Energy Resolution Performance of the CMS Electromagnetic Calorimeter

The energy resolution performance of the CMS lead tungstate crystal electromagnetic calorimeter is presented. Measurements were made with an electron beam using a fully equipped supermodule of the calorimeter barrel. Results are given both for electrons incident on the centre of crystals and for electrons distributed uniformly over the calorimeter surface. The electron energy is reconstructed in matrices of 3 times 3 or 5 times 5 crystals centred on the crystal containing the maximum energy. Corrections for variations in the shower containment are applied in the case of uniform incidence. The resolution measured is consistent with the design goals

Construction du bouchon du calorimètre électromagnétique d'ATLAS et études de ses performances

ATLAS is one of the four experiments which will take place at the LHC, the CERN future protons collider. This accelerator, which should start in 2007, will allow to continue the studies carried out by its predecessors, as the standard model Higgs boson and new physics searches. The very high luminosity - 10 fb-1 during the first three functioning years, then 100 fb-1 - and the 14 TeV in the frame center will ease these studies. The Centre de Physique des Particules de Marseille took part in the ATLAS collaboration, taking in charge half of the Encap electromagnetic calorimeter modules construction. The description of this sub-detector and the construction steps, in particular the electrical tests which allow the stacking validation, are presented in this document. These tests results, obtained for the five first production modules, are analysed. The pre-series module (module 0) performances, obtained with beam tests performed at CERN in 1999, are also presented. The detector uniformity studies have allowed to perform important improvements on the calorimeter components. A 0.6% global constant term has been determined in the Endcap internal region (wheel).ATLAS est l'une des quatre expériences qui fonctionneront auprès du LHC, le futur collisionneur à protons du CERN. Cet accélérateur, dont le démarrage est prévu en 2007, permettra de prolonger les études menées auprès de ses prédécesseurs, telles que les recherches du boson de Higgs du modèle standard ou de signatures d'une nouvelle physique. Ces études seront facilitées par la puissance du LHC : énergie de 14 TeV dans le centre de masse et luminosité intégrée annuelle de 10 fb-1 durant les trois premières années, puis de 100 fb-1. Dans le cadre de la collaboration ATLAS, le Centre de Physique des Particules de Marseille a en charge, entre autre, la construction de la moitié des modules qui composent le bouchon du calorimètre électromagnétique. La description de ce sous-détecteur et les étapes de sa construction, en particulier les tests électriques qui permettent la validation du montage de chaque module, sont présentées dans ce document. Les résultats de ces tests, obtenus pour les cinq premiers modules de série, sont analysés. Les performances d'un module de pré-série (module 0), testé sous faisceau au CERN en 1999, sont également exposées. Les études menées sur l'uniformité de la réponse du détecteur ont permis d'effectuer des améliorations importantes sur les constituants du calorimètre. Un terme constant global de 0.6% a été déterminé dans la partie (roue) interne du bouchon

Construction du bouchon du calorimètre électromagnétique d'ATLAS et études de ses performances.

ATLAS est l'une des quatre expériences qui fonctionneront auprès du LHC, le futur collisionneur à protons du CERN. Cet accélérateur, dont le démarrage est prévu en 2007, permettra de prolonger les études menées auprès de ses prédécesseurs, telles que les recherches du boson de Higgs du modèle standard ou de signatures d'une nouvelle physique. Ces études seront facilitées par la puissance du LHC : énergie de 14 TeV dans le centre de masse et luminosité intégrée annuelle de 10 fb-1 durant les trois premières années, puis de 100 fb-1. Dans le cadre de la collaboration ATLAS, le Centre de Physique des Particules de Marseille a en charge, entre autre, la construction de la moitié des modules qui composent le bouchon du calorimètre électromagnétique. La description de ce sous-détecteur et les étapes de sa construction, en particulier les tests électriques qui permettent la validation du montage de chaque module, sont présentées dans ce document. Les résultats de ces tests, obtenus pour les cinq premiers modules de série, sont analysés. Les performances d'un module de pré-série (module 0), testé sous faisceau au CERN en 1999, sont également exposées. Les études menées sur l'uniformité de la réponse du détecteur ont permis d'effectuer des améliorations importantes sur les constituants du calorimètre. Un terme constant global de 0.6 % a été déterminé dans la partie interne du bouchon.LYON1-BU.Sciences (692662101) / SudocSTRASBOURG-Bib.Central Recherche (674822133) / SudocSudocFranceF

Search for significant background fluctuations in the EUSO-Balloon data

International audienceThe EUSO-Balloon instrument recorded data during a stratospheric flight in August 2014, to measure the UV background during a moonless night, from an altitude of ∼ 38 km, with a field of view of ±5.5 ◦ . In this paper, we report on the search for coherent fluctuations of this background over areas ranging from ∼ 1 km2 up to the entire field of view, on timescales from a few µs to ∼ 100µs. In addition to the expected laser track events induced by shootings from a helicopter flying in the field-of-view of EUSO-Balloon during part of the mission, three unidentified and significant events, probably related to human activity, are discussed

