A Radio Air-Shower Test Array (RASTA) for IceCube

Abstract

In this paper we explore the possibility to complement the cosmic ray physics program of the IceCube observatory with an extended surface array of radio antennas. The combination of air-shower sampling on the surface and muon calorimetry underground offers significant scientific potential: the neutrino sensitivity above the horizon can be enhanced by vetoing air-showers on the ground, photon-induced air-showers can be identified by their small muon component and the coincident measurement of the particle density on the surface and the muon component gives useful information on the composition of the primary flux.All of these analyses are pursued with the existing IceTop array. However, the IceTop footprint is small compared to the acceptance of the InIce sensor array, which severely limits the solid angle for coincident measurements, calling for an extended surface air-shower detector. As demonstrated by the LOPES experiment, measuring air-showers through their geosynchrotron emission has become a viable and cost-efficient method. The science case for the RASTA project -a dedicated radio array seeking to exploit this method at the South Pole -is presented.

Radio detection of cosmic ray air showers in the digital era

“…A number of related activities have been performed, which we will not discuss in detail, but want to mention here shortly. The RASTA [93] project intended to complement the IceCube neutrino detector with a cosmic ray radio detector, in particular for veto purposes. While the project could not be realized, it yielded the result that the rate of transient noise is very low in Antarctica.…”

“…Radio self-triggering might be feasible in environments where the rate of transient RFI is very low. One site that could be suitable is in Antarctica, as indicated by RASTA [93] measurements. The successful selftriggering of cosmic ray events at high frequencies with ANITA [87] over Antarctica lends further support to this.…”

Search for PeVatrons at the Galactic Center using a radio air-shower array at the South Pole

“…A surface array of radio antennas in addition to this could potentially increase the accuracy for the detection of air showers (especially inclined air showers) and for the determination of mass composition. RASTA, a previous study that was made using test antennas at the South Pole explored the possibility of improving veto capabilities and cosmic-ray studies at IceCube [13]. Apart from this, in-ice radio measurements at the South Pole is also being made using ARA, that aims at measuring the radio signals produced by high energy neutrinos inside ice [14].…”