CERN Accelerating science

Published Articles
Title	Timepix3 Luminosity Determination of 13 TeV Proton-Proton Collisions at the ATLAS Experiment
Author(s)	Sopczak, Andreé (CERN)
Collaboration	ATLAS Collaboration
Publication	2020
Number of pages	2
In:	EPJ Web Conf. 225 (2020) 01002
In:	6th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications, Protoroz, Slovenia, 17 - 21 Jun 2019, pp.01002
DOI	10.1051/epjconf/202022501002
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; ATLAS
Abstract	Medipix and Timepix devices, installed in the ATLAS cavern at the LHC, have provided valuable complementary luminosity information. Results are presented from measurements with Timepix3 (TPX3) detectors. In contrast with previously employed frame-based data acquisition, the TPX3 detector remains active continuously, sending information on pixel hits as they occur. Hit- and cluster-counting methods were used for the luminosity determination of the LHC protonproton collisions. The LHC luminosity versus time is determined using these two methods and fitted to a simple model, which incorporates luminosity reduction from single bunch and beam-beam interactions. The precision of the luminosity determination could be improved by counting the number of clusters, instead of just pixel hits. The internal precision and long-term stability of the TPX3 luminosity measurement are below 0.5%. TPX3, owing to its 1.56 ns time-tagging, is able to resolve the time structure ofthe luminosity due to the collisions of individual proton bunches when integrated over an LHC fill.
Copyright/License	© The Authors (License: CC-BY-4.0)

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