Development of new spectrometric methods for the characterization of uranium-bearing ore
This subject aims at developing new methods of X/gamma-ray spectrum analysis for the characterization of uranium-bearing ore, enabling to process data obtained in the framework of nuclear mining activities. This subject will be developped into two parts. The first part will concern the processing of complex gamma-ray spectra, obtained using different types of medium-resolution scintillators (such as NaI or LaBr3 detector). The main purpose of this part will be related to the processing of complex regions of interest using deconvolving methods by non-parametric Bayesian inference, notably by using the SINBAD code, initially developed by CEA LIST for the processing of HPGe spectra. The second part of the subject will concern the analysis of low-resolution spectra obtained using a NaI detector in order to obtain a spectrometric information. In this case, a traditional approach based on the analysis of photoelectric peaks is not conceivable. The problem will be studied in the form of an inverse problem using a model of the detector response and a reconstruction, using an approach analogous to computed tomography. The performances of different types of reconstruction algorithms will be studied (EM analysis, non-parametric Bayesian approach).
Planning energy consumption within an eco-district
Energy consumption and production are changing, and the birth of eco-districts is now a reality which is a continuation of these changes. Eco-districts consists in grouping within the same territory entities which consume or produce energy and in managing these resources locally.
Alongside these developments, homes, shops and even offices are increasingly equipped with communicating sensors and intelligent devices that can be controlled remotely. It is therefore possible to control these devices taking into account several factors: the financial or environmental cost of energy consumed, the respect of comfort desired by the people and the intent of the directors of the eco-district. Many algorithms have been developed in order to plan and control devices more or less autonomous, while expert systems have often been excluded because of their lack of expressiveness in this area. The goal of this postdoctoral fellowship is to check if fuzzy expert systems can be used to plan devices which consume a source of energy.
Development of an hermetic thin flim packaging for RF MEMS switches
Leti has developed for many years a RF MEMS switch process which have demonstrated RF performances at the state-of-the-art as well as a process maturity level closed to industrial standards. To finalize its component and especially to ensure long-terms reliability level for space applications, Leti is today developing an innovative hermetic thin film packaging process.
The applicant will join a project team working on the development of this new technological brick. In a first step, the applicant will be in charge of the design of the process test vehicles, of the follow-up of their silicon batches fabrication in clean room and of their characterization during the process. In a second step, the applicant will perform a modeling study to optimize the design of the switches integrating this new packaging. In particular, he will propose new designs for mid RF power applications. Finally, the applicant will be in charge of the follow-up of the realization of silicon batches for the RF MEMS switches demonstrators. He will then supervise and participate to all the characterization studies on packaged components.
Development of a solid electrolyte to optimise lithium microbatteries
All-solid-state microbatteries are developing for nomad applications (RFID, autonomous sensors…). Their main advantages are due to the electrolyte, a thin film inorganic material allowing a very good cyclability (>10000 cycles), long life, good thermal resistivity and excellent safety. These thin film microbatteries have to response to a challenge of integration: decreasing of size but increasing of performances.
The goal of this post-doc is to develop the electrolyte performances. The first part will focus on the optimisation of the actual electrolyte and the second part on the development of a new electrolyte material. The electrolyte deposition will be done by Physical Vapor Deposition.
Le position is in the CEA/LITEN/DTNM/LCMS for a common laboratory CEA/ST Microelectronics.
Outgassing studies for advanced lithography
This work address a "post doc" person. The frame work of this subject is a advanced lithography multifaisceaux Ebeam development project. Within this project framework, an multiEbeam tool is developed in a international partnership context.
Strong contamination constraints of the projection optic are identified due to resists outgassing during theirs activations by electronic expositions. Layers contamination due to resists outgassing will be studied. The candidate will be in charge to carry out outgassing studies on various resist samples in support to the existing team and using Leti outgassing studies tool and characterization tools available on Leti (BEM, XPS, interferometer,...).
Candidate will implement methodologies already developed in Leti (pumping speed, outgassed elements identification,...) and will make contribution to improvement all of these methods. It will also supervise realization of objects useful for outgassing studies(Ebeam projection optics simulator) which will be carried on Leti. The candidate will carry out electron beam characterization on the outgassing tool and could be force of proposal for improvement. He will also take charges characterization of contaminants layers. The candidate will evolved in advanced lithography context and will be in close collaboration with international teams. English is needed.
