Charged particle detection performances of CMOS pixel sensors produced in a 0.18 um process with a high resistivity epitaxial layer

The apparatus of the ALICE experiment at CERN will be upgraded in 2017/18 during the second long shutdown of the LHC (LS2). A major motivation for this upgrade is to extend the physics reach for charmed and beauty particles down to low transverse momenta. This requires a substantial improvement of the spatial resolution and the data rate capability of the ALICE Inner Tracking System (ITS). To achieve this goal, the new ITS will be equipped with 50 um thin CMOS Pixel Sensors (CPS) covering either the 3 innermost layers or all the 7 layers of the detector. The CPS being developed for the ITS upgrade at IPHC (Strasbourg) is derived from the MIMOSA 28 sensor realised for the STAR-PXL at RHIC in a 0.35 um CMOS process. In order to satisfy the ITS upgrade requirements in terms of readout speed and radiation tolerance, a CMOS process with a reduced feature size and a high resistivity epitaxial layer should be exploited. In this respect, the charged particle detection performance and radiation hardness of the TowerJazz 0.18 um CMOS process were studied with the help of the first prototype chip MIMOSA 32. The beam tests performed with negative pions of 120 GeV/c at the CERN-SPS allowed to measure a signal-to-noise ratio (SNR) for the non-irradiated chip in the range between 22 and 32 depending on the pixel design. The chip irradiated with the combined dose of 1 MRad and 10^13 n_eq/cm^2 was observed to yield a SNR ranging between 11 and 23 for coolant temperatures varying from 15 C to 30 C. These SNR values were measured to result in particle detection efficiencies above 99.5% and 98% before and after irradiation respectively. These satisfactory results allow to validate the TowerJazz 0.18 um CMOS process for the ALICE ITS upgrade.Comment: (v2) Added hyper-links; (v3) A typo correcte

Development of CMOS pixel sensors for tracking and vertexing in high energy physics experiments

CMOS pixel sensors (CPS) represent a novel technological approach to building charged particle detectors. CMOS processes allow to integrate a sensing volume and readout electronics in a single silicon die allowing to build sensors with a small pixel pitch ($\sim 20 \mu m$) and low material budget ($\sim 0.2-0.3\% X_0$) per layer. These characteristics make CPS an attractive option for vertexing and tracking systems of high energy physics experiments. Moreover, thanks to the mass production industrial CMOS processes used for the manufacturing of CPS the fabrication construction cost can be significantly reduced in comparison to more standard semiconductor technologies. However, the attainable performance level of the CPS in terms of radiation hardness and readout speed is mostly determined by the fabrication parameters of the CMOS processes available on the market rather than by the CPS intrinsic potential. The permanent evolution of commercial CMOS processes towards smaller feature sizes and high resistivity epitaxial layers leads to the better radiation hardness and allows the implementation of accelerated readout circuits. The TowerJazz $0.18 \mu m$ CMOS process being one of the most relevant examples recently became of interest for several future detector projects. The most imminent of these project is an upgrade of the Inner Tracking System (ITS) of the ALICE detector at LHC. It will be followed by the Micro-Vertex Detector (MVD) of the CBM experiment at FAIR. Other experiments like ILD consider CPS as one of the viable options for flavour tagging and tracking sub-systems

Tracking in the context of the European project AIDA

Ce travail se place dans le contexte du détecteur de vertex (VXD) composé de capteurs CMOS pour l'ILC, et dans celui du télescope en faisceau du projet européen AIDA. La thèse inclut les tests en faisceau des éléments du télescope AIDA : les super-plans SALAT et les échelles double faces PLUME. Elle questionne la valeur ajoutée en terme d'alignement, des couches double faces de capteurs CMOS pour le VXD de l'ILD. Une nouvelle méthode d'alignement autonome de chacune des 3 double couches du VXD grâce aux mini-vecteurs construits sur chaque zone de recouvrement inter-échelle est proposée et a été testée avec des particules de haute impulsion. Cependant, seules les particules du bruit de fond faisceau, de plus basses impulsions, permettent l'obtention d'une statistique suffisante pour cet alignement. Ce bruit de fond a alors été étudié et une estimation des taux d'occupation des capteurs du VXD a conduit à une ré-estimation des vitesses de lecture des capteurs de chaque couche du VXD.This work was conducted in the context of a vertex detector (VXD) composed of CMOS sensors for ILD and in the context of the beam telescope of the european project AIDA. The provides the results of beam tests for the new telescope components : the SALAT super-planes and the PLUME double sided ladders. The thesis adresses the added value in terms of alignment, of double sided layers of CMOS sensors for the VXD of ILD. A new standalone alignment method of each of the three double sided layers of VXD with the mini-vectors built on each overlapping zone between the consecutive ladders is analysed. Such alignment was validated with high momentum particles. However, only the beam background particles, with lower momentum, can provide the minimum statistic for this kind of alignment. Thus, the beam background noise was studied and the occupancy rate of the VXD sensors was studied. This led to a reassessment of the readout speed for the sensors of each layer of the VXD

