Micropattern gas detector technologies and applications, the work of the RD51 collaboration

The RD51 collaboration was founded in April 2008 to coordinate and facilitate efforts for development of micropattern gaseous detectors (MPGDs). The 75 institutes from 25 countries bundle their effort, experience and resources to develop these emerging micropattern technologies. MPGDs are already employed in several nuclear and high-energy physics experiments, medical imaging instruments and photodetection applications; many more applications are foreseen. They outperform traditional wire chambers in terms of rate capability, time and position resolution, granularity, stability and radiation hardness. RD51 supports efforts to make MPGDs also suitable for large areas, increase cost-efficiency, develop portable detectors and improve ease-of-use. The collaboration is organized in working groups which develop detectors with new geometries, study and simulate their properties, and design optimized electronics. Among the common supported projects are creation of test infrastructure such as beam test and irradiation facilities, and the production workshop.Comment: Submitted to the IEEE Nuclear Science Symposium 2010 Conference Recor

Gas Electron Multipliers versus Multiwire Proportional Chambers

Gas Electron Multiplication technology is finding more and more applications in beam instrumentation and at CERN these detectors have recently been adapted for use in transverse profile measurements at several of our facilities. In the experimental areas of CERN's Antiproton Decelerator, low energy Gas Electron Multipliers successfully replaced all Multwire Proportional Chambers in 2012 and another detector type has now been developed for high energy applications in the experimental areas of the SPS, totaling a potential of more than a hundred profile detectors to be replaced by GEM detectors of different types. This paper aims to describe the historical evolution of GEM technology by covering the many different applications but with specific focus on its potential to replace Multiwire Proportional Chambers for standard transverse profile measurement.Comment: Presented at IBIC 2013, Oxfor

Réorganisations cérébrales fonctionnelles dans la dysarthrie parkinsonienne

The three main cerebral dysfunctions associated with upper limb movements in Parkinson's disease (PD) are 1/ an underactivation of the supplementary motor area (SMA) and the dorsolateral prefrontal cortex (DLPFC), 2 /an overactivation of the primary motor cortex (M1) corresponding to the upper limb somatotopy and 3/ an overactivation of the cerebellum. The dysfunction of the motor circuit implying the basal ganglia (BG) seems to be compensated by the increased activation of the cortex-cerebellum-cortex loop. Regards to speech production in PD, the changes displayed are 1/an overactivation of the rostral part of the SMA and the DLPFC, 2 /an underactivation of the M1 cortex corresponding to the orofacial somatotopy and 3/ an underactivation of the cerebellum. These results reinforce the fact that the two parallel motor circuitries, involving the BG and the cerebellum respectively, are implicated in speech motor control. In PD, the dysfunction of the first circuit seems to deteriorate the activation of the second. An experimental task combining the two types of movements (of the upper limb and speech production) revealed an absence of motor area activations (M1 cortex, cerebellum) associated with speech production: the profile of hand movements was only observed; it seems that in PD, a loss of functional additivity regards to cerebral activations should be expected.Les trois principales dysfonctions cérébrales observées lors de mouvements réalisés avec le membre supérieur dans la maladie de Parkinson (MP) sont 1/ une hypoactivation de l'aire motrice supplémentaire (AMS) et du cortex dorsolatéral préfrontal (DLPFC), 2/ une hyperactivation du cortex moteur primaire (M1) correspondant à la somatotopie du membre supérieur et 3/ une hyperactivation du cervelet. Le dysfonctionnement du circuit moteur impliquant les noyaux gris centraux (NGC) semble compensé par l'activation accrue de la boucle cortex-cervelet-cortex. Lors de la production de parole dans la MP, sont observées 1/ une hyperactivation de la partie rostrale de l'AMS et du DLPFC, 2/ une hypoactivation du cortex M1 correspondant à la somatotopie orofaciale et 3/ une hypoactivation du cervelet. Ces résultats renforcent le fait que les deux circuits moteurs parallèles, impliquant respectivement les NGC et le cervelet, sont impliqués dans le contrôle moteur de la production de parole. Dans la MP, le dysfonctionnement du premier circuit semble altérer l'activation du deuxième. Une tâche expérimentale combinant les deux types de mouvements (du membre supérieur et de la parole) a révélé une absence d'activation des aires motrices (cortex M1, cervelet) associées à la production de parole : seul le profil lié au mouvement de la main a été observé; il y aurait perte, dans la MP, de l'additivité fonctionnelle des activations cérébrales

