Single Event Effects in CMOS Image Sensors

In this work, 3T Active Pixel Sensors (APS) are exposed to heavy ions (N, Ar, Kr, Xe), and Single Event Effects (SEE) are studied. Devices were fully functional during exposure, no Single Event Latch-up (SEL) or Single Event Functional Interrupt (SEFI) happened. However Single Event Transient (SET) effects happened on frames: line disturbances, and half or full circular clusters of white pixels. The collection of charges in cluster was investigated with arrays of two pixel width (7 and 10 \textmu{}m), with bulk and epitaxial substrates. This paper shows technological and design parameters involved in the transient events. It also shows that STARDUST simulation software can predict cluster obtained for bulk substrate devices. However, the discrepancies in epitaxial layer devices are large - which shows the need for an improved model

ZnGa2Se4, a nonlinear material with wide mid infrared transparency and good thermomechanical properties

International audienceDuring the last decades, mid-infrared (3-12 μm) laser sources using crystals with nonlinear optical properties have attracted a particular attention due to their potential applications in different fields such as optical countermeasures and remote chemical sensing. As transparency of common oxide crystals is limited to about 4 μm, many researches have been focused on chalcopyrite compounds because of their wide transparency in the mid-IR range and their strong nonlinear optical coefficients. There is a need of such crystals able to convert efficiently the near infrared wavelengths from commercially available lasers into wavelengths higher than 5 μm through Optical Parametric Oscillators (OPO) systems. This paper presents a new compound: ZnGa 2 Se 4 (ZGSe). Measurements made on dense polycrystals show a high thermal conductivity value in comparison with other selenides (2.9 W m −1 K −1), a wide transparency from visible to beyond the band III of the mid IR (0.6 μm-17 μm) and a coefficient of thermal expansion inferior to 10^−5 K^−1. These results are very encouraging and improvements of the growth process are now undertaken to obtain single crystals with the required optical quality

Exact recovery of the support of piecewise constant images via total variation regularization

This work is concerned with the recovery of piecewise constant images from noisy linear measurements. We study the noise robustness of a variational reconstruction method, which is based on total (gradient) variation regularization. We show that, if the unknown image is the superposition of a few simple shapes, and if a non-degenerate source condition holds, then, in the low noise regime, the reconstructed images have the same structure: they are the superposition of the same number of shapes, each a smooth deformation of one of the unknown shapes. Moreover, the reconstructed shapes and the associated intensities converge to the unknown ones as the noise goes to zero

Towards Off-the-grid Algorithms for Total Variation Regularized Inverse Problems

We introduce an algorithm to solve linear inverse problems regularized with the total (gradient) variation in a gridless manner. Contrary to most existing methods, that produce an approximate solution which is piecewise constant on a fixed mesh, our approach exploits the structure of the solutions and consists in iteratively constructing a linear combination of indicator functions of simple polygons.Comment: For the short conference version see arXiv:2104.06706v2. For the long journal version see arXiv:2104.06706v

George Weigel, Le catholicisme évangélique

Le catholicisme a-t-il encore un avenir ? Telle est la question qui barre la jaquette de l’édition française du livre de George Weigel, essayiste américain bien connu pour sa biographie de Jean-Paul II. Le sous-titre original sous lequel il est paru en 2013 correspond davantage à son contenu : « Evangelical Catholicism. Deep Reform in the 21st-Century Church ». En effet, George Weigel ne doute à aucun moment que le catholicisme ait un avenir : le ton est assuré, construit sur de solides convi..

Fanny Gribenski, L’Église comme lieu de concert. Pratiques musicales et usages de l’espace (Paris, 1830-1905)

Fanny Gribenski appartient à cette école de jeunes musicologues français particulièrement féconde et dynamique qui s’attache avec bonheur à renouveler un champ largement laissé en jachère. Sa thèse, soutenue le 9 décembre 2015 à l’EHESS, s’inscrit dans la lignée des travaux de Patrice Veit, Rémy Campos, Thierry Favier, mais aussi Jann Pasler (La République, la musique et le citoyen 1871-1914) et Katharine Ellis (The Politics of Plainchant in fin-de-siècle France), et surtout Xavier Bisaro, à ..

Displacement damage effects due to neutron and proton irradiations on CMOS image sensors manufactured in deep submicron technology

Displacement damage effects due to proton and neutron irradiations of CMOS image sensors dedicated to imaging are presented through the analysis of the dark current behavior in pixel arrays and isolated photodiodes. The mean dark current increase and the dark current nonuniformity are investigated. Dark current histogram observations are compared to damage energy distributions based on GEANT 4 calculations. We also discuss, through annealing analysis, which defects could be responsible for the dark current in CMOS image sensors