Determination of Luminosity With Thermal Neutron Counting Using TPX Detectors in the ATLAS Cavern in LHC Proton-Proton Collisions at 13 TeV

A network of Timepix (TPX) devices installed in the ATLAS cavern has the unique capability of measuring the luminosity with thermal neutron counting in Large Hadron Collider proton-proton collisions at 13 TeV. Compared with the hit-counting method, the method of thermal neutron counting has the advantage that it is not affected by induced radioactivity. The results of the luminosity determination are presented for several independently operated TPX detectors. The long-term time stability measurements of the luminosity are presented for individual devices and between different devices. The high-statistics data sets allow a detailed comparison between neutron counting and hit-counting luminosity determinations.