First partially stripped ions in the LHC ($^{208}$Pb$^{81+}$)

The Gamma Factory initiative proposes to use partially stripped ion (PSI) beams as drivers of a new type of high intensity photon source. As part of the ongoing Physics Beyond Collider studies, initial beam tests with PSI beams have been executed at CERN. On 25 July 2018 lead ions with one remaining electron ($^{208}$Pb$^{81+}$) were injected and accelerated in the LHC for the first time. After establishing the injection and circulation of a few $^{208}$Pb$^{81+}$ bunches, beam lifetimes of about 50 hours could be established at 6.5 TeV proton equivalent energy. This paper describes the setup of the beam tests and observations made.