kilomètres d'aimants supraconducteurs permettant d'accélérer deux faisceaux jusqu'à 7 TeV avant de les faire entrer en collision à 14 TeV dans l'une des cinq expériences de contrôle du résultat de la collision. Le LHC a notamment permis la découverte du boson de Higgs et d'autres particules baryoniques prédites par le modèle standard. L'environnement de rayonnement du LHC et de ses lignes d'injection est composé de différentes particules sur un large spectre d'énergies, du niveau GeV jusqu'au niveau meV (par exemple le neutron thermique). L'équipement électronique fonctionnant dans un environnement de rayonnement aussi rude, principalement basé sur des composants commerciaux prêts à l'emploi (COTS), peut subir des défaillances induites par des effets de rayonnement. La criticité de l'équipement peut être très élevée, dans le meilleur des cas, la défaillance d'un système de contrôle peut conduire à une chute du faisceau, ce qui peut drastiquement rendre le faisceau disponible pour la science et dans le pire des cas, la défaillance d'un système de sécurité peut conduire à la destruction d'une partie de la machine. La nouvelle mise à niveau du LHC prévue pour 2025, le LHC à haute luminosité (HL-LHC) atteindra une luminosité annuelle cinq fois supérieure à celle de la version actuelle du LHC. Par conséquent, les niveaux de rayonnement générés par le fonctionnement de la machine vont également augmenter considérablement. Avec des niveaux de rayonnement aussi élevés, un nombre important de systèmes commerciaux seront exposés à des niveaux de rayonnement auxquels ils ne peuvent résister. Cela impliquera soit de concevoir des systèmes plus robustes et tolérants à base de COTS, soit de remplacer préventivement les systèmes avant leur fin de vie utile. Ainsi, alors qu'au cours des années précédentes, les effets singuliers (EEI) étaient la principale cause de défaillance, à l'avenir, l'effet cumulatif du rayonnement deviendra également une préoccupation majeure. Bien qu'un effort considérable ait été fait dans le passé sur le processus de qualification contre les défaillances induites par les SEE, le processus de qualification pour les effets cumulatifs du rayonnement est resté pratiquement inchangé. L'objectif de ces travaux était donc d'étudier comment la Radiation Hardness Assurance (RHA) du CERN pourrait être améliorée pour répondre à ce nouveau défi et s'assurer qu'aucune défaillance de système n'aura d'impact sur les opérations du LHC. Plusieurs activités ont été menées à cet effet : (i) l'étude des particularités de l'environnement radiatif du LHC et de son impact sur les composants et les systèmes qui y sont exposés, (ii) l'étude de l'adéquation des méthodes de qualification actuelles et le développement d'approches adaptées aux besoins du CERN et (iii) l'étude des méthodes fiables pour estimer la durée de vie des systèmes
The Large Hadron Collider (LHC), the largest and most powerful in the world, started in 2008 and is the last stage of CERN's accelerator complex. The LHC consists in a 27-kilometer ring of superconducting magnets allowing to accelerate two beams up to 7 TeV before colliding them at 14 TeV in one of the five experiments monitoring the result of the collision. The LHC allowed notably the discovery of the Higgs boson and other baryonic particles predicted by the standard model. The radiation environment of the LHC and its injection lines is composed of different particles over a large spectrum of energies, from GeV level down to meV level (e.g. thermal neutron). The electronic equipment operating in such a harsh radiation environment, mostly based on Commercial Off The Shelf (COTS) components, can experience failures induced by radiation effects. The criticality of the equipment can be very high, in the best case, the failure of a control system can lead to a beam dump, which can drastically the availability of the beam for science and in the worst case, the failure of a safety system can lead to the destruction of part of the machine. The new upgrade of the LHC planned for 2025, the High Luminosity LHC (HL-LHC) will achieve an annual luminosity five time higher than the current version of the LHC. Consequently, the levels of the radiation generated by the operation of the machine will also drastically increase. With such high radiation levels, a significant number of