Jul 9 – 13, 2018
Sofia, Bulgaria
Europe/Sofia timezone

Online reconstruction of tracks and vertices using the Upgraded Inner Tracking System of ALICE at the LHC

Jul 10, 2018, 4:00 PM
Sofia, Bulgaria

Sofia, Bulgaria

National Culture Palace, Boulevard "Bulgaria", 1463 NDK, Sofia, Bulgaria
Poster Track 1 - Online computing Posters


Matteo Concas (INFN e Politecnico di Torino (IT))


In view of the LHC Run3 starting in 2021, the ALICE experiment is preparing a major upgrade including the construction of an entirely new inner silicon tracker (the Inner Tracking System) and a complete renewal of its Online and Offline systems (O²).

In this context, one of the requirements for a prompt calibration of external detectors and a fast offline data processing is to run online the reconstruction of tracks in the Upgraded Inner Tracking System.

A new algorithm based on Cellular Automata has been developed to tackle this issue. In this algorithm, the tracking is split in multiple phases to profit from data locality and using the same approach it is possible to determine the primary vertex position.

To cope with the specification of the O² and with the foreseen Pb-Pb interaction rate of 50 kHz, this algorithm has been developed exploiting the most common parallelisation technologies available, such as SIMD and multi-threading on x86 CPUs and offloading to GPU using CUDA and OpenCL.

In this contribution we will show the speedup obtained using different technologies to implement the vertexing and tracking algorithms. The obtained computing and physics performance are compliant with the requirements of ALICE for Run 3.

Primary authors

Matteo Concas (INFN e Politecnico di Torino (IT)) Maximiliano Puccio (Universita e INFN Torino (IT)) Iacopo Colonnelli (Universita e INFN Torino (IT)) Stefania Bufalino (Politecnico di Torino (IT)) Massimo Masera (Universita e INFN Torino (IT))

Presentation materials