Micro-energy sources for biomedical applications
There is a growing interest towards wireless implantable systems for in vivo biomedical applications. However, such implantable systems have a limited lifetime determined by the battery capacity. CEA LITEN is working on innovative miniaturized systems integrating an energy harvesting component with a rechargeable battery. This type of micro-systems will be used for powering sensors or other implantable medical devices. The post-doctoral researcher will work on the design, the fabrication and the characterization of demonstrators consisting of the energy harvesting component, the battery and a power management circuit. Numerical simulations could also be performed, with the help of specialized engineers. The characterization of the demonstrators and the numerical simulation results will allow the post-doctoral researcher to propose innovative solutions for optimizing the system. The post-doctoral researcher will work in a multi-disciplinary team, which requires strong abilities for team working and communication.
Automatic generation of dynamic code generators from legacy code
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Our laboratory is developing a technology for dynamic code generation around a tool called deGoal. deGoal is a tool designed to build specialized code generators (also known as compilettes) customized for each computing kernel we want to accelerate in an application. Such compilettes are designed with the aim to perform data- and architecture-dependent code optimizations and code generation at runtime. Furthermore, compilettes provide very fast code generation and low memory footprint. This approach is fundamentally different from the standard approach for dynamic compilation as used for example in Java Virtual Machines.
In order to target computing architectures that include domain-specific accelerators and to raise the level of abstraction of the source code of compilettes, deGoal uses a dedicated language. This language provides the best performance we can achieve from our technology, and has demonstrated its ability to achieve good performance improvements compared to highly optimised static code. However, the drawback is that one needs to rewrite the source code of a computing kernel from scratch in order to build a new compilette.
Goal
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The goal of this PostDoc is to implement an automatic generator of compilettes able to work from existing source code (typically: ANSI C), and able to be integrated in an industry-grade code generation toolchain.
Design of a new generation of MEMS flow or viscosity sensors
This Post-doc is defined to answer to various industrial requests for flow sensors and viscosity sensors working on a large range, low cost and able to measure different kind of fluids (liquid or gas).
The objective of this post-doc is to consider the design of a new generation of MEMS sensor for measuring flow or viscosity of any fluid that meets the specifications provided by the industry.
In particular, the possibilities of using a 3-axis micro-force sensor developed in the laboratory will be explored by exploiting the drag force or the tangential stresses near the walls of the pipes. Different cases will have to be evaluated depending on the flow dynamics of the different fluids.
A modeling and sizing of the sensor will have to be developed to determine the interactions with the fluids and the characteristics of the forces in the different flow rates.
The candidate should possess strong knowledge on fluidic and microsystems.
Compressed Sensing for ultrasonic imaging: disruptive method development and prototyping
In non-destructive ultrasonic testing, multi-element sensors are used for the inspection of structures to ensure the safety of people and infrastructures. Currently, one of the driving factor of an ultrasonic method is the number of elements of the sensor, influencing the speed and efficiency of the inspection but also the cost and the volume of the equipment. This project aims at developing a prototype of a multi-element sensor with a limited number of elements compared to current state of the art equipment, without losing imaging resolution. To achieve this goal, Compressed Sensing (CS), a recent technique of signal processing allowing to go beyond the traditional sampling theorems and to reconstruct data from severely undersampled measurements, will be used. The ultrasonic inspection procedure will need to be entirely rethought to meet the CS requirements, specifically the sparsity of the measured data and the incoherence of the measurement process. The expected results is a significant reduction (of the order of 5) of the number of elements to conduct imaging, which would be a true revolution in NDT with direct applications in various industrials sectors.
The following laboratories, all located in Saclay (France) of the CEA (the French atomic commission), will participate to the project: the NDT department for its expertise in multi-element ultrasonic testing and Neurospin and Cosmostat for their expertises in the field of CS, mainly applied to medical RMI imaging and astrophysics, respectively. The collaboration between these three labs, each among the worldwide leading institutes in their respective fields, will ensure the creation of a new and disruptive family of sensors.
Study and evaluation of a micro resonator based thermal sensor for uncooled infrared imagery
The project aims at establishing the feasibility of a novel infrared microbolometer sensor exploiting the thermal sensitivity of a free oscillating micro-nano-mechanical system (M & NEMS), whose resonant frequency changes with the infrared flux it absorbs. This is a concept out who was the subject of three patents.
The project addresses the needs of high resolution uncooled infrared imaging sensors (spectral band ranging from 8µm to 12µm) which is presently in expansion but whose next generation of products is still waiting for a breakthrough to reduce the pixel size, a key factor to improve performance and reduce the cost.
The objective of this post doctoral study is to achieve a proof of concept of this new architecture. In this outlook, the study will cover first the sizing of the device, then its design, implementation and validation at a single pixel level.