The IceCube Neutrino Observatory at the South Pole is a multi-component particle detector consisting of the IceTop surface array and the deep in-ice IceCube array. The foreseen enhancement of the surface instrumentation will consist of plastic scintillator panels read out by silicon photomultipliers. This additional detector component will calibrate the effect of snow accumulation on the IceTop tanks, improve the measurement of cosmic rays, and enhance the atmospheric background rejection for the high-energy astrophysical neutrino detection.
Two scintillator prototype stations were deployed at IceTop in the austral summer of 2017/18 to test the detector design and have started taking data. In order to understand the properties of the scintillator panel response a detailed Geant4 simulation of a single detector, including the photon propagation and simulated SiPM response, is being developed and parameterized. We investigate the capabilities of the IceTop upgrade with an optimized layout of the new detectors and the accuracy of the reconstruction. We will present the details of the simulation and reconstruction studies for the proposed IceTop enhancement and report the capabilities of the combined installation.