J.L. Leray

Cea Leti, Grenoble, Rhône-Alpes, France

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Publications (109)144.25 Total impact

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    ABSTRACT: This paper investigates the TID sensitivity of silicon-based technologies at several MGy irradiation doses to evaluate their potential for high TID-hardened circuits. Such circuits will be used in several specific applications suc as safety systems of current or future nuclear power plants considering various radiation environments including normal and accidental operating conditions, high energy physics instruments, fusion experiments or deep space missions. Various device designs implemented in well established bulk silicon and Partially Depleted SOI technologies are studied here up to 3 MGy. Furthermore, new insights are given on the vulnerability of more advanced technologies including planar Fully Depleted SOI and multiple-gate SOI transistors at such high dose. Potential of tested technologies are compared and discussed for stand-alone integrated circuits.
    IEEE Transactions on Nuclear Science 08/2013; 60(4):2590-2597. DOI:10.1109/TNS.2013.2249095 · 1.46 Impact Factor
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    ABSTRACT: In this paper we perform exploratory study of short pulses of 14 MeV neutron obtained by laser inertial confinement fusion. We focus on the neutron Radiation-Induced Conductivity (n-RIC) and we show similarities and differences with the classical RIC obtained from photon or charged particles (electron) beams. The n-RIC responses of two insulating linear polymers is experimentally compared: polyethylene (CH2)n and polytetrafluoroethylene (CF2)n.
    2013 3rd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications (ANIMMA); 06/2013
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    ABSTRACT: This paper investigates the vulnerability of several micro- and nano-electronic technologies to a mixed harsh environment including high total ionizing dose at MGy levels and high temperature. Such operating conditions have been revealed recently for several applications like new security systems in existing or future nuclear power plants, fusion experiments, or deep space missions. In this work, the competing effects already reported in literature of ionizing radiations and temperature are characterized in elementary devices made of MOS transistors from several technologies. First, devices are irradiated using a radiation laboratory X-ray source up to MGy dose levels at room temperature. Devices are grounded during irradiation to simulate a circuit which waits for a wake up signal, representing most of the lifetime of an integrated circuit operating in a harsh environment. Devices are then annealed at several temperatures to discuss the post-irradiation behavior and to determine whether an elevated temperature is an issue or not for circuit function in mixed harsh environments.
    2013 3rd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications (ANIMMA); 06/2013
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    ABSTRACT: Inertial Confinement Fusion (ICF) experiments performed on high-power laser facilities produce a high intensity short pulse of 14 MeV neutrons. The interaction of such an environment with coaxial cables widely used for signals transmission of diagnostic equipments induces parasitic transient currents. Depending on the magnitude and shape of those currents, measurement signals are likely to be altered and electric devices might be damaged. This paper reviews our knowledge about the generation of parasitic current in polyethylene (PE), PolyTetraFluorEthylene (PTFE) and PolyEtherEtherKetone (PEEK) insulators subjected to an ICF neutron pulse. It provides a clear evidence of the existence of a prompt neutron component and a very fast, nanosecond delayed radiation induced electromotive force (RIEMF) in insulator response to very short neutron pulses.
    IEEE Transactions on Nuclear Science 08/2012; 59(4-4):1289-1295. DOI:10.1109/ANIMMA.2011.6172855 · 1.46 Impact Factor
  • D. Herve, Ph. Paillet, J. L. Leray
    MRS Online Proceeding Library 01/2011; 284. DOI:10.1557/PROC-284-287
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    ABSTRACT: The implementation of equipments with embedded electronic to monitor, control, measure and operate future large facilities dedicated to high energy physics or nuclear fusion are necessary. Reliable operation of these equipments will be achieved through availability and reliability analysis. In several cases, the equipment selection or development approach has to be done by considering a harsh environment in terms of radiations. In order to implement these systems in such environments shielding, location and distance from the source must be considered to reduce, to protect and to avoid radiation effects. People in charge of the choice of the equipments have to take into account and mitigate radiation effects from subsystem to system level. This requires an approach integrating tradeoff between performance and reliability, between the use of the state of the art of technologies and robust and well known devices. Experience and knowledge from previous programs should be considered to build approach and strategy that may be necessary to overcome difficulties. In the present paper, we will review the main challenges faced by designers for systems implementation with embedded electronics in future facilities dedicated to international physics programs.
