A Characterisation of the ATLAS ITk High Rapidity Modules in AllPix and EUTelescope

The upgrade of the LHC to the high luminosity LHC (HL-LHC) will result in far more collisions occurring per bunch crossing, in turn producing more particles per second. Consequently, the current detectors will need to be upgraded to accommodate the large increase in radiation and data acquisition as well as a need to improve the tracking efficiency for the high pile-up environment. One of the main upgrades to the ATLAS detector is the complete overhaul of the inner detector (ID) by replacing it with an all silicon Inner Tracker (ITk). A simulation of the ITk will be required for performance predictions as well as for testing sample sensors in testbeams. The current testbeam software of Allpix and EUTelescope are written completely using Cartesian definitions, however some of the geometries in the ITk have radial definitions. In particular, the R0 geometry of the strip end-cap is in need of a radial description. Presented is the work behind creating a radial geometry for the R0 module in Allpix (using Geant4 descriptions) and EUTelescope (using TGeo descriptions).