The design study of IceCube DeepCore : characterization and veto studies

In this thesis the design study for the low energy extension to the IceCube neutrino telescope, called DeepCore, is presented. IceCube and DeepCore are currently under construction at the geographic South Pole, Antarctica. With DeepCore the energy threshold of IceCube is signi ficantly lowered, opening new possibilities to, e.g., improve low-energy point source searches, to measure standard vacuum neutrino oscillations and to increase the sensitivity to solar dark matter annihilation signals. In parallel to the DeepCore design study a, software based, active atmospheric muon veto technique has been developed, which for the first time, allows IceCube to measure neutrinos with a full sky (4 Pi) acceptance, although at a signi ficantly reduced e ffective volume. Furthermore, in the course of the active atmospheric muon veto development, a new opportunity has been discovered to also reduce the measured rate of atmospheric muon neutrinos, a previously irreducible background to any search for extra-terrestrial neutrinos. This e ffect has been analytically studied, independent of any detector design. As of today, the first data-taking period with full atmospheric muon veto capabilities lies ahead. This thesis concludes with a fi rst look on early data taken with DeepCore and a first estimation of a sensitivity to a southern hemisphere point source