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    ABSTRACT: To assess phenomena occurring in coaxial cables under high flux of 14 MeV neutrons in D-T fusion experiments, a polyethylene, Teflontrade or vacuum sandwiched between two electrodes mock-up is proposed. This Mock-Up was exposed to the subnanosecond flux at the LLE OMEGA facility in Rochester (above 10<sup>18</sup> n/cm<sup>2</sup>-s) normally to the electrodes or with a tilt angle. A radiation induced current probing a radiation induced electromotive force (RIEMF) is measured and a model is proposed based on the range of the neutron-induced recoils. The GEANT4 simulation toolkit has been used to take advantage of the implementation of both nuclear and electromagnetic processes in order to compute the tracks and the strong angle dependence. Good agreements between simulations and experimental results are found for polyethylene in contrast with Teflontrade where the 3-alpha break-up of <sup>12</sup>C not considered in GEANT4 seems to make a major contribution to the measured induced current. Comparison with the photon flux is made.
    IEEE Transactions on Nuclear Science 01/2009; 55(6-55):3060 - 3069. DOI:10.1109/TNS.2008.2006171 · 1.46 Impact Factor
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    ABSTRACT: The diagnostic designs for the Laser Mégajoule (LMJ) will require components to operate in environments far more severe than those encountered in present facilities. This harsh environment will be induced by fluxes of neutrons, gamma rays, energetic ions, electromagnetic radiations, and, in some cases, debris and shrapnel, at levels several orders of magnitude higher than those experienced today on existing facilities. The lessons learned about the vulnerabilities of present diagnostic parts fielded mainly on OMEGA for many years, have been very useful guide for the design of future LMJ diagnostics. The present and future LMJ diagnostic designs including this vulnerability approach and their main mitigation techniques will be presented together with the main characteristics of the LMJ facility that provide for diagnostic protection.
    Review of Scientific Instruments 10/2008; 79(10):10F301-10F301-8. DOI:10.1063/1.2991161 · 1.58 Impact Factor
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    ABSTRACT: The next generation of large scale fusion devices—ITER/LMJ/NIF—will require diagnostic components to operate in environments far more severe than those encountered in present facilities. This harsh environment is the result of high fluxes of neutrons, gamma rays, energetic ions, electromagnetic radiation, and in some cases, debris and shrapnel, at levels several orders of magnitude higher than those experienced in today’s devices. The similarities and dissimilarities between environmental effects on diagnostic components for the inertial confinement and magnetic confinement fusion fields have been assessed. Areas in which considerable overlap have been identified are optical transmission materials and optical fibers in particular, neutron detection systems and electronics needs. Although both fields extensively use cables in the hostile environment, there is little overlap because the environments and requirements are very different.
    Review of Scientific Instruments 10/2008; 79(10):10F304-10F304-5. DOI:10.1063/1.2972024 · 1.58 Impact Factor
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    IEEE Transactions on Nuclear Science 09/2008; DOI:10.1109/TNS.2008.928567 · 1.46 Impact Factor
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    Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 04/2008; DOI:10.1016/j.nimb.2008.03.219 · 1.19 Impact Factor
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    ABSTRACT: The National Ignition Facility (NIF) and the Laser Megajoule Facility (LMJ) are currently under construction in the U.S. and France, respectively. Ignited targets at these facilities are anticipated to produce up to 10^19 DT neutrons. For approximately 500 ns after ignition, the NIF and LMJ target diagnostics and control systems will work under extremely harsh radiation conditions. In particular, neutron-induced signals in cables can compromise or destroy diagnostic instruments and control systems. Recent results of neutron-induced signal measurements at 30 kJ in different cables at the 60-beam OMEGA Laser Facility will be reported. Based on these results, specific recommendations on cable selection for the NIF and LMJ will be given. Neutron-background mitigation techniques in the NIF neutron time-of-flight diagnostics will be presented. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under the Cooperative Agreement No. DE-FC52-92SF19460.