COTS-based systems will be exposed to radiation levels they cannot withstand. This will imply to either design more robust tolerant COTS-based systems and/or substitute preventively systems before their end of life. Thus, while in the previous years the Single Event Effects (SEEs) where the dominant cause of failure, in the future, cumulative radiation effect will as well become a major preoccupation. While a huge effort has been done in the past on the qualification process against SEE-induced failures, the qualification process for cumulative radiation effects, remained mostly unchanged. The aim of this work was, therefore, to investigate how the CERN’s Radiation Hardness Assurance (RHA) could be improved to respond to this new challenge and ensure that no system failures will impact the LHC operations. This involved several activities; (i) the study of the particularities of the LHC radiative environment and its impact on the components and systems exposed to it, (ii) the study of the suitability of current qualification methods and the development of approaches adapted to CERN’s needs and (iii) the study of reliable system lifetime estimation methods

Programmée pour 2035, la mission LISA (Laser Interferometer Space Antenna), pilotée par l'Agence spatiale européenne (ESA), marquera une première en devenant le premier détecteur spatial d'ondes gravitationnelles. Opérant dans la gamme des basses fréquences de 0,1 mHz à 1 Hz inaccessible aux détecteurs terrestres, LISA ouvrira une nouvelle fenêtre sur notre univers et une nouvelle ère dans l'étude de la cosmologie. Le design de LISA présente trois vaisseaux formant un triangle équilatéral de 2,5 millions de km de côté, suivant la Terre dans son orbite autour du Soleil. Au cœur du fonctionnement de LISA se trouvent des interféromètres laser de haute précision, détectant des fluctuations de distance de l'ordre d'une dizaine de picomètres entre deux tests masses en chute libre positionnées dans chaque vaisseau. Le cœur de la mesure réside dans ses photorécepteurs à quadrants (QPR), essentiels pour l'enregistrement des signaux interférométriques. Ces QPR se composent d'une photodiode à quadrant (QPD) In0.53Ga0.47As de large surface et à faible capacité couplée à un trans-amplificateurs (TIA) à faible bruit, le tout assemblé dans un boîtier mécanique. Au cours de sa durée de vie de 12,5 ans, LISA sera confrontée à divers types de rayonnements, principalement en provenance du soleil. Un tel rayonnement peut dégrader les QPDs en induisant des défauts cristallins, modifiant les propriétés électroniques du semi-conducteur et donc altérant les performances des QPDs.L'objectif de cette thèse était d'étudier l'impact de l'environnement radiatif spatial sur les principaux paramètres électro-optiques des QPD InGaAs ainsi que leurs répercussions sur les performances des QPR et, par extension, sur les mesures interférométriques de LISA. Les appareils ont été fournis par les membres du groupe de travail sur les QPR du consortium LISA, à savoir les Pays-Bas et le Japon pour les QPD, et l'Allemagne pour les TIA.Dans ce contexte, j'ai développé et calibré cinq montages expérimentaux, permettant d'évaluer les principaux paramètres électro-optiques des QPD comme le courant d'obscurité, la capacité et l'efficacité quantique ainsi que les paramètres globaux du QPR comme le bruit de courant équivalent d'entrée et les réponses en phase et en amplitude face à des signaux interférométriques équivalents à ceux utilisées dans LISA. J'ai également développé des routines Phyton, permettant une procédure d'analyse automatique des données expérimentales. Ces développements expérimentaux et programmes ont permis d'évaluer les paramètres des QPD et QPR, avant et après trois campagnes d'irradiation, utilisant respectivement des protons (20 et 60 MeV, 1x10+9 jusqu'à 1x10+12 p/cm²), gamma (1 à 237 krad) et des électrons (0,5 et 1 MeV). Les conditions d'irradiation maximales dépassaient environ 5 fois les exigences pour LISA. J'ai directement participé aux campagnes d'irradiation, en collaboration étroite avec les équipes techniques du Centre de Protonthérapie Antoine Lacassagne de Nice pour l'irradiation des protons et de l'ONERA de Toulouse pour les irradiations des rayons gamma et des électrons). Les résultats ont démontré la robustesse de ces nouveaux dispositifs face aux