IceAct Commissioning at South Pole

Leif Raedel at the South Pole Copyright: © Jan Auffenberg

The deployment crew together with the IceAct prototype (right), a compact imaging Cherenkov telescope, at the geographic South Pole in December 2015. This is the first time ever that SiPMs are used for an experiment at the South Pole.


Successful commissioning of the first imaging air Cherenkov telescope prototype, IceAct, for IceCube at the South Pole.

IceCube-Gen2 is planned to extend the IceCube Neutrino Observatory at the geographic South Pole. For neutrino astronomy, a large background-free sample of well-reconstructed astrophysical neutrinos is essential. The main background for this signal are muons and neutrinos which are produced in cosmic-ray air showers in the Earth's atmosphere. The coincident detection of these air showers by the surface detector IceTop has been proven to be a powerful veto for atmospheric neutrinos and muons in the field of view of the Southern Hemisphere. This motivates a large extension of IceTop to more efficiently detect cosmic rays, IceVeto. Part of these extension plans is the IceAct array. Compared to IceTop stations, these telescopes potentially lower the detection threshold for air showers at the cost of a lower duty cycle.

This December a first IceAct prototype, entirely developed by the III. Institute for Particle Physics at the RWTH Aachen University was deployed at the South Pole. The IceAct prototype consists of a compact 7 pixel SiPM camera and lens optics with an aperture of 50cm and an f/1 of 1. The whole system was optimized for harsh and cold environments. The goal of this first installation at the South Pole is to determine the conditions for air shower detection with SiPM based imaging air Cherenkov telescopes in this environment. The IceAct prototype was successfully commissioned and is currently taking background data.

In the end of January the integration of the telescope into the IceCube experiment will be finalized. This is the first time ever that SiPMs are used for an experiment at the South Pole. By the end of March it will be dark enough to start recording signals from air-showers with the IceAct prototype in coincidence with the IceCube neutrino observatory.