bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient synthesis of spirooxindolyl oxazol-2(5H)-ones via palladium(ii)-catalyzed addition of arylboronic acids to nitriles
Authors: Song Hao , Cheng Na , She Li-Qin , Wu Yi , Liao Wei-Wei
Published: September 2019

A versatile synthesis of spirooxindolyl oxazol-2(5H)-ones and derivatives via palladium(ii)-catalyzed addition of arylboronic acids to nitriles is described.
Highly stable one-dimensional Pt nanowires with modulated structural disorder towards the oxygen reduction reaction
Authors: Kong Fanpeng , Norouzi Banis Mohammad , Du Lei , Zhang Lijie , Zhang Lei , Li Junjie , Doyle-Davis Kieran , Liang Jianneng , Liu Qingsong , Yang Xiaofei , Li Ruying , Du Chunyu , Yin Geping , Sun Xueliang
Published: September 2019

Developing stable nanocatalysts with high activity for the oxygen reduction reaction (ORR) remains a great challenge in the field of clean energy.
Utilizing the heterocyclic effect towards high contrast ratios of mechanoresponsive luminescence based on aromatic aldehydes
Authors: Zhang Fang , Liang Xiaozhong , Li Da , Yin Xiangkai , Tian Xia , Li Bin , Xu Hong , Guo Kunpeng , Li Jie
Published: September 2019

Utilizing heterocycles with different-membered rings and additional heteroatoms would be an effective way to increase MRL contrast ratios by tuning different types of noncovalent interactions in the solid state.
Twisted debris: how differential secular perturbations shape debris disks
Authors: Sende J. A. , Löhne T.
Published: September 2019

Context. Resolved images suggest that asymmetric structures are a common feature of cold debris disks. While planets close to these disks are rarely detected, their hidden presence and gravitational perturbations provide plausible explanations for some of these features.

Aims. To put constraints on the properties of yet undetected planetary companions, we aim to predict what features such a planet imprints in debris disks undergoing continuous collisional evolution.

Methods. We discuss the basic equations, analytic approximations and timescales governing collisions, radiation pressure and secular perturbations. In addition, we combine our numerical model of the collisional evolution of the size and spatial distributions in debris disks with the gravitational perturbation by a single planet.

Results. We find that the distributions of orbital elements in the disks are strongly dependent on grain sizes. Secular precession is differential with respect to involved semi-major axes and grain sizes. This leads to observable differences between the big grains tracing the parent belt and the small grains in the trailing halo. Observations at different wavelengths can be used to constrain the properties of a possible planet.
High-resolution three-dimensional simulations of gas removal from ultrafaint dwarf galaxies
Authors: Romano Donatella , Calura Francesco , D’Ercole Annibale , Few C. Gareth
Published: September 2019

Context.The faintest Local Group galaxies found lurking in and around the Milky Way halo provide a unique test bed for theories of structure formation and evolution on small scales. Deep Subaru andHubbleSpace Telescope photometry demonstrates that the stellar populations of these galaxies are old and that the star formation activity did not last longer than 2 Gyr in these systems. A few mechanisms that may lead to such a rapid quenching have been investigated by means of hydrodynamic simulations, but these have not provided any final assessment so far.

Aims.This is the first in a series of papers aimed at analyzing the roles of stellar feedback, ram pressure stripping, host-satellite tidal interactions, and reionization in cleaning the lowest mass Milky Way companions of their cold gas using high-resolution, three-dimensional hydrodynamic simulations.

Methods.We simulated an isolated ultrafaint dwarf galaxy loosely modeled after Boötes I, and examined whether or not stellar feedback alone could drive a substantial fraction of the ambient gas out from the shallow potential well.

Results.In contrast to simple analytical estimates, but in agreement with previous hydrodynamical studies, we find that most of the cold gas reservoir is retained. Conversely, a significant amount of the metal-enriched stellar ejecta crosses the boundaries of the computational box with velocities exceeding the local escape velocity and is, thus, likely lost from the system.

Conclusions.Although the total energy output from multiple supernova explosions exceeds the binding energy of the gas, no galactic-scale outflow develops in our simulations and as such, most of the ambient medium remains trapped within the weak potential well of the model galaxy. It seems thus unavoidable that to explain the dearth of gas in ultrafaint dwarf galaxies, we will have to resort to environmental effects. This will be the subject of a forthcoming paper.
Interstellar dust along the line of sight of GX 3+1
Authors: Rogantini D. , Costantini E. , Zeegers S. T. , de Vries C. P. , Mehdipour M. , de Groot F. , Mutschke H. , Psaradaki I. , Waters L. B. F. M.
Published: September 2019

Context.Studying absorption and scattering of X-ray radiation by interstellar dust grains allows us to access the physical and chemical properties of cosmic grains even in the densest regions of the Galaxy.

Aims.We aim at characterising the dust silicate population which presents clear absorption features in the energy band covered by theChandraX-ray Observatory. Through these absorption features, in principle, it is possible to infer the size distribution, composition, and structure of silicate in the interstellar medium. In particular, in this work we investigate magnesium and silicon K-edges.