RD51, an R&D collaboration for micropattern gaseous detectors

The RD51 collaboration was founded in April 2008 to coordinate and facilitate efforts for development of micropattern gaseous detectors (MPGDs). The 59 institutes from 20 countries bundle their effort, experience and resources to develop these emerging micropattern technologies. MPGDs are already employed in several nuclear and high-energy physics experiments, medical imaging instruments and photodetection applications; many more applications are foreseen. They outperform traditional wire chambers in terms of rate capability, time and position resolution, granularity, stability and radiation hardness. RD51 supports efforts to make MPGDs also suitable for large areas, increase cost-efficiency, develop portable detectors and improve ease-of-use. The collaboration is organized in working groups which develop detectors with new geometries, study and simulate their properties, and design optimized electronics. Among the common supported projects are creation of test infrastructure such as beam test and irradiation facilities, and the production workshop.Comment: Invited contribution to the XLVII international winter meeting on nuclear physics, Bormio, January 200

Gas Electron Multipliers for the Antiproton Decelerator

The new beam profile measurement for the Antiproton Decelerator (AD) at CERN is based on a single Gas Electron Multiplier (GEM) with a 2D readout structure. This detector is very light (~0.4% X0), and measures horizontal and vertical profiles directly in one plane. This overcomes the problems previously encountered with multi-wire proportional chambers for the same purpose, where beam interactions with the detector severely affect the obtained profiles. A prototype was installed and successfully tested in late 2010, with another five detectors now installed in the ASACUSA and AEGIS beam lines. This paper will provide a detailed description of the detector and discuss the results obtained.Comment: Paper presented at DIPAC 2011, Hambur

The Dysarthria Impact Profile: a preliminary French experience with Parkinson’s disease.

International audienceThis preliminary study aimed to adapt the Dysarthria Impact Profile (DIP) in French and to confirm its relevance for the assessment of the psychosocial impact of dysarthria in Parkinson's disease (PD). The DIP scale was administered to 10 people with PD and 10 age-matched control subjects. The DIP psychometric properties were calculated (discriminant validity, internal consistency, concurrent validity), notably by using the Voice Handicap Index (VHI) for inter-scale comparisons. The French version of the DIP discriminated people with PD from control subjects (χ² test, p < 0.05). Good internal consistency was observed in both populations (Cronbach’s α = 0.93 for PD people and α = 0.76 for control subjects). The DIP was highly correlated (Spearman’s ρ correlation) with the VHI (ρ = -0.70, p<0.01), confirming the external validity of the scale. There was no direct relationship between PD speech and quality of life as assessed by the PDQ-39. Our preliminary data suggest that the French version of the DIP has the potential to make a useful contribution for the assessment and outcome management in acquired dysarthria for both clinicians and researchers

Cinquante ans de recherches au Laboratoire Parole et Langage : vers une linguistique des interfaces

Le LPL, Laboratoire Parole et Langage (UMR 7309 CNRS/Aix-Marseille Université) fête en 2022 cinquante ans d’association au CNRS. C’est en réalité de soixante ans d’existence en tant que laboratoire d’université dont peut s’enorgueillir le LPL en 2022. Les membres du laboratoire se sont mobilisés à cette occasion pour se raconter, exposer idées, concepts et résultats, à travers un prisme qui leur est propre et qui est le fruit de plus de cinquante ans d’interrogation des marges, bordures et au..

Spherical GEMs for parallax-free detectors

We developed a method to make GEM foils with a spherical geometry. Tests of this procedure and with the resulting spherical \textsc{gem}s are presented. Together with a spherical drift electrode, a spherical conversion gap can be formed. This would eliminate the parallax error for detection of x-rays, neutrons or UV photons when a gaseous converter is used. This parallax error limits the spatial resolution at wide scattering angles. The method is inexpensive and flexible towards possible changes in the design. We show advanced plans to make a prototype of an entirely spherical triple-GEM detector, including a spherical readout structure. This detector will have a superior position resolution, also at wide angles, and a high rate capability. A completely spherical gaseous detector has never been made before.Comment: Contribution to the 2009 IEEE Nuclear Science Symposium, Orlando, Florid