  Since 2019 a collaboration between researchers from various institutes and
experiments (i.e. ATLAS, CMS, ALICE, LHCb/SHiP and the CERN EP-DT group), has
been operating several RPCs with diverse electronics, gas gap thicknesses and
detector layouts at the CERN Gamma Irradiation Facility (GIF++). The studies
aim at assessing the performance of RPCs when filled with new eco-friendly gas
mixtures in avalanche mode and in view of evaluating possible ageing effects
after long high background irradiation periods, e.g. High-Luminosity LHC phase.
This challenging research is also part of a task of the European AidaInnova
project.
  A promising eco-friendly gas identified for RPC operation is the
tetrafluoruropropene (C$_{3}$H$_{2}$F$_{4}$, commercially known as HFO-1234ze)
that has been studied at the CERN GIF++ in combination with different
percentages of CO$_2$. Between the end of 2021 and 2022 several beam tests have
been carried out to establish the performance of RPCs operated with such
mixtures before starting the irradiation campaign for the ageing study.
  Results of these tests for different RPCs layouts and different gas mixtures,
under increasing background rates are presented here, together with the
preliminary outcome of the detector ageing tests.