Methods.We built X-ray extinction models for 15 dust candidates using newly acquired synchrotron measurements. These models were adapted for astrophysical analysis and implemented in the SPEXspectral fitting program. We used the models to reproduce the dust absorption features observed in the spectrum of the bright low mass X-ray binary GX 3+1, which is used as a background source.

Results.With the simultaneous analysis of the two edges we test two different size distributions of dust: one corresponding to the standard Mathis-Rumpl-Nordsieck model and one considering larger grains (n(a) ∝ai−3.5with 0.005μm <a1< 0.25μm and 0.05μm <a2< 0.5μm, respectively, withathe grain size). These distributions may be representative of the complex Galactic region towards this source. We find that up to 70% of dust is constituted by amorphous olivine. We discuss the crystallinity of the cosmic dust found along this line of sight. Both magnesium and silicon are highly depleted into dust (δZ= 0.89 and 0.94, respectively), while their total abundance does not depart from solar values.
Formation of coronal rain triggered by impulsive heating associated with magnetic reconnection
Authors: Kohutova P. , Verwichte E. , Froment C.
Published: September 2019

Context. Coronal rain consists of cool plasma condensations formed in coronal loops as a result of thermal instability. The standard models of coronal rain formation assume that the heating is quasi-steady and localised at the coronal loop footpoints.

Aims. We present an observation of magnetic reconnection in the corona and the associated impulsive heating triggering formation of coronal rain condensations.

Methods. We analyse combined SDO/AIA and IRIS observations of a coronal rain event following a reconnection between threads of a low-lying prominence flux rope and surrounding coronal field lines.

Results. The reconnection of the twisted flux rope and open field lines leads to a release of magnetic twist. Evolution of the emission of one of the coronal loops involved in the reconnection process in different AIA bandpasses suggests that the loop becomes thermally unstable and is subject to the formation of coronal rain condensations following the reconnection and that the associated heating is localised in the upper part of the loop leg.

Conclusions. In addition to the standard models of thermally unstable coronal loops with heating localised exclusively in the footpoints, thermal instability and subsequent formation of condensations can be triggered by the impulsive heating associated with magnetic reconnection occurring anywhere along a magnetic field line.
Simultaneous usage of the LHCb HLT farm for Online and Offline processing workflows
Authors: Closier Joel , Gaspar Clara , Granado Cardoso Luis , Haen Christophe , Jost Beat , Neufeld Niko
Published: September 2019

LHCb is one of the 4 LHC experiments and continues to revolutionise data acquisition and analysis techniques. Already two years ago the concepts of “online” and “offline” analysis were unified: the calibration and alignment processes take place automatically in real time and are used in the triggering process such that Online data are immediately available offline for physics analysis (Turbo analysis), the computing capacity of the HLT farm has been used simultaneously for different workflows : synchronous first level trigger, asynchronous second level trigger, and Monte-Carlo simulation. Thanks to the same software environment, LHCb can switch seamlessly and fast from Online to Offline workflows, run them simultaneously and thus maximize the usage of the HLT farm computing resources.
Open-Hardware and Application Specific Design for the Monitoring System of the Belle II Forward/Backward Electromagnetic Calorimeter
Authors: Di Capua Francesco , Aloisio Alberto , Ameli Fabrizio , Anastasio Antonio , Branchini Paolo , Giordano Raffaele , Izzo Vincenzo , Tortone Gennaro
Published: September 2019

Control and monitoring of experimental facilities as well as laboratory equipment requires handling a blend of different tasks. Often in industrial or scientific fields there are standards or form factor to comply with and electronic interfaces or custom busses to adopt. With such tight boundary conditions, the integration of an off-the-shelf Single Board Computer (SBC) is not always a possible or viable alternative. The availability of electronic schematics and PCBs with open-source Hardware license for various SBCs overcomes such integration problems, making feasible the implementation of a custom architecture composed by a central core inherited from a vendor reference design (most likely the microprocessor, static RAM and flash memory) augmented with application-specific integrated circuits and hardware resources, in order to handle the requirements of the specific environment. The user is then able to exploit most of the supported tools and software provided by opensource community, fulfilling all the constraints enforced by his environment. We have used such an approach for the design and development of the monitoring system of the endcap electromagnetic calorimeter of the Belle II experiment, presently running at KEK Laboratory (Tsukuba, Japan). Here we present and discuss the main aspects of the hardware architectures and noise performances tailored on the needs of a detector designed around CsI crystal scintillators.
Particle Flow reconstruction in the CMS Level-1 Trigger For The HL-LHC
Authors: Petrucciani Giovanni
Published: September 2019