Single event effects testing of the RD53B chip

International audienceThe RD53 collaboration has been working since 2014 on the development of pixel chips for the CMS and ATLAS Phase 2 tracker upgrade. This work has recently led to the development of the RD53B full-scale readout chip which is using the 65nm CMOS process and containing 153600 pixels of 50 × 50 μm$^{2}$ The RD53B chip is designed to be robust against the Single Event Effects (SEE), allowing such a complex chip to operate reliably in the hostile environment of the HL-LHC. Different SEE mitigation techniques based on the Triple Modular Redundancy (TMR) have been adopted for the critical information in the chip. Furthermore, the efficiency of this mitigation scheme has been evaluated for the RD53B chip with heavy ion beams in the CYCLONE facility and with a 480 MeV proton beam in TRIUMF facility. The purpose of this paper is to describe and explain all the SEE mitigation strategies used in the RD53B chip, to report and analyze the heavy ions and proton tests results and to estimate the expected Single Event Upset (SEU) rates at the HL-LHC

Process studies at the air-sea interface after atmospheric deposition in the Mediterranean Sea: objectives and strategy of the PEACETIME oceanographic campaign (May–June 2017)

In spring, the Mediterranean Sea, a well-stratified low nutrient low chlorophyll region, receives atmospheric deposition both desert dust from the Sahara and airborne particles from anthropogenic sources. Such deposition translates into a supply of new nutrients and trace metals for the surface waters that likely impact biogeochemical cycles. However, the quantification of the impacts and the processes involved are still far from being assessed in situ. In this paper, we provide a state of the art regarding dust deposition and its impact on the Mediterranean Sea biogeochemistry and we describe in this context the objectives and strategy of the PEACETIME project and cruise, entirely dedicated to filling this knowledge gap. Our strategy to go a step forward than in previous approaches in understanding these impacts by catching a real deposition event at sea is detailed. The PEACETIME oceanographic campaign took place in May–June 2017 and we describe how we were able to successfully adapt the planned transect in order to sample a Saharan dust deposition event, thanks to a dedicated strategy, so-called Fast Action. That was successful, providing, for the first time in our knowledge, a coupled atmospheric and oceanographic sampling before, during and after an atmospheric deposition event. Atmospheric and marine in situ observations and process studies have been conducted in contrasted area and we summarize the work performed at sea, the type of data acquired and their valorization in the papers published in the special issue

Introduction: Process studies at the air–sea interface after atmospheric deposition in the Mediterranean Sea – objectives and strategy of the PEACETIME oceanographic campaign (May–June 2017)

International audienc

Production Testing and Quality Assurance of CMS Silicon Microstrip Tracker Readout Chips

The APV25 is the 128 channel CMOS chip developed for readout of the silicon microstrip tracker in the CMS experiment at the CERN Large Hadron Collider. The detector is now under construction and will be the largest silicon microstrip system ever built, with ~200m^2 of silicon sensors. Around 10^5 chips are required to instrument the system, which must operate for about 10 years in a high radiation environment with little or no possibility of microstrip system ever built, with ~200m^2 of silicon sensors. Around 10^5 chips are required to instrument the system, which must operate for about 10 years in a high radiation environment with little or no possibility of assurance of long term performance of the readout electronics, especially verification of radiation tolerance, is highly desirable. This has been achieved by means of automated probe testing of every chip on the silicon wafers from the foundry, followed by studies of sample die to evaluate in more detail properties of the chips which cannot easily be examined at the wafer level. During production, it was observed that the yield of good die varied unexpectedly from one production lot to another. This was investigated with significant help from the manufacturer and the process was optimised ensure a consistent high yield. A fraction of the dies, which successfully passed the wafer screening, are subjected to short term X-ray irradiation to levels equivalent to that expected in CMS and annealed. Results are presented here and illustrate the excellent performance of APV25 under all conditions

Performance of the EUSO-Balloon UV Camera

International audienceJEM-EUSO [1] is intended to be a space-borne fruorescence te lescope onboard of JEM/EF (Japanese Experimental Modeul/Exposure Facility) on the International Space Station (ISS). The main goal of the JEM-EUSO project is to detect the Extensive A ir Showers (EAS) produced by the Extreme Energy Cosmic Rays (EECRs) with energies above 1 0 19 eV from the extragalactic objects. As a pathfinder, the JEM-EUSO collaboration is curr ently developing a balloon-borne fluorescence telescope experiment, called EUSO-Balloon, f unded by CNES, the French space agency. It will perform end-to-end tests of the JEM-EUSO sub systems and instrumental concept, and measure the UV background for space-based EECR detector s. It involves several French in- stitutes (LAL, APC and IRAP) as well as several key institute s of the JEM-EUSO collaboration. The EUSO-Balloon instrument consists of an UV telescope and an infrared camera. The UV telescope will be operated at an altitude of 40 km to observe t he background and possibly signal photons in the fluorescence UV range (290-430 nm), which are e mitted along shower tracks gen- erated by ultra high energy cosmic rays with energies above 1 0 18 eV interacting with the earth’s atmosphere. The balloon experiment will be equipped with el ectronics and acquisition systems, as close as possible to the ones designed for the UV telescope of main JEM-EUSO instrument. The past years have been devoted to the design, the fabricati on and the tests of the prototype boards of the PDM, of the digital processor, and the flight mod els of optics, electronics and the IR camera for EUSO-Balloon. Here we focus on the PDM, the core element of the JEM-EUSO foca l surface. We first describe all key items of the PDM, from the photodetectors to the FPGA b oard, the first stage of the data processing (DP). We then report on the tests carried out on th e integration to assess their func- tionality and their suitability for a balloon mission