Timepix3 Luminosity Determination of LHC Proton-Proton Collisions at 13 TeV

Thomas Seidler

IEAP CTU in Prague

Abstract: The Medipix (MPX) and Timepix (TPX) devices installed in the ATLAS cavern have made important contributions to the overall ATLAS luminosity determinations. In this presentation, we demonstrate for the first time that the Timepix3 chip (TPX3) as the next generation of X-ray and radiation imaging technology can be used for precision luminosity measurements. Rather than collecting data frame-by-frame the TPX3 device generates a continuous stream of data. Thus, new analysis techniques were applied for the luminosity determination.

The data of a TPX3 device operating during 2017 in a first test phase in the ATLAS cavern was analyzed regarding about 100 LHC fills. For the luminosity determination of the LHC proton-proton collisions, Luminosity Blocks (LBs) of typically 60 seconds were defined. These LBs were used to determine LHC luminosity curves reflecting the luminosity reduction from single-bunch interactions and from beam-beam interactions. From these measurements, the internal precision of the TPX3 luminosity was determined.

In addition, the linearity of the TPX3 luminosity measurements with respect to other ATLAS luminometers was determined as a function of the average number of interactions per bunch crossing. Furthermore, the long-term stability of the TPX3 luminosity measurements was determined by comparisons to reference measurements of other ATLAS luminometers, and good agreement was found.

Seminar takes place on Tuesday, January 23rd 2018 at 2:00 PM
in the IEAP meeting room, Praha 2 ‐ Albertov, Horská 3a/22.

doc. Dr. André Sopczak
seminar organizer
doc. Ing. Ivan Štekl, CSc.
headmaster
doc. Dr. André Sopczak
IEEE CS - NPSS chair

IEEE logoNUCLEAR & PLASMA SCIENCES SOCIETY CHAPTER
IEEE Czechoslovakia section
http://www.ieee.cz/en/nps

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