With the planned addition of the tracking information in the Level-1 trigger in CMS for the High-Luminosity Large Hadron Collider (HL-LHC), the algorithms for the Level-1 trigger can be completely reconceptualized. Following the example for offline reconstruction in CMS to use complementary subsystem information and mitigate pileup, we explore the feasibility of using Particle Flow-like and pileup-per-particle identification techniques at the hardware trigger level. We present the challenges of adapting these algorithm to the timing and resource constraints of the Level-1 trigger, the first prototype implementations, and the expected performance on physics object reconstruction.
The SLAC RCE Platform for ProtoDUNE
Authors: Tsang K.V. , Convery M. , Graham M. , Herbst R. , Russell J.
Published: September 2019

The ProtoDUNE-SP is a single-phase liquid argon time projection chamber (LArTPC) prototype for the Deep Underground Neutrino Experiment (DUNE). Signals from 15,360 electronic channels are received by 60 Reconfigurable Cluster Elements (RCEs), which are processing elements designed at SLAC for a wide range of applications and are based upon the “system-onchip” Xilinx Zynq family of FPGAs. The RCEs are housed in industry-standard ATCA shelves on a custom blade, called the Cluster on Board (COB). The RCE platform and its processing functions for the ProtoDUNE-SP will be presented.
Towards The Alice Online-Offline (O2) Control System
Authors: Mrnjavac Teo , Chibante Barroso Vasco
Published: September 2019

The ALICE Experiment at CERN LHC (Large Hadron Collider) is under preparation for a major upgrade that is scheduled to be deployed during Long Shutdown 2 in 2019-2020 and that includes new computing systems, called O2 (Online-Offine). To ensure the efficient operation of the upgraded experiment along with its newly designed computing system, a reliable, high performance and automated control system will be developed with the goal of managingthe lifetime of all the O2 processes, and of handling the various phases of the data taking activity by interacting with the detectors, the trigger system and the LHC. The ALICE O2 control system will be a distributed systembased on state of the art cluster management and microservices which have recently emerged in the distributed computing ecosystem. Such technologies weren’t available during the design and development of the original LHC computing systems, and their use will allow the ALICE collaboration to benefit from a vibrant and innovatingopen source community. This paper illustrates the O2 control system architecture. It evaluates several olutionsthat were considered during an initial prototyping phase and provides a rationale for the choices made. It also provides an in-depth overview of the components, features and design elements of the actual system.
Software-based data acquisition system for Level-1 end-cap muon trigger in Atlas Run-3
Authors: Takeda Kosuke
Published: September 2019

In 2019, the ATLAS experiment at CERN is planning an upgrade in order to cope with the higher luminosity requirements. In this upgrade, the installation of the new muon chambers for the end-cap muon system will be carriedout. Muon track reconstruction performance can be improved, and fake triggers can be reduced. It is also necessary to develop readout system of trigger data for the Level-1 end-cap muon trigger.

We have decided to develop software-based data acquisition system. There-fore, we have implemented SiTCP technology, which connects a FPGA with the network, on the FPGA of new trigger processor boards.

Due to this implementation, the new DAQ system can take advantage of the latest developments in computing industry. This new readout system architec-ture is based on multi-process software, and can assemble events at a rate of 100 kHz. For data collection, the 10 Gbit Ethernet network switch is used. Moreover, we have optimized these processes to send data to the following sys-tem without any error. Therefore, the built events can be sent with an average throughput of approximately 211 Mbps.

Our newly developed readout system is very generic and it is flexible for modi-fications, extensions and easyto debug. This paper will present the details of the new software-based DAQ system and report the development status for ATLAS Run-3.
New approaches for track reconstruction in LHCb’s Vertex Locator
Authors: Albrecht Johannes , Bourgeois Dylan , Coco Victor , Couturier Ben , Hasse Christoph , Nolte Niklas , Ponce Sebastien
Published: September 2019

Starting with Upgrade 1 in 2021, LHCb will move to a purely software-based trigger system. Therefore, the new trigger strategy is to process events at the full rate of 30MHz. Given that the increase of CPU performance
has slowed down in recent years, the predicted performance of the software trigger currently falls short of the necessary 30MHz throughput. To cope with this shortfall, the Upgrade High Level Trigger currently uses impact parameter cuts on VELO tracks to reduce the amount of tracks which require further processing. The presented work introduces an alternative approach to determine the impact parameter while achieving a more reliable uncertainty prediction than the current method, which could potentially improve the physics quality of these cuts at a later time.
Cms Ecal Daq Monitoring System
Authors: Cucciati Giacomo
Published: September 2019

The Large Hadron Collider (LHC) at CERN in Geneva, Switzerland, has just completed the Run 2 era, colliding protons at a center-of-mass energy of 13 TeV at high instantaneous luminosity. The Compact Muon Solenoid (CMS) is a general-purpose particle detector experiment at the LHC. The CMS electromagnetic calorimeter (ECAL) has been designed to achieve excellent energy and position resolution for electrons and photons. A multi-machine distributed software configures the on-detector and off-detector electronic boards composing the ECAL data acquisition (DAQ) system and follows the life cycle of the acquisition process. Since the beginning of Run 2 in 2015, many improvements to the ECAL DAQ have been implemented to reduce and mitigate occasional errors in the front-end electronics and not only. Efforts at the software level have been made to introduce automatic recovery in case of errors. Automatic actions has made even more important the online monitoring of the DAQ boards status. For this purpose a new web application, EcalView, has been developed. It runs on a light Node.js JavaScript server framework. It is composed of several routines that cyclically collect the status of the electronics. It display the information when web requests are launched by client side graphical interfaces. For each board, detailed information can be loaded and presented in specific pages if requested by the expert. Server side routines store information regarding electronics errors in a SQLite database in order to perform offline analysis about the long term status of the boards.
Trigger Rate Monitoring Tools at CMS
Authors: Wightman Andrew , Smith Geoffrey , Mohrman Kelci , Mueller Charles
Published: September 2019

