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2021-06-15
17:50
Module development for the ATLAS ITk Pixel Detector
Reference: Poster-2021-1049
Created: 2021. -1 p
Creator(s): Mobius, Silke

In HL-LHC operation the instantaneous luminosity will reach unprecedented values, resulting in about 200 proton-proton interactions in a typical bunch crossing. The current ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk). The innermost part of ITk will consist of a state-of-the-art pixel detector. The individual modules of the ITk Pixel Detector comprise silicon sensors using various different technologies, with the sensors read out using the new ITKpix ASIC. In this talk we will present results from first prototype modules using the new ASIC.

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2021-06-14
17:10
Best Practice Guide on Pollutant Dispersion Simulations with the Commercial Tool „ ANSYS Fluent“ at CERN
Reference: Poster-2021-1048
Keywords:  Large Eddy Simulation (LES), neutral Atmospheric Boundary Layer (ABL), Synthetic Turbulence Generator (STG), Monin-Obukhov similarity theory, pollutant dispersion, discrete phase model (DPM), Computational Fluid Dynamics (CFD)
Created: 2021. -7 p
Creator(s): Kauflin, Uwe; Battistin, Michele; La Mendola, Saverio; Leitl, Bernd

Large Eddy Simulations (LES) are of raising interest for numerous engineering applications in which an accurate flow prediction is necessary. This paper searches for the optimum mesh resolution in numerical simulations reliably predicting dispersion of pollutants in the lower part of the Atmospheric Boundary Layer (ABL). For the dispersion of pollutants, turbulent quantities have been assessed at several distances from the release point and compared to each other. Areas close to release points located at low altitudes are given a particular importance, because air pollutant concentrations can be too high for people present at such places. To achieve a realistic prediction of the flow and pollutant concentrations close to populated areas, LES are preferred over the Reynolds-Averaged Navier Stokes (RANS) models (Vita et al, 2020). A mesh resolution of 0.5 m is recommended at distances from the release point shorter than 40 m. Near the release point, physical effects like building downwash and horizontal plume enlargement due to the downstream wake region of buildings have a direct impact on pollutant concentrations and particle trajectories. In built-up areas at intermediary distances where the dispersion of the plume is directly influenced by buildings in their given constellation and where the energy production is high, a mesh resolution of 1.5 m is suggested. In areas where the plume is already dispersed and geometrical obstacles are rare, a mesh resolution of 3 m and more is sufficient. In these areas, the dissipation of energy and the transport of particles (mean quantities) that determine the flow are less affected by the mesh size.

Related links:
20th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes
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2021-05-28
12:08
A large Scintillating Fibre Tracker for LHCb
Reference: Poster-2021-1047
Created: 2021. -1 p
Creator(s): Berninghoff, Daniel Alexander

The LHCb detector is currently being upgraded to cope with higher instantaneous luminosities and to read out data at 40 MHz using a trigger-less read-out system. The new main tracker consists of 250µm thick scintillating fibres (SciFi) and covers an area of 340 m2. The tracker provides a spatial resolution for charged particles better than 80 µm. The scintillation light is recorded with arrays of multi-channel silicon photomultipliers (SiPMs). A custom ASIC is used to digitize the SiPM signals and subsequent digital electronics performs clustering and data-compression. Single detector modules are mounted on so-called C-frames (3m × 6m) which will provide the mechanical support and the necessary services. The serial assembly of the 12 large frames, each comprising 50,000 SiPM channels, is progressing and the first detector elements have been commissioned. This presentation will cover the development, construction and the commissioning results of the detector.

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2021-05-28
12:06
LHCb RMS-R3 — new radiation hard system for on-line monitoring of beam and background conditions in Run 3
Reference: Poster-2021-1046
Created: 2021. -1 p
Creator(s): Dobishuk, Vasyl; Alessio, Federico; Chernyshenko, Serhii; Okhrimenko, Oleksandr; Pugatch, Valery

During Run 3, the LHCb experiment will collect data at a higher luminosity with respect to the previous decade of data taking. The Radiation Monitoring System (RMS-R3) will display the interaction rate of the LHC’s beams along with its background in LHCb. The RMS-R3 comprises four detector modules based on the Metal-Foil Detectors radiation hard technology that can withstand fluences up to 1020 MIPs/cm2 or radiation doses of up to a GGy, during its entire lifespan. The modules are placed symmetrically around the beam pipe very close to the Interaction Point at LHCb at a distance of about 2.2 m, while covering a backward acceptance of 7–14 degrees. The readout electronics provide a continuous relative luminosity measurement for LHCb and observations of background evolutions during the various stages of the beam preparation towards collisions. The RMS-R3 detector's performance has shown good response reproducibility of about 1% and excellent linearity.

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2021-05-28
12:02
The upgrade of the LHCb RICH detector
Reference: Poster-2021-1045
Created: 2021. -1 p
Creator(s): Bartolini, Matteo

The two LHCb RICH detectors have provided excellent particle ID until the end of Run2 in 2018 operating at the luminosity of ∼4×1032 cm−2s−1. From the beginning of Run3 in 2022, the Level 0 hardware trigger of the experiment will be removed to allow data readout at the full LHC collision rate of 40 MHz and the luminosity will be increased to ∼2×1033 cm−2s−1. In order to adapt the RICH system to the new rate, the current HPD detectors with embedded electronics limited to readout event rate of 1 MHz have been replaced by MaPMTs with external readout electronics. Moreover, in order to reduce the occupancy of the photon detectors due to the higher luminosity, a reoptimization of the optics is required. In this talk the upgraded opto-electronics chain and the performance expected for Run3 will be presented together with the automated quality control procedures to qualify the RICH photon detectors and support electronics.