Tracking in the context of the European project AIDA

Ce travail se place dans le contexte du détecteur de vertex (VXD) composé de capteurs CMOS pour l'ILC, et dans celui du télescope en faisceau du projet européen AIDA. La thèse inclut les tests en faisceau des éléments du télescope AIDA : les super-plans SALAT et les échelles double faces PLUME. Elle questionne la valeur ajoutée en terme d'alignement, des couches double faces de capteurs CMOS pour le VXD de l'ILD. Une nouvelle méthode d'alignement autonome de chacune des 3 double couches du VXD grâce aux mini-vecteurs construits sur chaque zone de recouvrement inter-échelle est proposée et a été testée avec des particules de haute impulsion. Cependant, seules les particules du bruit de fond faisceau, de plus basses impulsions, permettent l'obtention d'une statistique suffisante pour cet alignement. Ce bruit de fond a alors été étudié et une estimation des taux d'occupation des capteurs du VXD a conduit à une ré-estimation des vitesses de lecture des capteurs de chaque couche du VXD.This work was conducted in the context of a vertex detector (VXD) composed of CMOS sensors for ILD and in the context of the beam telescope of the european project AIDA. The provides the results of beam tests for the new telescope components : the SALAT super-planes and the PLUME double sided ladders. The thesis adresses the added value in terms of alignment, of double sided layers of CMOS sensors for the VXD of ILD. A new standalone alignment method of each of the three double sided layers of VXD with the mini-vectors built on each overlapping zone between the consecutive ladders is analysed. Such alignment was validated with high momentum particles. However, only the beam background particles, with lower momentum, can provide the minimum statistic for this kind of alignment. Thus, the beam background noise was studied and the occupancy rate of the VXD sensors was studied. This led to a reassessment of the readout speed for the sensors of each layer of the VXD

Trajectomètrie dans le cadre du projet européen AIDA

This work was conducted in the context of a vertex detector (VXD) composed of CMOS sensors for ILD and in the context of the beam telescope of the european project AIDA. The provides the results of beam tests for the new telescope components : the SALAT super-planes and the PLUME double sided ladders. The thesis adresses the added value in terms of alignment, of double sided layers of CMOS sensors for the VXD of ILD. A new standalone alignment method of each of the three double sided layers of VXD with the mini-vectors built on each overlapping zone between the consecutive ladders is analysed. Such alignment was validated with high momentum particles. However, only the beam background particles, with lower momentum, can provide the minimum statistic for this kind of alignment. Thus, the beam background noise was studied and the occupancy rate of the VXD sensors was studied. This led to a reassessment of the readout speed for the sensors of each layer of the VXD.Ce travail se place dans le contexte du détecteur de vertex (VXD) composé de capteurs CMOS pour l'ILC, et dans celui du télescope en faisceau du projet européen AIDA. La thèse inclut les tests en faisceau des éléments du télescope AIDA : les super-plans SALAT et les échelles double faces PLUME. Elle questionne la valeur ajoutée en terme d'alignement, des couches double faces de capteurs CMOS pour le VXD de l'ILD. Une nouvelle méthode d'alignement autonome de chacune des 3 double couches du VXD grâce aux mini-vecteurs construits sur chaque zone de recouvrement inter-échelle est proposée et a été testée avec des particules de haute impulsion. Cependant, seules les particules du bruit de fond faisceau, de plus basses impulsions, permettent l'obtention d'une statistique suffisante pour cet alignement. Ce bruit de fond a alors été étudié et une estimation des taux d'occupation des capteurs du VXD a conduit à une ré-estimation des vitesses de lecture des capteurs de chaque couche du VXD

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Overview of ASTEC integral code status and perspectives

International audienceThe European severe accident integral code ASTEC, developed by IRSN, aims at simulating the progression and consequences of severe accidents (SA) in a water cooled nuclear power plant (NPP). In particular, in France, the current ASTEC V2 series version are and will be in the next five years intensively used to perform deterministic and probabilistic safety analyses addressing the lifetime extension of the French operating fleet and the start up of the EPR. This version is also used for emergency preparedness and response purposes. The benchmarking activities with MELCOR and MAAP on the Fukushima Daiichi accidents within the frame of the BSAF OCDE project evidenced significant discrepancies between SA codes likely to affect SAMG assessment. To deepen SA codes benchmarking, so called crosswalk activities are conducted to identify needed SA models enhancement for consolidation of SAMG assessment. These discrepancies are related to the complex modelling of the fuel degradation and relocation that includes coupled thermodynamic, thermal mechanic and thermal hydraulic processes and that is currently revisited in a coordinated way by the leading SA code development teams (USNRC/SNL, EPRI, IAE and IRSN).The elicitation of the SA modelling, its validation through dedicated and assessed experimental databases and its benchmarking on large sets of reactor configurations are the sound bases of SA codes. They will stay a subject of research and development at IRSN and they will be strengthened for ASTEC V2.1 by the users’ community through the NUGENIA ASCOM project coordinated by IRSN that started in autumn 2018.These bases are the pillars for the innovative trajectory of development of the next ASTEC series of versions that just started in 2019, named ASTEC+, with two main objectives:- to develop capacities to address any nuclear facility (NPP, spent fuel pool, fuel cycle facilities, material testing reactor, small modular reactor, Gen. IV concepts, nuclear fusion reactors…) and related risks,- to streamline and to pool the efforts in the safety evaluation chain: deterministic evaluations plus uncertainties, level 2 Probabilistic Safety Analyses, emergency preparedness and response, SA desktop simulator.Meeting these objectives at short term implies to reconsider globally the SA code development approach that was designed more than two decades ago to drastically improve the extendibility, the reusability, the verifiability and the ease of use of the code. IRSN has thus designed a new approach based on solutions that demonstrated their efficiency in various engineering contexts (object development, agile methods, advanced algorithms, high fidelity informed low fidelity models, surrogate models)