One of the major challenges for the Compact Muon Solenoid (CMS)experiment, is the task of reducing event rate from roughly 40 MHz down to a more manageable 1 kHz while keeping as many interesting physics events as possible. This is accomplished through the use of a Level-1 (L1) hardware based trigger as well as a software based High-Level Trigger (HLT). Monitoring and understanding the output rates of the L1 and HLT triggers is of key importance for determining the overall performance of the trigger system and is intimately tied to what type of data is being recorded for physics analyses. We present here a collection of tools used by CMS to monitor the L1 and HLT trigger rates. One of these tools is a script (run in the CMS control room) that gives valuable real-time feedback of trigger rates to the shift crew. Another useful tool is a plotting library, that is used for observing how trigger rates vary over a range of beam and detector conditions, in particular how the rates of individual triggers scale with event pile-up.
The design and Performance of the Atlas Inner Detector Trigger in High Pileup Collisions at 13 Tev at the Large Hadron Collider
Authors: Kirk Julie
Published: September 2019

The design and performance of the ATLAS Inner Detector (ID) trigger algorithms running online on the High Level Trigger (HLT) processor farm for 13 TeV LHC collision data with high pileup are discussed. The HLT ID tracking is a vital component in all physics signatures in the ATLAS trigger for the precise selection of the rare or interesting events necessary for physics analysis without overwhelming the offline data storage in terms of both size and rate. To cope with the high interaction rates expected in the 13 TeV LHC collisions, the ID trigger was redesigned during the 2013-15 long shutdown. The performance of the ID trigger in Run 2 data from 13 TeV LHC collisions has been excellent and exceeded expectations, even at the very high interaction multiplicities observed at the end of data-taking in 2017. The detailed efficiencies and resolutions of the ID trigger in a wide range of physics signatures are presented for the Run 2 data. The superb performance of the ID trigger algorithms in these extreme pileup conditions demonstrates how the ID tracking continues to lie at the heart of the trigger performance to enable the ATLAS physics program, and will continue to do so in the future.
Highly Extensible Modular System for Online Monitoring of the Atlas Experiment
Authors: Kolos Serguei
Published: September 2019

The unprecedented size and complexity of the ATLAS experiment required adoption of a new approach for online monitoring system development as many requirements for this system were not known in advance due to the innovative nature of the project. The ATLAS online monitoring facility has been designed as a modular system consisting of a number of independent components, which can interact with one another via a set of well-defined interfaces. The system has been developed using open source software and is based on the two in-house developed highly scalable distributed services for message passing and information exchange, which can deal with information of arbitrary types. The other monitoring components use these services to implement high-level facilities, such as Monitoring Data Archiving and Data Quality Assessment, as well as end user interfaces like the Data Quality and Online Histogramming displays. This proceedings describes the online monitoring system design and evolution showing how the chosen approach allowed the system to be gradually extended by adding more high level tools and frameworks as requirements evolved.
3D convolutional GAN for fast simulation
Authors: Vallecorsa Sofia , Carminati Federico , Khattak Gulrukh
Published: September 2019

Machine Learning techniques have been used in different applications by the HEP community: in this talk, we discuss the case of detector simulation. The need for simulated events, expected in the future for LHC experiments and their High Luminosity upgrades, is increasing dramatically and requires new fast simulation solutions. We describe an R&D activity aimed at providing a configurable tool capable of training a neural network to reproduce the detector response and speed-up standard Monte Carlo simulation. This represents a generic approach in the sense that such a network could be designed and trained to simulate any kind of detector and, eventually, the whole data processing chain in order to get, directly in one step, the final reconstructed quantities, in just a small fraction of time. We present the first application of three-dimensional convolutional Generative Adversarial Networks to the simulation of high granularity electromagnetic calorimeters. We describe detailed validation studies comparing our results to Geant4 Monte Carlo simulation. Finally we show how this tool could be generalized to describe a whole class of calorimeters, opening the way to a generic machine learning based fast simulation approach.
Virtual Reality and game engines for interactive data visualization
and event displays in HEP, an example from the ATLAS experiment
Authors: Riccardo Maria Bianchi , Adam Bourdarios Claire , Hovdesven Michael , Vukotic Ilija
Published: September 2019