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2021-05-28
11:59
Novel photon timing techniques in the LHCb RICH upgrade programme
Reference: Poster-2021-1044
Created: 2021. -1 p
Creator(s): Keizer, Floris

The Ring-Imaging Cherenkov (RICH) detectors at LHCb have an excellent intrinsic time resolution owing to the prompt Cherenkov radiation and focusing mirrors optics. While only spatial information has been used in the experiment to date, the addition of photon time information is one of the cornerstones of the RICH upgrade programme. The novel timing techniques presented on this poster provide a powerful tool for background suppression and particle ID performance improvements using state of the art electronics.

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2021-01-29
12:31
Exhibition - visit circuit: the history of the CERN Data Centre
Exposition - Circuit de visites : l'histoire du Centre de calcul du CERN

Reference: Poster-2021-1043
Keywords:  computing  history  Data Centre  Centre de calcul  Computing Centre
Created: 2020. -10 p
Creator(s): Gaillard, Melissa; Perrey, Melissa Loyse

These ten panels have been installed in building 49 (corridor linking building 31 to 513) as part of the visit circuit. They give an overview of the history of the CERN Data Centre between CERN's creation and 2020. Languages : French and EnglishCes 10 panneaux ont été installés dans le bâtiment 49 (couloir reliant le bâtiment 31 au bâtiment 513) dans le cadre du circuit de visites. Ils retracent brièvement l'histoire du Centre de calcul du CERN de la création du laboratoire jusqu'à 2020. Langues : anglais et français.

Related links:
Exhibition area - building 49 - 31 - 513
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2021-01-20
07:35
The track-based alignment of the ALFA Roman Pot detectors of the ATLAS experiment
Reference: ATL-FWD-PUB-2021-003
Note: PUB
Keywords:  ALFA, alignment
Created: 2021. -1 p

ALFA detector is part of the ATLAS Roman Pot detector dedicated to measure protons scattered at very small angles. ALFA aims to study elastic and diffractive events in special runs with reduced luminosity and optimized beam optics. Precision of the measurement depends on the correct positioning of the ALFA detector with respect to the actual beam position. For this purpose track-based procedure is used which utilizes tracks of beam halo and elastic protons collected during physics data taking. This poster presents results of fast and robust alignment of ALFA detectors during LHC Run 2. The alignment constants are used in analysis of diffractive events and also serve as preliminary values in elastic analysis. Precise measurements of the elastic cross sections required dedicated more precise measurement

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2021-01-19
19:50
A study of the proton reconstruction efficiency with the ALFA detector using an overlay technique of Monte Carlo signal events with zero-bias collider data.
Reference: ATL-FWD-PUB-2021-001
Note: PUB
Created: 2021. -mult. p

The purpose of the ATLAS Roman Pot (ARP) detector is to measure protons scattered at very small angles. ARP aims to study elastic and diffractive events, exclusive production and photon induced interactions. In LHC Run 2, ARP participated in the ATLAS high-luminosity data taking. In addition, several special runs with reduced luminosity were taken. Any cross section measurement requires good understanding of the particle reconstruction efficiency. This task is particularly complicated in case of forward protons where actual beam condition is important part of the working environment. Modeling of the very forward region in terms of primary particle flux and inactive material producing secondary particle is generally not precise. An overlay technique of MonteCarlo signal events with zero-bias collider data overcomes these difficulties and may provide better understanding of the proton reconstruction efficiency. Proposed plots present results of the proton reconstruction efficiency with the ALFA detector.

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2021-01-13
16:24
LHCb - X(3872) production in pp with particle multiplicity
Reference: Poster-2021-1042
Created: 2021. -5 p
Creator(s): Epple, Eliane

The last decade of hadron spectroscopy has unveiled a wealth of states that do not have the properties expected of particles composed of 2 or 3 valence quarks. Among the most intriguing of these exotics is the X(3872), which various models attempt to describe as a hadronic molecule, a compact tetraquark, an unexpected charmonium state, or their mixtures. Production in heavy ion collisions, as well as high multiplicity pp collisions, offer a new window on the properties of this poorly understood hadron. In these systems, promptly produced X(3872) hadrons can interact with other particles in the nucleus and/or those produced in the collision. The influence of these interactions on the observed X(3872) yields provides information that can help discriminate between the various models of its structure, as well as give insight into the dynamics of the bulk particles produced in these collisions. With a full range of precision vertexing, tracking, and particle ID capabilities covering 2 to 5 in units of rapidity, the LHCb experiment is especially well suited to measurements of both prompt and non-prompt exotic hadrons.This talk will present new LHCb measurements X(3872) production in highmultiplicity pp collisions through the decay to J/ψπ+π−.

Related links:
Conference, The VI-th International Conference on the Initial Stages of High-Energy Nuclear Collisions
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