Optoelectronic analogue signal transfer for LHC detectors, 1991

We propose to study and develop opto-electronic analogue front-ends based on electro-optic intensity modulators. These devices translate the detector electrical analogue signals into optical signals which are then transferred via optical fibres to photodetector receivers at the remote readout. In comparison with conventional solutions based on copper cables, this technique offers the advantages of high speed, very low power dissipation and transmission losses, compactness and immunity to electromagnetic interference. The linearity and dynamic range that can be obtained are more than adequate for central tracking detectors, and the proposed devices have considerable radiation- hardness capabilities. The large bandwidth and short transit times offer possibilities for improved triggering schemes. The proposed R&D programme is aimed at producing multi-channel "demonstrator" units for evaluation both in laboratory and beam tests. This will allow the choice of the most effective technology. A detailed study will also be carried out on packaging and interconnection to large arrays of fibres, as well as on the optimization of the processes for the production of large quantities

Practical evaluation of fault countermeasures on an asynchronous DES cryptoprocessor

International audienceThis paper presents practical results on the evaluation of fault countermeasures implemented in an asynchronous DES coprocessor. The theory underlying the countermeasures was previously published in IOLTS 2005. For the first time this work reports a practical evaluation of fault countermeasures applied on asynchronous DES ASICs. Two DES crypto processors were fabricated using the 130 nm STmicroelectronics CMOS process; one as a reference and one hardened using a specific technique. This work enables us to compare the resistance of both circuits against fault injection and to validate the proposed countermeasures. The practical set-up of the fault injection, using a laser, is presented and the test campaign described. The practical results prove the efficiency of the method. The techniques can be applied to protect logic blocks in any applications

Experimental Evaluation of Protections Against Laser-induced Faults and Consequences on Fault Modeling

ISBN : 978-3-9810801-2-4International audienceLasers can be used by hackers to situations to inject faults in circuits and induce security flaws. On-line detection mechanisms are classically proposed to counter such attacks, and are often based on error detecting codes. However, the efficiency of such schemes has not been precisely validated against real attack conditions. This paper presents results showing that, with a given type of laser, a classical protection technique can leave open doors to an attacker. The results give also insights into the fault models to be taken into account when designing a secured circuit

Que reste-t-il de Friday Harbor ? Pour une approche critique renouvelée des usages du géoweb fondée sur l'analyse des traces numériques

Plus de 20 ans après la conférence de Friday Harbor, que reste-t-il des SIG critiques ? Face à l'opacité des portails Internet qui diffusent des données géographiques, comment tenter d'identifier et de qualifier les pratiques qui y sont associées ? Nous expérimentons une méthode dont l'objectif est de déconstruire le géoweb pour en révéler les usages. Il s'agit, d'une part, d'analyser les plateformes web qui diffusent des données géographiques en explorant leurs traces numériques et, d'autre part, de soumettre ces traces aux usagers eux-mêmes pour les amener à adopter une posture réflexive. En s'inspirant des visual studies et en particulier de la photo elicitation, nous proposons un retour sur l'intérêt de cette approche mixte, inductive et réflexive. Deux études de cas viennent illustrer notre proposition en s'intéressant à l'information géographique institutionnelle et volontaire. Ces exemples permettent d'alimenter une discussion sur la place de la géomatique dans la mise en oeuvre d'approches interdisciplinaires pour repenser la critique par le prisme des usages. ABSTRACT. More than 20 years after the Friday Harbor conference, what remains of 'Critical GIS' ? Given the opacity of Internet portals that disseminate geographic data, how can we identify and evaluate the associated practices? We developed a method that works by deconstructing the geoweb to reveal its uses. This requires, in the first instance, an analysis of web platforms for dissemination of geographic data through their digital footprints, then a return of these results to the users themselves to give them a chance to reflect on their choices. Based on visual studies, particularly photo-elicitation, we propose a return to mixed methods that are inductive and reflexive. Two case studies illustrate our approach, highlighting institutional and volunteer data sources. These examples contribute to a discussion of the development of interdisciplinary approaches to recast the critical approach in terms of uses and users. MOTS CLÉS : géoweb, usages, géomatique critique, infrastructure de données géographiques (IDG), OpenStreetMap (OSM).More than 20 years after the Friday Harbor conference, what remains of ‘Critical GIS’ ? Given the opacity of Internet portals that disseminate geographic data, how can we identify and evaluate the associated practices? We developed a method that works by deconstructing the geoweb to reveal its uses. This requires, in the first instance, an analysis of web platforms for dissemination of geographic data through their digital footprints, then a return of these results to the users themselves to give them a chance to reflect on their choices. Based on visual studies, particularly photo-elicitation, we propose a return to mixed methods that are inductive and reflexive. Two case studies illustrate our approach, highlighting institutional and volunteer data sources. These examples contribute to a discussion of the development of interdisciplinary approaches to recast the critical approach in terms of uses and users

Particle and x-ray generation by irradiation of gaseous and solid targets with a 100TW laser pulse, Plasma Phys. Control. Fusion 51

The recently commissioned 100 TW, TiSa laser system (2.5 J, 25 fs) at the University of Dusseldorf has been used to study various issues at relativistic intensities including interaction physics, electron and proton acceleration and higher surface harmonics. The plasma evolution during and after laser pulse propagation through underdense gaseous targets was investigated with an optical probe pulse. Under similar experimental conditions the electron beam was recorded with Lanex screens and an electron spectrometer. On solid thin foil targets the production of protons was studied using a magnetic spectrometer. Due to the high contrast of the laser pulse, foil targets as thin as 300 nm could be used. Higher harmonics from laser irradiated fused silica targets were observed