Interactive 3D data visualization plays a key role in HEP experiments, as it is used in many tasks at different levels of the data chain. Outside HEP, for interactive 3D graphics, the game industry makes heavy use of so-called “game engines”, modern software frameworks offering an extensive set of powerful graphics tools and cross-platform deployment. Recently, a very strong support for Virtual Reality (VR) technology has been added to such engines. In this talk we explore the usage of game engines and VR for HEP data visualization, discussing the needs, the challenges and the issues of using such technologies. We will also make use of ATLASrift, a VR application developed by the ATLAS experiment, to discuss the lessons learned while developing it using the game engine Unreal Engine, and the feedback on the use of Virtual Reality we got from users while using it at many demonstrations and public events.
Tracking system performance of the BM@N experiment
Authors: Kapishin Mikhail , Lenivenko Vasilisa , Palichik Vladimir , Pokatashkin Gleb , Rufanov Igor , Vasendina Veronika , Voytishin Nikolay , Zinchenko Alexander
Published: September 2019

The Baryonic Matter at Nuclotron (BM@N) experiment represents the first phase of the Nuclotron-based Ion Collider Facility (NICA), a mega-science project at the Joint Institute for Nuclear Research. It is a fixed target experiment built for studying nuclear matter in conditions of extreme density and temperature. The tracking system of the BM@N experiment consists of three main detector systems: Multiwire Proportional Chambers situated before the magnet, Gas Electron Multipliers placed inside the magnet and Drift Chambers placed after the magnet. These systems provide the reconstruction of charged particles’ trajectories and their momentum in the magnetic field. This information is further used by Time of Flight detectors for the particle identification procedure. The system’s performance is reviewed and the spatial resolutions along with efficiencies of the detectors are estimated using the data collected in the recent physics runs of the Nuclotron.
Perspectives for the migration of the LHCb geometry to the DD4hep toolkit
Authors: Borghi Silvia , Burr Chris , Clemencic Marco , Corti Gloria , Couturier Ben , Frank Markus , Grillo Lucia , Muller Dominik
Published: September 2019

The LHCb experiment uses a custom made C++ detector and geometry description toolkit, integrated with the Gaudi framework, designed when the LHCb software was first implemented. With the LHCb upgrade scheduled for 2021, it is necessary for the experiment to review this choice and adapt to the evolution of software and computing (in terms of e.g multi-threading support or vectorization)

The Detector Description Toolkit for High Energy Physics (DD4hep) is a good candidate for the replacement for LHCb’s geometry description framework: it is possible to integrate it with the LHCb core software framework and its features theoretically match the requirements: in terms of geometry and detector description but also concerning the possibility to add detector alignment parameters and the integration with simulation tools.

In this paper we report on detailed studies undertaken to compare the feature set proposed by the DD4hep toolkit, to what is needed by LHCb. We show not only how the main description could be migrated, but also how to integrate the LHCb real-time alignment tools in this toolkit, in order to identify the main obstacles to the migration of the experiment to DD4hep.
DyTER – Dynamic Track and Event Reconstruction
Authors: Papenbrock Michael
Published: September 2019

The future PANDA experiment at FAIR experiment aims to cover a wide range of processes in antiproton-proton collisions at event rates of up to 20 MHz. Such event rates make reconstruction a challenging task for the purely software-based event filter. Investigating complex event topologies with displaced vertices increases the difficulty even further. Here we present two attempts to meet these future challenges: an algorithm for track reconstruction based on pattern matching with pre-determined look-up tables, and as a continuation of this approach a system of neural networks for identifying specific particle track candidates and predicting their momentum.
Experience of the Development of the Geometry Database for the CBM Experiment
Authors: Akishina Elena , Alexandrov Evgeny , Alexandrov Igor , Filozova Irina , Friese Volker , Ivanov Victor
Published: September 2019

This paper is dedicated to the current state of the Geometry Database (Geometry DB) for the CBM experiment. The geometry DB is an information system that supports the CBM geometry. The main aims of Geometry DB are to provide storage of the CBM geometry, convenient tools for managing the geometry modules, assembling various versions of the CBM setup as a combination of geometry modules and additional files, providing support of various versions of the CBM setup. The development is based on the analysed users’ requirements (which were formulated in User Requirements Document) and takes into account peculiarities of the workflow for simulation of particle transport through the setup. Both the Graphical User Interface (GUI) and the Application Programming Interface (API) are available for the members of the CBM collaboration.
A High-Precision Tracking Algorithm for Mass Reconstruction of Heavy-Ion Fragments in the R3B Experiment at FAIR
Authors: Kresan Dmytro , Heil Michael , Al-Turany Mohammad
Published: September 2019