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    ABSTRACT: We propose a model of currents induced by 14 MeV neutrons in dielectrics, which agrees well with observed data for the first time in the range of large fluxes (above 10<sup>18</sup> n/cm<sup>2</sup>/s). We propose simple analytical model and numerical calculation using Geant4 consistent with experiments done at OMEGA Inertial Confinement Fusion facility.
    Radiation and Its Effects on Components and Systems, 2007. RADECS 2007. 9th European Conference on; 10/2007
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    ABSTRACT: Considering the technology trends of future electronics, panelists have reviewed some of the most demanding applications. These sectors were successively, the new nuclear physics facilities, for knowledge and for energy, and the vital issue of reliability of avionics systems.
    Radiation and Its Effects on Components and Systems, 2007. RADECS 2007. 9th European Conference on; 10/2007
  • J. L. Leray
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    ABSTRACT: Since the 80s it is known that Terrestrial Cosmic Rays, mainly reported as Atmospheric Neutrons, can penetrate the natural shielding of buildings, equipments and circuit package and induce Soft Errors in integrated circuits and breakdown of power devices. The high-energy neutron fluxes of interest range between 10 particles/cm2/h at sea level and some 103 particles/cm2/h at typical airplanes flight altitude of 30,000 feet, with modulation due to Solar Flares. In the 90s the phenomenon has pervaded as a consequence of the roadmap of electronic devices, especially downscaling of design rules, increase of signal bandwidth and increase of the size of DRAM and SRAM memory, standalone or embedded on processors and system-on-chips. Failure-in-time and soft error rate became unacceptable. Test Standards and design solutions have been proposed to maintain reliability of commercial products and improve those used in special such as avionic computers. The paper describes the Atmospheric Neutron flux, the effects in the main classes of devices and specific cases such as neutron-induced single event upset observed in CMOS vs. CMOS/SOI and some mitigation issues. A model called CCPM (critical cross-point model) is proposed to provide critical graphs of technology node sensitivity along the scaling trend of CMOS.
    Microelectronics Reliability 09/2007; DOI:10.1016/j.microrel.2007.07.101 · 1.21 Impact Factor
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    S. Girard, J. Baggio, J.-L. Leray
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    ABSTRACT: Transient radiation-induced effects in air-guiding photonic crystal fibers (Air-PCF) are investigated for the first time to our knowledge. We characterize the vulnerability of this kind of waveguide by measuring the time dependent changes of their radiation-induced attenuation (RIA) at 1.55 μm. We compare their radiation response to those of two silica-based single-mode fibers with germanium-doped and pure-silica cores. An X-ray pulse induces globally the same effects in all waveguides: a strong and transient increase of RIA. For higher tested doses (10<D<100 Gy), Air-PCF exhibits an interesting saturation of RIA at ∼0.1 dB/m. The possible mechanisms involved in this radiation response are discussed. In particular, we assume that the design of the photonic bandgap structure of the fiber, responsible for the light guidance in the air-core, could strongly affect the amplitude of RIA. The kinetics of RIA recovery depends predominantly on the point defects created at the air/silica interface and in the silica-based part of the microstructured cladding.
    IEEE Transactions on Nuclear Science 01/2006; DOI:10.1109/TNS.2005.860735 · 1.46 Impact Factor
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    ABSTRACT: The Laser Megajoule project is a major component of the French simulation program to study nuclear fusion by inertial confinement. The future Laser Megajoule facility requires control-command systems that will operate in a harsh radiative environment. Commercial off-the-shelf optical fiber data links are envisaged as a radiation tolerant solution for this application. In this paper, we present our preliminary study of their vulnerability. For this, we firstly have used an original method consisting of ultraviolet (∼5 eV) exposures of the fibers to identify the different germanosilicate optical fibers containing phosphorus, which leads them unacceptable for both steady state γ-rays and successive pulsed X-ray irradiations. We have demonstrated the validity of the γ-UV comparison by spectroscopic measurements. After this first selection, we have tested under pulsed X-rays (dose rate >10 MGy/s dose <0.5 kGy) the resistance of the P-free optical fibers at 1310 nm for the shortest times after an ionization pulse (10<sup>-9</sup> to 10<sup>-1</sup> s). Based on these results, we discuss the validity of the optical fiber data links for the control-command applications in LMJ facility.
