Speaker
Description
We present the results of a new cosmic ray composition analysis above $10^{16.8}$ eV, based on measurements of the depth of air shower maximum $X_{\rm max}$ using the LOFAR radio telescope.
The reconstruction is done by simulating the radio signal for an ensemble of showers using Corsika and CoREAS.
The radio footprints on the ground are fitted to the measured radio data, yielding an $X_{\rm max}$ estimate to a precision of about 20 g/$\mathrm{cm^2}$.
Improvements on previous results include accounting for variations in the atmosphere by producing simulations with event-specific profiles for the pressure, humidity, and refractive index. Moreover, the energy estimate and the fitting procedure are now done exclusively on the radio signals, based on an improved antenna calibration using the Galactic background signal.
The combination of these and other improvements lead to a considerable reduction in systematic uncertainties on $X_{\rm max}$ and the shower energy.
