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G. A. Stewart

Publications and source records attributed to G. A. Stewart.

5 recordsLinked to original sources
arXiv2023

Training and Onboarding initiatives in High Energy Physics experiments

In this paper we document the current analysis software training and onboarding activities in several High Energy Physics (HEP) experiments: ATLAS, CMS, LHCb, Belle II and DUNE. Fast and efficient onboarding of new collaboration members is increasingly important for HEP experiments as analyses and the related software become ever more complex with growing datasets. A meeting series was held by the HEP Software Foundation (HSF) in 2022 for experiments to showcase their initiatives. Here we document and analyse these in an attempt to determine a set of key considerations for future experiments.

hep-ex↗
arXiv2022

Offloading electromagnetic shower transport to GPUs

Making general particle transport simulation for high-energy physics (HEP) single-instruction-multiple-thread (SIMT) friendly, to take advantage of accelerator hardware, is an important alternative for boosting the throughput of simulation applications. To date, this challenge is not yet resolved, due to difficulties in mapping the complexity of Geant4 components and workflow to the massive parallelism features exposed by graphics processing units (GPU). The AdePT project is one of the R\&D initiatives tackling this limitation and exploring GPUs as potential accelerators for offloading some part of the CPU simulation workload. Our main target is to implement a complete electromagnetic shower demonstrator working on the GPU. The project is the first to create a full prototype of a realistic electron, positron, and gamma electromagnetic shower simulation on GPU, implemented as either a standalone application or as an extension of the standard Geant4 CPU workflow. Our prototype currently provides a platform to explore many optimisations and different approaches. We present the most recent results and initial conclusions of our work, using both a standalone GPU performance analysis and a first implementation of a hybrid workflow based on Geant4 on the CPU and AdePT on the GPU.

hep-ex↗
arXiv2022

Constraints on future analysis metadata systems in High Energy Physics

In High Energy Physics (HEP), analysis metadata comes in many forms -- from theoretical cross-sections, to calibration corrections, to details about file processing. Correctly applying metadata is a crucial and often time-consuming step in an analysis, but designing analysis metadata systems has historically received little direct attention. Among other considerations, an ideal metadata tool should be easy to use by new analysers, should scale to large data volumes and diverse processing paradigms, and should enable future analysis reinterpretation. This document, which is the product of community discussions organised by the HEP Software Foundation, categorises types of metadata by scope and format and gives examples of current metadata solutions. Important design considerations for metadata systems, including sociological factors, analysis preservation efforts, and technical factors, are discussed. A list of best practices and technical requirements for future analysis metadata systems is presented. These best practices could guide the development of a future cross-experimental effort for analysis metadata tools.

hep-ex↗
arXiv2017

Crystal structure and magnetic modulation in beta-Ce2O2FeSe2

We report a combination of X-ray and neutron diffraction studies, Mossbauer spectroscopy and muon spin relaxation (muSR) measurements to probe the structure and magnetic properties of the semiconducting beta-Ce2O2FeSe2 oxychalcogenide. We report a new structural description in space group Pna21 which is consistent with diffraction data and second harmonic generation measurements and reveal an order-disorder transition on one Fe site at TOD ~ 330 K. Susceptibility measurements, Mossbauer and muSR reveal antiferromagnetic ordering below TN = 86 K and more complex short range order above this temperature. 12 K neutron diffraction data reveal a modulated magnetic structure with q = 0.444 bN*.

cond-mat.mtrl-sci↗