The multi-purpose R3B (Reactions with Relativistic Radioactive Beams) setup at the future FAIR facility in Darmstadt will be used for various experiments with exotic beams in inverse kinematics. In front and after the reaction target a combination of detectors serves for particle identification and momentum measurements. In order to perform a high-precision charge identification of heavy-ion fragments and achieve a momentum resolution of 10-3 following is required: a time of flight (ToF) measurement with up to 15 ps accuracy, position determination on the order of less than 0.5 mm and a dedicated algorithm for the heavy-ion tracking in highly non-homogeneous dipole field. With these constraints a tracking package is being developed and tested within the R3B software framework, this package has to go into production in fall of 2018. An iterative approach has been chosen for simultaneous track finding and fitting. The design and concept of the package are introduced in this paper, also the tests and the resolution measured with simulated data are presented.
Upgrade of ATLAS data quality monitoring for multithreaded reconstruction
Authors: Bold Tomasz , Lampl Walter , Narayan Rohin , Onyisi Peter , Sarna Piotr
Published: September 2019

ATLAS is embarking on a project to multithread its reconstruction software in time for use in Run 3 of the LHC. One component that must be migrated is the histogramming infrastructure used for data quality monitoring of the reconstructed data. This poses unique challenges due to its large memory footprint which forms a bottleneck for parallelization and the need to accommodate relatively inexperienced developers. We discuss plans for the upgraded framework.
Advances in ATLAS@Home towards a major ATLAS computing resource
Authors: Cameron David , Wu Wenjing , Bogdanchikov Alexander , Bianchi Riccardo
Published: September 2019

The volunteer computing project ATLAS@Home has been providing a stable computing resource for the ATLAS experiment since 2013. It has recently undergone some significant developments and as a result has become one of the largest resources contributing to ATLAS computing, by expanding its scope beyond traditional volunteers and into exploitation of idle computing power in ATLAS data centres. Removing the need for virtualization on Linux and instead using container technology has made the entry barrier significantly lower for data centre participation and in this paper, we describe the implementation and results of this change. We also present other recent changes and improvements in the project. In early 2017 the ATLAS@Home project was merged into a combined LHC@Home platform, providing a unified gateway to all CERN-related volunteer computing projects. The ATLAS Event Service shifts data processing from file-level to event-level and we describe how ATLAS@Home was incorporated into this new paradigm.
Extending CERN computing to volunteers - LHC@home consolidation and outlook
Authors: Cameron David , Field Laurence , Giannakis Nikolas , Høimyr Nils
Published: September 2019

LHC@home has provided computing capacity for simulations under BOINC since 2005. Following the introduction of virtualisation with BOINC to run HEP Linux software in a virtual machine on volunteer desktops, initially started on test BOINC projects, like Test4Theory and ATLAS@home, all CERN applications distributed to volunteers have been consolidated under a single LHC@home BOINC project. As part of an effort to unite CERN’s batch, cloud, grid and volunteer computing efforts, the BOINC service has been integrated with the other compute services at CERN, notably HTCondor, in terms job submission and accounting. The paper will also address contributions to improve the BOINC software and community effort to evolve BOINC for a sustainable volunteer computing environment. Furthermore, we discuss future challenges to reduce the effort required by volunteers to run virtual machines for experiment simulations and improvements to BOINC to widen the appeal of volunteer computing.
Understanding the evolution of conditions data access through Frontier for the ATLAS Experiment
Authors: Svatos Michal , De Salvo Alessandro , Dewhurst Alastair , Vamvakopoulos Emmanouil , Lozano Bahilo Julio , Ozturk Nurcan , Sanchez Javier , Dykstra Dave
Published: September 2019

The ATLAS Distributed Computing system uses the Frontier system to access the Conditions, Trigger, and Geometry database data stored in the Oracle Offline Database at CERN by means of the HTTP protocol. All ATLAS computing sites use Squid web proxies to cache the data, greatly reducing the load on the Frontier servers and the databases. One feature of the Frontier client is that in the event of failure, it retries with different services. While this allows transient errors and scheduled maintenance to happen transparently, it does open the system up to cascading failures if the load is high enough. Throughout LHC Run 2 there has been an ever increasing demand on the Frontier service. There have been multiple incidents where parts of the service failed due to high load. A significant improvement in the monitoring of the Frontier service wasrequired. The monitoring was needed to identify both problematic tasks, which could then be killed or throttled, and to identify failing site services as the consequence of a cascading failure is much higher. This presentation describes the implementation and features of the monitoring system.
Production experience and performance for ATLAS data processing on a Cray XC-50 at CSCS
Authors: Sciacca F G , Weber M
Published: September 2019

Prediction for requirements for the LHC computing for Run 3 and for Run 4 (HL-LHC) over the course of the next 10 year, show a considerable gap between required and available resources, assuming budgets will globally remain flat at best. This will require some radical changes to the computing models for the data processing of the LHC experiments. The use of large scale computational resources at HPC centres worldwide is expected to increase substantially the cost-efficiency of the processing. In order to pave the path towards the HL-LHC data processing, the Swiss Institute of Particle Physics (CHIPP) has taken the strategic decision to migrate the processing of all the Tier-2 workloads for ATLAS and other LHC experiments from a dedicated x86 ̲ 64 cluster that has been in continuous operation and evolution since 2007, to Piz Daint, the current European flagship HPC, which ranks third in the TOP500 at the time of writing. We report on the technical challenges and solutions adopted to migrate to Piz Daint, and on the experience and measured performance for ATLAS in over one year of running in production.
FERRY: access control and quota management service
Authors: Altunay Mine , Boyd Joseph , Coimbra Bruno , Herner Kenneth , Jacobs Krysia , Kahn Farrukh , Levshina Tanya , McKittrick Brian , Scott Rennie , Skirvin Timothy , Stores Felix , Teheran Jeny , Votava Margaret , Whited Tammy
Published: September 2019

