arXiv subjects

D. C. Craik

Publications and source records attributed to D. C. Craik.

3 recordsLinked to original sources

arXiv2022

A Comparison of CPU and GPU implementations for the LHCb Experiment Run 3 Trigger

The LHCb experiment at CERN is undergoing an upgrade in preparation for the Run 3 data taking period of the LHC. As part of this upgrade the trigger is moving to a fully software implementation operating at the LHC bunch crossing rate. We present an evaluation of a CPU-based and a GPU-based implementation of the first stage of the High Level Trigger. After a detailed comparison both options are found to be viable. This document summarizes the performance and implementation details of these options, the outcome of which has led to the choice of the GPU-based implementation as the baseline.

physics.ins-det↗

arXiv2020

Allen: A high level trigger on GPUs for LHCb

We describe a fully GPU-based implementation of the first level trigger for the upgrade of the LHCb detector, due to start data taking in 2021. We demonstrate that our implementation, named Allen, can process the 40 Tbit/s data rate of the upgraded LHCb detector and perform a wide variety of pattern recognition tasks. These include finding the trajectories of charged particles, finding proton-proton collision points, identifying particles as hadrons or muons, and finding the displaced decay vertices of long-lived particles. We further demonstrate that Allen can be implemented in around 500 scientific or consumer GPU cards, that it is not I/O bound, and can be operated at the full LHC collision rate of 30 MHz. Allen is the first complete high-throughput GPU trigger proposed for a HEP experiment.

physics.ins-det↗

arXiv2017

RapidSim: an application for the fast simulation of heavy-quark hadron decays

RapidSim is a lightweight application for the fast simulation of phase space decays of beauty and charm quark hadrons, allowing for quick studies of the properties of signal and background decays in particle physics analyses. Based upon the TGenPhaseSpace class from the ROOT application it uses externally provided fixed-order next-to-leading-logarithm calculations to boost the initial beauty and charm hadrons to the appropriate energy for the production environment of interest. User-defined momentum resolution functions can be used to mimic the effect of imperfect track reconstruction. User-defined efficiency shapes can be applied during generation to reproduce the effects of geometric and kinematic requirements on final state particles as well as the dynamics of the decay. The effect of mis-identification of the final state particles is simple to configure via configuration files, while the framework can easily be extended to include additional particle types. This paper describes the RapidSim framework, features and some example use cases.

hep-ex↗