https://doi.org/10.1051/epjconf/201715000013
Online Data Reduction using Track and Vertex Reconstruction on GPUs for the Mu3e Experiment
Institut für Kernphysik, Johann-Joachim-Becher-Weg 45, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
a e-mail: vombruch@uni-mainz.de
Published online: 8 August 2017
The Mu3e experiment searches for the lepton flavour violating decay μ+ → e+e−e+, aiming to achieve a sensitivity of 2 · 10−15 in its first phase and ultimately aspiring to a final sensitivity of 10−16. During the first phase of the experiment, a muon rate of ∼ 108 μ/s will be available, resulting in a data rate of ∼ 80 Gbit/s. The trigger-less readout system is based on optical links and switching FPGAs sending the complete detector data for a time slice to one node of the filter farm. A full online reconstruction is necessary to reduce the data rate to a manageable amount to be written to disk. Graphics processing units (GPUs) are used to fit tracks with a non-iterative 3D tracking algorithm for multiple scattering dominated resolution. In addition, a three track vertex selection is performed by calculating the vertex position from the intersections of the tracks. Together with kinematic cuts, this allows for a reduction of the output data rate to below 100MB/s using 12 DAQ PCs.
© The Authors, published by EDP Sciences, 2017
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