Radioactive Iodine in the Atmosphere : from source term to dose Status of IRSN research

International audienceIn case of an accident release, radioactive iodine isotope dispersion into the environment is a problem of main concern due to possible human health impact. Authorized discharges result sometimes in measurablelevels of radioactive iodine releases into the atmosphere also contributing to public concerns and interrogation – even if at trace level. The half life of some radioiodine isotopes (8 days for 131I and 15 millions years for 129I) implies a possible dispersion into all compartments of the environment – from the troposphere to the terrestrial or marine biosphere and finally into the food chain – inducing potential human health effects. The major accidents of Chernobyl and Fukushima or even the recent iodine release events detected in Europe have shown that the knowledge of the radioative iodine distribution between its various chemical forms is still insufficently accurate to satisfactorily adress the public concerns.Research at IRSN on iodine dispersion in the atmospheric compartment is aimed to adress the major issues of this problematic : 1/ accurate source term evaluation for realistic dose assement, 2/ improved crisismanagement to better protect the public in case of radioactive iodine release into the atmosphere.To perform these evaluations, IRSN relies on modelling tools dedicated to the evaluation of the source term(ASTEC, PERSAN, ... codes), and to the prediction of its dispersion into the environment taking into account the health impact (C3X, SYMBIOSE and CONDOR tools). Modelling tools are also completed byradioactive iodine monitoring in the environnment (OPERA Air program covering the whole french territory) and mobile in vivo measurement units dedicated to the monitoring of exposed populations. The Software tools allow for an accurate dose assessment.In order to improve its expertise and knowledge on radio-iodine behaviour in the atmosphere, IRSN is currently sustaining large research efforts over 6 thematics covering all the aspects linked to this issue: source term evaluation, atmospheric dispersion modelling including the terrestrial and marine boundaries, development of more sensitive and accurate monitoring equipement, dosimetry tools (ICARE and MIODOSE) and upgrade of prophylaxis policies (PRIODAC research program). Improved understanding of radio-iodine dispersion in the atmosphere in terms of speciation and physical forms can be obtained by combining experimental studies and development of new modelling schemes. Model validation will be gained by facing fields measurements in case of routine iodine discharge (129I or 131I to some extent) or accidental/incidental situation. In this view, the development of new field monitoring devices capable of identifying the nature of iodine (gaseous vs particulate material and iodine speciation) is a challenging issue. At least, the dose evaluation operationnal tools and the iodine prophylaxis policy will benefit from the dispersion model improvement.The ability of the nuclear safety field community to accurately characterize radio-iodine dispersion, dose evaluation and progress in the use of countermeasures is thus of utmost importance. Such high accuracydata will help to better advise authorities and emergency crisis managers to improve the protection of the public if a severe nuclear power plant accident is to occu

Personalized functional profiling using ex-vivo patient-derived spheroids points out the potential of an antiangiogenic treatment in a patient with a metastatic lung atypical carcinoid

International audienceLung carcinoids are neuroendocrine tumors representing 1 to 2% of lung cancers. This study outlines the case of a patient with a metastatic lung atypical carcinoid who presented with a pleural effusion and progression of liver metastases after developing resistance to conventional treatments. Personalized functional profiling (PFP), i.e. drug screening, was performed in ex-vivo spheroids obtained from the patient’s liver metastasis to identify potential therapeutic options. The drug screening results revealed cediranib, an antiangiogenic drug, as a hit drug for this patient, from a library of 66 Food and Drug Administration (FDA)-approved and investigational drugs. Based on the PFP results and the reported evidence of clinical efficacy of bevacizumab and capecitabine combination in gastro-intestinal neuroendocrine tumors, this combination was given to the patient. Four months later, the pleural effusion and pleura carcinosis regressed and the liver metastasis did not progress. The patient experienced 2 years of a stable disease under the PFP-guided personalized treatment