Measurement of the radiation environment of the ATLAS cavern in 2017–2018 with semiconductor pixel ATLAS-GaAsPix detectors Friday, May 28, 2021 Dear colleagues! Please find details related to the institutional seminar on results obtained by the JINR team at the ATLAS at the LHC on 28 May at 11:00. Due to the measures imposed by the JINR Directorate for preventing the spread of the coronavirus COVID-19 infection the seminar will be held via Zoom only. See please brief instructions on Zoom system use Speaker: E.A. Cherepanova Title: «Measurement of the radiation environment of the ATLAS cavern in 2017–2018 with semiconductor pixel ATLAS-GaAsPix detectors» Abstract: A network of ten semiconductor Timepix detectors with GaAs:Cr sensors was installed in the ATLAS cavern at CERN's LHC during the shutdown periods 2015–2016 and 2016–2017 in the framework of a cooperation between ATLAS and the Medipix2 Collaboration. The purpose was to augment the existing system of measuring and characterising the radiation environment in the ATLAS cavern that is based on ATLAS-TPX devices with pixelated silicon sensors. The detectors were in continuous operation during 13 TeV proton-proton collisions in 2017–2018. Data were recorded during proton-proton bunch crossings, and during times without bunch crossings (LHC physics runs) as well as between the physics runs. The detectors recorded all interactions of charge particles, neutrons and photons in GaAs sensors, in which the signal was higher than 6.5 keV in individual pixels. This made it possible to register clusters (tracks) of individual radiation particles interacting in the detectors sensors. During the LHC beam-beam collisions the radiation background contains particles produced at the interaction point which punch through the ATLAS detector. In the periods without beam-beam collisions, there were photons and electrons resulting from radioactivity induced during previous collisions in GaAs detectors and in surrounding construction materials, namely by neutrons. The ATLAS-GaAsPix Network measured overall level of particle radiation, the ratio between neutral and charged particles as well as neutron flux distribution in the cavern by measuring a level of induced radioactivity in the sensor materials. Link to the publication Agenda PIN: 20210528 Connect to Zoom meeting Meeting ID: 681 7571 4615 Password: 487601