Fermilab developed the Frontier Experiments RegistRY (FERRY) service that provides a centralized repository for access control and job management attributes such as batch and storage access policies, quotas, batch priorities and NIS attributes for cluster configuration. This paper describes the FERRY architecture, deployment and integration with services that consume the stored information. The Grid community has developed several access control management services over the last decade. Over time, services for Fermilab experiments have required the collection and management of more access control and quota attributes. At the same time, various services used for this purpose, namely VOMS-Admin, GUMS and VULCAN, are being abandoned by the community. FERRY has multiple goals: maintaining a central repository for currently scattered information related to users' attributes, providing a Restful API that allows uniform data retrieval by services, and providing a replacement service for all the abandoned grid services. FERRY is integrated with the ServiceNow (SNOW) ticketing service and uses it as its user interface. In addition to the standard workflows for request approval and task creation, SNOW invokes orchestration that automates access to FERRY API. Our expectation is that FERRY will drastically improve user experience as well as decrease effort required by service administrators.
Deploying and extending CMS Tier 3s using VC3 and the OSG Hosted CE service
Authors: Hurtado Anampa Kenyi , Lannon Kevin , Thain Douglas , Tovar Ben
Published: September 2019

CMS Tier 3 centers, frequently located at universities, play an important role in the physics analysis of CMS data. Although different computing resources are often available at universities, meeting all requirements to deploy a valid Tier 3 able to run CMS workflows can be challenging in certain scenarios. For instance, providing the right operating system (OS)with access to the CERNVM File System (CVMFS) on the worker nodes or having a Compute Element (CE) on the submit host is not always allowed or possible due to e.g: lack of root access to the nodes, TCP port network policies, maintenance of a C,etc. The Notre Dame group operates a CMS Tier 3 with 1K cores. In addition to this, researchers have access to an opportunistic pool with +25K cores that are used via lobster for CMS jobs, but cannot be used with other standard CMS submission tools on the grid like CRAB, as these resources are not part of the Tier 3 due to its opportunistic nature. This work describes the use of VC3, a service for automating the deployment of virtual cluster infrastructures, in order to provide the environment (user-space CVMFS access and customized OS via singularity containers) needed for CMS workflows to work. Also, we describe its integration with the OSG Hosted CE service, to add these resources to CMS as part of our existing Tier 3 in a seamless way.
Federated Identity Management for Research
Authors: Barton Thomas , Gietz Peter , Kelsey David , Koranda Scott , Short Hannah , Stevanovic Uros
Published: September 2019

Federated identity management (FIM) is an arrangement that can be made among multiple organisations that lets subscribers use the same identification data to obtain access to the secured resources of all organisations in the group. In many research communities there is an increasing interest in a common approach to FIM as there is obviously a large potential for synergies. FIM4R [1] provides a forum for communities to share challenges and ideas, and to shape the future of FIM for our researchers. Current participation covers high energy physics, life sciences and humanities, to mention but a few. In 2012 FIM4R converged on a common vision for FIM, enumerated a set of requirements and proposed a number of recommendationsfor ensuring a roadmap for the uptake of FIM [2]. In summer 2018, FIM4R published an updated version of this paper [3]. The High Energy Physics (HEP) Community has been heavily involved in creating both the original white paper and the new version, which documented the progress made in FIM for Research, in addition to the current challenges. This paper presents the conclusions of this second FIM4R white paper and a summary of the identified requirements and recommendations. We focus particularly on the direction being taken by the Worldwide LHC Computing Grid (WLCG), through the WLCG Authorisation Working Group, and the requirements gathered from the HEP Community.
The LZ UK Data Centre
Authors: Bauer Daniela , Colling David , Fayer Simon , Korolkova Elena , Richards Alexander , Vacheret Antonin
Published: September 2019

LUX-ZEPLIN (LZ) is a Dark Matter experiment based at the Sanford Underground Research Facility in South Dakota, USA. It is currently under construction and aims to start data taking in 2020. Its computing model stipulates two independent data centres, one in the USA and one in the UK. Both data centres will hold a complete copy of the experiment’s data and are expected to handle all aspects of data processing and user analysis. Here we discuss the set-up of the UK data centre within the context of the existing UK Grid infrastructure and show that a mature distributed computing system such as the Grid can be extended to serve as a central data centre for a reasonably large non-LHC experiment.
Advances and enhancements in the FabrIc for Frontier Experiments project at Fermilab
Authors: Herner Kenneth , Alba Hernandez Andres Felipe , Bhat Shreyas , Box Dennis , Boyd Joeseph , Coimbra Bruno , Di Benedetto Vito , Ding Pengfei , Dykstra Dave , Fattoruso Michele , Giacchetti Lisa , Kirby Michael , Levshina Tanya , Mazzacane Anna , Mengel Marc , Mhashilkar Parag , Kuropatkin Nikolay , Podstavkov Vladimir , Retzke Kevin , Teheran Jeny
Published: September 2019

