Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

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3D dose distribution measurements for electronic brachytherapy treatments using the INTRABEAM system

Département Métrologie Instrumentation et Information (LIST)

Laboratoire de Métrologie de la Dose

01-06-2021

PsD-DRT-21-0093

christel.stien@gmail.com

Electronic brachytherapy is a cancer treatment technique using low energy X-rays (50 keV) generated by miniaturized X-ray tubes positioned in contact with the tissues to be irradiated. In France, the most widespread system is INTRABEAM provided by Zeiss. A dozen French medical services are equipped and use it mainly to treat breast cancer. Despite the advantages of electronic brachytherapy, its use is currently limited by the fact that each system has its own calibration method in terms of absorbed dose to water, which is not, in most cases, traceable to a national metrology standard. It is therefore necessary to develop and implement a generic and robust calibration methodology, as well as suitable measurement procedures for the quality control and verification of the treatment planning systems for electronic brachytherapy treatments. The LNHB, which is the French metrology laboratory for ionizing radiation, is involved in the European metrology project 18NRM02 PRISM-eBT ?Primary standards and traceable measurement methods for X-ray emitting electronic brachytherapy devices? which aims at providing solutions in this direction. The proposed subject fits into the context of this project. The objective of the proposed work is to measure the distributions of absorbed dose in water in 3 dimensions around the INTRABEAM source equipped with its spherical applicator dedicated to breast cancer treatments. For this, dosimetric gels will be used. They consist in radiosensitive gels, which can be read either by Magnetic Resonance Imaging (MRI) or by optical tomography.

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Accountability analysis of consensus algorithms for innovative blockchain applications

Département Ingénierie Logiciels et Systèmes (LIST)

Laboratoire exigences et conformité des systèmes

01-06-2021

PsD-DRT-21-0095

arnault.lapitre@cea.fr

New usages based on the disintermediation of exchanges are becoming increasingly important in a digital world that is more and more extensive, globalized and open. These usages are made possible by the existence of "decentralized trust" mechanisms called distributed registries (DLT), of which blockchain is the best known representative. However, the technologies involved in these mechanisms are still immature and suffer from limitations that slow down their adoption: considerable ecological impact, slowness, approximate implementations of the algorithms and security proofs provided, uncertainties about the capacity to scale up and to guarantee its resilience (meaning the reconfiguration of the system when some of its entities behave maliciously). Overcoming these shortcomings is a crucial challenge to address the economic, societal and environmental issues of tomorrow's digital world and could lead to the widespread adoption of these technologies. In this context, an innovative approach to establish ?proof of stake?-based consensus is to monitor the behavior of participants with respect to, first, the consensus protocol, second, an arbitrary applicative protocol, with participants expected to follow both, and then establishing proof of compliant or non-compliant behavior, even in the presence of Byzantine actors.

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Polar codes for fault tolerant quantum computation

Département Systèmes (LETI)

Laboratoire Sans fils Haut Débit

01-10-2021

PsD-DRT-21-0103

valentin.savin@cea.fr

The last years have seen significant advances in the field of quantum technologies, promising a disruptive impact in information and computing technologies. Nonetheless, for unleashing the full computational power that quantum computers can bring, a critical task is to protect the quantum computation from the inherent quantum noise. This makes quantum error correction (QEC) an essential component of any quantum computer, acting as an interface between physical (noisy) and logical (noiseless) qubits. This project aims at exploring pioneering approaches to fault-tolerant (FT) quantum computation, relying on quantum polar codes. Introduced first in 2009 for classical systems, and then generalized to the quantum case, polar codes arguably represent the most important advance in coding theory of the past decade. They achieve the coherent information (one-shot capacity) of any quantum channel, and come equipped with an efficient decoding algorithm, whose complexity scales log-linearly with the code length. Yet, despite their excellent error correction properties, polar codes have been hardly explored for quantum computing. The main objective of this project is to develop a complete framework of FT quantum computation using quantum polar codes, thus harnessing their unique benefits in terms of error correction capacity, decoding, and structure.

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Life Cycle Assesment of Li-ion and post-Li-ion batteries

Département de l'Electricité et de l'Hydrogène pour les Transports (LITEN)

Laboratoire Matériaux

01-09-2021

PsD-DRT-21-0105

fabien.perdu@cea.fr

The post-doc will realize environmental analyses, such as, but not only, Life Cycle Analysis, of existing battereis, or batteries being developed. This includes modeling the production steps, including chemical synthesis processes. The modelingca n stop at the level of a cell, or sometimes include the pack level and recycling. The candidate must master Life Cycle Assesment and associated software and databases. He or she must be able to have a critical eye on available data, on bibliography, to analyse the results, and to draw conclusions in terms of path for improvement. He or she must also have a chemical background to correctly model these key steps in the production and recycling of the batteries. The candidate must be proactive, autonomous, while being able to work in a team and prone to sharing results and knowledge.

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Post-doctoral position in AI safety and assurance at CEA LIST

Département Ingénierie Logiciels et Systèmes (LIST)

Labo.conception des systèmes embarqués et autonomes

01-10-2020

PsD-DRT-20-0110

morayo.adedjouma@cea.fr

The position is related to safety assessment and assurance of AI (Artificial Intelligence)-based systems that used machine-learning components during operation time for performing autonomy functions. Currently, for non-AI system, the safety is assessed prior to the system deployment and the safety assessment results are compiled into a safety case that remains valid through system life. For novel systems integrating AI components, particularly the self-learners systems, such engineering and assurance approach are not applicable as the system can exhibit new behavior in front of unknown situations during operation. The goal of the postdoc will be to define an engineering approach to perform accurate safety assessment of AI systems. A second objective is to define assurance case artefacts (claims, evidences, etc.) to obtain & preserve justified confidence in the safety of the system through its lifetime, particularly for AI system with operational learning. The approach will be implemented in an open-source framework that it will be evaluated on industry-relevant applications. The position holder will join a research and development team in a highly stimulating environment with unique opportunities to develop a strong technical and research portfolio. He will be required to collaborate with LSEA academic & industry partners, to contribute and manage national & EU projects, to prepare and submit scientific material for publication, to provide guidance to PhD students.

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New Al(Ga)N templates for optimized epitaxial growth of UV LEDs

Département des Plateformes Technologiques (LETI)

Laboratoire

01-01-2021

PsD-DRT-20-0113

guillaume.rodriguez@cea.fr

UV-C LEDS are to replace Hg based UV-lamps for applications related to air and water sterilization and decontamination , a subject of importance in the present day health context. However, UV-C LEDs, which rely on the use of AlGaN nitride alloy epitaxial layers, are still not efficient enough to be considered as a possible alternative on a large industrial scale. This is so for different reasons, related to the quality of the nitride material and/or to the technology employed for fabricating the diodes. We have created an academic consortium which, around LETI, can address the different issues at stake, in order to develop a true technology stream in this field. One of the issue concerns the structural quality of the epitaxial layers, dislocations being non-radiative defects that kill the internal efficiency of the LED. Within the consortium, we are in charge of developping new and optimized template layers, i.e. the epitaxial layer nucleated on the surface of the sapphire substrate, since an important part of the defects in the LEDs arise from this nucleation layer. To address this point, we will develop new and original methods for the deposition of AlN and AlGaN templates: reactive sputtering, co-sputtering (for alloy templates) and Pulsed laser Deposition (PLD). The layers will be characterized on the Nano-Characterization Platfom of LETI and will be evaluated according to the electro-optical properties of the LEDs structures that will be grown by epitaxy on top of these templates.

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