Enhancing the sensitivity of magnetic sensors by 3D metamaterial shells

Magnetic sensors are key elements in our interconnected smart society. Their sensitivity becomes essential for many applications in fields such as biomedicine, computer memories, geophysics, or space exploration. Here we present a universal way of increasing the sensitivity of magnetic sensors by surrounding them with a spherical metamaterial shell with specially designed anisotropic magnetic properties. We analytically demonstrate that the magnetic field in the sensing area is enhanced by our metamaterial shell by a known factor that depends on the shell radii ratio. When the applied field is non-uniform, as for dipolar magnetic field sources, field gradient is increased as well. A proof-of-concept experimental realization confirms the theoretical predictions. The metamaterial shell is also shown to concentrate time-dependent magnetic fields upto frequencies of 100 kHz

Detecting dependencies in Enterprise JavaBeans with SQuAVisiT

We present recent extensions to SQuAVisiT, Software Quality Assessment and Visualization Toolset. While SQuAVisiT has been designed with traditional software and traditional caller-callee dependencies in mind, recent popularity of Enterprise JavaBeans (EJB) required extensions that enable analysis of additional forms of dependencies: EJB dependency injections, object-relational (persistence) mappings and Web service mappings. In this paper we discuss the implementation of these extensions in SQuAVisiT and the application of SQuAVisiT to an open-source software system. Keywords: Java, Visualization, Containers, Web services, Open source software, Computer architectur

Microfabricated test structures for thermal gas sensor

International audienceMicrofabricated test structures are presented for the proof validation of a new chemical sensor concept. The proposed detection principle is based on time constant shift of a thermal device covered with zeolites when target species are adsorbed. © 2016 IEEE

Shielded Electron Microprobe and some of its main applications in HotlabsCharacterization of MOX irradiated fuels treated at very high temperatures

International audienceThanks to its precision, its reproducibility and its stability, Electron Microprobe is a well suited technique for accurately analyzing nearly all chemical elements at concentration levels down to few 10’s ppm with a spatial resolution of about 1 µm, which is relevant to microstructures in a wide variety of materials and mineral specimens. For irradiated samples, EPMA is also one of the technique of choices and can support nuclear fuel development, control, metallurgical or glass analysis. It reveals fine compositional details and the distribution of main and trace elements across the surface of the sample.CAMECA leader in scientific instruments has been manufacturing Electron Microprobe (EPMA) since 1958 and will present its latest CAMECA shielded EPMA model, SKAPHIA released in 2016 for hotlab facilities. One example of the LECA/STAR shielded EPMA in hotlab handling nuclear fuel will be highlighted. In this example, the microstructure and chemical evolution of fuel pellets submitted to two different nuclear severe accident scenarii are shown. EPMA helped to highlight the impact of the atmosphere (i.e the oxygen potential) on the behavior of the fuel and fission products during these tests. These studies are of particular importance to evaluate and better predict the consequences of such an accident in term of contamination

Radiation protection of workers associated with secondary neutrons produced by medical linear accelerators

This paper presents a measurement campaign carried out in six medical electron linear accelerator facilities to evaluate occupational exposure associated with photons and secondary neutrons for several encountered configurations. No strong correlation between dose and configuration has been observed. Assuming realistic hypotheses, the annual effective dose to staff due to external exposure has been estimated to 0.9 mSv, 54% associated with the decay of activation products and 7% due to exposure to leakage neutrons. © 2008 Elsevier Ltd. All rights reserved

Self-identification algorithm for zeolite-based thermal capacity gas sensor

International audienceWe demonstrate a new operation mode of thermal gas sensor based on thermal capacity extraction with identification algorithm. The system is a silicon microstructure covered with zeolites operated at constant temperature while stimulated by heat pseudo-random sequence. The proposed detection principle is demonstrated at room temperature and atmospheric pressure through the detection of gas water molecules with an hydrophilic FAU-type zeolite coating. The identification algorithm is a continuous-time closed-loop identification algorithm based on the instrumental variable principle

Self-identification algorithm for zeolite-based thermal capacity gas sensor

International audienceWe demonstrate a new operation mode of thermal gas sensor based on thermal capacity extraction with identification algorithm. The system is a silicon microstructure covered with zeolites operated at constant temperature while stimulated by heat pseudo-random sequence. The proposed detection principle is demonstrated at room temperature and atmospheric pressure through the detection of gas water molecules with an hydrophilic FAU-type zeolite coating. The identification algorithm is a continuous-time closed-loop identification algorithm based on the instrumental variable principle