Speaker
Description
Over the last decade, LOFAR has been used to measure radio signals from high-energy cosmic rays around 10^17 eV. These produce air showers, a cascade of secondary particles reaching a peak at an atmospheric depth called X_max which is sensitive to the primary particle's mass. The SKA-Low telescope being constructed in Australia presents a two orders of magnitude increase in number of antennas, featuring nearly 60,000 antennas in a 1 km diameter area. A simulation study building on our experience with LOFAR shows that SKA will be able to track the air shower evolution into more detail than just its maximum X_max. This would help in determining the cosmic-ray mass composition more accurately, and in particular the proton fraction which is astrophysically relevant, yet difficult to distinguish from helium. Moreover, the main hadronic interaction models predict observably different shower profiles. Hence, measuring these would be helpful in constraining hadronic physics beyond energy levels accessible in particle colliders. I will give an overview of the technique and of the unique capabilities of SKA-Low for high-energy cosmic-ray measurements.
