Irradiation induced effects in the FE-I4 front-end chip of the ATLAS IBL detector

The ATLAS Insertable B-Layer (IBL) detector was installed into the ATLAS experiment in 2014 and has been in operation since 2015. During the first year of IBL data taking an increase of the low voltage currents associated with the FE-I4 front-end chip was observed and this increase was traced back to the radiation damage in the chip. The dependence of the current on the total-ionising dose and temperature has been tested with X-ray and proton irradiations and will be presented in this paper together with the detector operation guidelines.