    IEEE Transactions on Nuclear Science 11/2005; DOI:10.1109/TNS.2005.855813 · 1.46 Impact Factor
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    ABSTRACT: Les fibres optiques présentent de nombreux avantages incitant à les intégrer dans des applications devant résister aux environnements radiatifs associés aux domaines civil, spatial ou militaire. Cependant, leur exposition à un rayonnement entraîne la création de défauts ponctuels dans la silice amorphe pure ou dopée qui constitue les différentes parties de la fibre optique. Ces défauts causent, en particulier, une augmentation transitoire de l'atténuation linéique des fibres optiques responsable de la dégradation voire de la perte du signal propagé dans celles-ci. Dans cet article, nous comparons les effets de deux types d'irradiation: une impulsion X et une dose $\gamma $ cumulée. Les effets de ces irradiations sont ensuite comparés avec ceux induits par une insolation ultraviolette (244 nm) sur les propriétés d'absorption des fibres optiques. Nous montrons qu'il existe des similitudes entre ces différentes excitations et qu'il est possible, sous certaines conditions, d'utiliser celles-ci afin d'évaluer la capacité de certaines fibres optiques à fonctionner dans un environnement nucléaire donné.
    Journal de Physique IV (Proceedings) 06/2005; DOI:10.1051/jp4:2005127021 · 0.35 Impact Factor
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    ABSTRACT: In this paper we explore the sensitivity of commercial static random-access memory devices to 14 MeV neutrons. The effects on bulk technologies are investigated as a function of supply voltage and angle of incidence. Monte Carlo simulations of nuclear interactions with device architecture are used for comparison with experimental data. This simulation analysis allows us to determine the key parameters of the device sensitivity as a function of the technology integration.
    IEEE Transactions on Nuclear Science 11/2004; DOI:10.1109/TNS.2004.835073 · 1.46 Impact Factor
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    ABSTRACT: The design of plasma diagnostics for the future MJ class lasers (LMJ–Laser MégaJoule—in France or NIF—National Ignition Faciliy— in the USA) must take into account the large increased radiation field generated at the target and the effect on the diagnostics components. These facilities will focus up to 1.8 MJ ultraviolet laser light energy into a volume of less than 1 cm3 in a few nanoseconds. This very high power focused onto a small target will generate a large amount of x rays, debris, shrapnel, and nuclear particles (neutrons and gamma rays) if the DT fuel capsules ignite. Ignition targets will produce a million more of 14 MeV neutrons (1019 neutrons) by comparison with the present worldwide most powerful laser neutron source facility at OMEGA. Under these harsh environmental conditions the survivability goal of present diagnostic is not clear and many new studies must be carried out to verify which diagnostic measurement techniques, can be maintained, adapted or must be completely changed. Synergies with similar environment studies conducted for magnetic fusion diagnostic design for ITER facility are considered and must be enhanced.
    Review of Scientific Instruments 10/2004; 75(10):4204-4212. DOI:10.1063/1.1789610 · 1.58 Impact Factor

Publication Stats

1k Citations
144.25 Total Impact Points


  • 1989–2009
    • Cea Leti
      Grenoble, Rhône-Alpes, France
  • 1994–2007
    • Institute of Geophysics, China Earthquake Administration
      Peping, Beijing, China
  • 1998
    • CERN
      Genève, Geneva, Switzerland
  • 1997
    • University of Milan
      Milano, Lombardy, Italy
  • 1996
    • Soitec
      Bernin, Rhône-Alpes, France
  • 1992–1996
    • France Télécom
      Lutetia Parisorum, Île-de-France, France
    • University of Bordeaux
      Burdeos, Aquitaine, France
  • 1992–1993
    • Atomic Energy and Alternative Energies Commission
      Fontenay, Île-de-France, France