The FabrIc for Frontier Experiments (FIFE) project within the Fermilab Scientific Computing Division is charged with integrating offline computing components into a common computing stack for the non-LHC Fermilab experiments, supporting experiment offline computing, and consulting on new, novel workflows. We will discuss the general FIFE onboarding strategy, the upgrades and enhancements in the FIFE toolset, and plans for the coming year. These enhancements include: expansion of opportunistic computing resources (including GPU and high-performance computing resources) available to experiments; assistance with commissioning computing resources at European sites for individual experiments; StashCache repositories for experiments; enhanced job monitoring tools; and a custom workflow management service. Additionally we have completed the first phase of a Federated Identity Management system to make it easier for FIFE users to access Fermilab computing resources.
Caching technologies for Tier-2 sites: A UK perspective
Authors: Skipsey Samuel Cadellin , Brew Chris , Forti Alessandra , Traynor Dan , Li Teng , Boutcher Adam , Roy Gareth , Stewart Gordon , Britton David
Published: September 2019

Pressures from both WLCG VOs and externalities have led to a desire to "simplify" data access and handling for Tier-2 resources across the Grid. This has mostly been imagined in terms of reducing book-keeping for VOs, and total replicas needed across sites. One common direction of motion is to increasing the amount of remote-access to data for jobs, which is also seen as enabling the development of administratively-cheaper Tier-2 subcat-egories, reducing manpower and equipment costs. Caching technologies are often seen as a "cheap" way to ameliorate the increased latency (and decreased bandwidth) introduced by ubiquitous remote-access approaches, but the usefulness of caches is strongly dependant on the reuse of the data thus cached. We report on work done in the UK at four GridPP Tier-2 sites - ECDF, Glasgow, RALPP and Durham - to investigate the suitability of transparent caching via the recently-rebranded XCache (Xrootd Proxy Cache) for both ATLAS and CMS workloads, and to support workloads by other caching approaches (such as the ARC CE Cache).
Distributed Data Collection for the Next Generation ATLAS EventIndex Project
Authors: Fernández Casaní Álvaro , Barberis Dario , Sánchez Javier , García Montoro Carlos , González de la Hoz Santiago , Salt Jose
Published: September 2019

The ATLAS EventIndex currently runs in production in order to build a complete catalogue of events for experiments with large amounts of data. The current approach is to index all final produced data files at CERN Tier0, and at hundreds of grid sites, with a distributed data collection architecture using Object Stores to temporarily maintain the conveyed information, with references to them sent with a Messaging System. The final backend of all the indexed data is a central Hadoop infrastructure at CERN; an Oracle relational database is used for faster access to a subset of this information. In the future of ATLAS, instead of files, the event should be the atomic information unit for metadata, in order to accommodate future data processing and storage technologies. Files will no longer be static quantities, possibly dynamically aggregating data, and also allowing event-level granularity processing in heavily parallel computing environments. It also simplifies the handling of loss and or extension of data. In this sense the EventIndex may evolve towards a generalized whiteboard, with the ability to build collections and virtual datasets for end users. This proceedings describes the current Distributed Data Collection Architecture of the ATLAS EventIndex project, with details of the Producer, Consumer and Supervisor entities, and the protocol and information temporarily stored in the ObjectStore. It also shows the data flow rates and performance achieved since the new Object Store as temporary store approach was put in production in July 2017. We review the challenges imposed by the expected increasing rates that will reach 35 billion new real events per year in Run 3, and 100 billion new real events per year in Run 4. For simulated events the numbers are even higher, with 100 billion events/year in run 3, and 300 billion events/year in run 4. We also outline the challenges we face in order to accommodate future use cases in the EventIndex.
A milestone for DPM (Disk Pool Manager)
Authors: Furano Fabrizio , Oliver Keeble Nurcan , Manzi Andrea , Bitzes Georgios
Published: September 2019

The DPM (Disk Pool Manager) system is a multiprotocol scalable technology for Grid storage that supports about 130 sites for a total of about 90 Petabytes online.

The system has recently completed the development phase that had been announced in the past years, which consolidates its core component (DOME: Disk Operations Management Engine) as a full-featured high performance engine that can also be operated with standardWeb clients and uses a fully documented REST-based protocol.

Together with a general improvement on performance and with a comprehensive administration command-line interface, this milestone also brings back features like the automatic disk server status detection and the volatile pools for deploying experimental disk caches.

In this contribution we also discuss the end of support for the historical DPM components (that also include a dependency on the Globus toolkit), whose deployment is now only linked to the usage of the SRM protocols, hence can be uninstalled when these are not needed any more by the site.