radiations, sans aucune défaillance critique observée et avec presque toutes les QPDs répondant aux exigences de LISA. J'ai comparé le facteur de dommage aux résultats existants dans la littérature et exploré comment les caractéristiques intrinsèques des QPDs, telles que le niveau de dopage et la tension de polarisation, influencent leur vulnérabilité faces aux radiations. Un lien fut établi entre la dégradation globale du système, manifestée par une augmentation des niveaux de bruit du QPR et une réduction de la réponse en amplitude, avec la détérioration des paramètres des QPD. Cette corrélation permet d'estimer l'impact des QPD irradiées sur le fonctionnement du QPR et, par extension, sur la mesure de LISA
Scheduled for 2035, the Laser Interferometer Space Antenna (LISA), led by the European Space Agency (ESA), represents a pioneering effort as the first space-based gravitational wave detector. Operating in the low-frequency range of 0.1 mHz to 1 Hz beyond the capabilities of terrestrial detectors, LISA will open a new window to our universe and a new era in cosmological studies. The mission's design features three spacecraft, arranged in an equilateral triangle with each side spanning 2.5 million km, trailing the Earth in its orbit around the Sun. Central to LISA's function are its high-precision laser interferometers, which detect distance fluctuations between test masses in free fall within each spacecraft, with sensitivity to changes as subtle as a dozen picometers. The heart of LISA's detection technology lies in its Quadrants Photoreceivers (QPRs), critical for recording interferometric signals. These QPRs incorporate large area and low capacitance In0.53Ga0.47As Quadrant Photodiodes (QPDs) connected to low noise trans-impedance amplifiers (TIA), everything within a mechanical enclosure. Over its projected 12.5-year lifespan, LISA will encounter diverse radiation types, predominantly from solar emissions. Such radiation can degrade the QPDs by inducing crystal defects that alter the semiconductor properties, impairing the devices' performance.The objective of this thesis was to study the impact of the space radiation environment on the InGaAs QPDs' main electro-optical parameters. This investigation was further extended to assess the consequential implications of such degradations on the QPR performances and by extension to the LISA interferometric measurements. The devices have been provided by the members of the LISA Consortium Quadrant Photoreceivers Working Group, namely the QPDs from NL and Japan, and TIA FEE from Germany.In this context, I have developed and calibrated five experimental set-ups, allowing to evaluate the main QPDs' parameters like dark current, capacitance, and quantum efficiency and the overall QPR parameters like input equivalent current noise and phase and amplitude responses to interferometric LISA-like signals. I have also developed Phyton routines, allowing an automatic analysis procedure of the experimental data. I have used these experimental and software developments to evaluate the QPD and the QPR parameters, before and after three irradiation types, using respectively protons (20 and 60 MeV, 1x10+9 up to 1x10+12 p/cm^2), gamma (1 to 237 krad) and electrons (0.5 and 1 MeV). The maximum irradiation values exceeded ~5 times LISA requirements. I have directly participated to the irradiation campaigns, collaborating closely with technical teams from Antoine Lacassagne Proton-Therapy Center in Nice for protons irradiation and ONERA in Toulouse for gamma rays and electrons irradiations).The findings demonstrated the new devices' robust radiation tolerance, with no critical failures observed and almost all QPDs meeting LISA's requirements even post-irradiation. I compared our measured damage factor to those of the literature and explored how the intrinsic characteristics of QPDs, such as doping level and bias voltage, influence their vulnerability to radiation damage. Finally, I established a clear connection between the overall system's degradation manifested through increased noise levels and reduced amplitude response, and the modification of the QPDs' parameters. This correlation shows the ability to predict the impact of radiation-damaged QPDs on the functionality of the QPRs and, by extension, on the accuracy of LISA's gravitational wave measurements