Würzburg 2018 – scientific programme

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T: Fachverband Teilchenphysik

T 44: Experimentelle Methoden der Astroteilchenphysik II

T 44.4: Talk

Tuesday, March 20, 2018, 17:15–17:30, Z6 - SR 2.013

Dark rates from radioactive decays in the multi-PMT digital optical module — •Martin Antonio Unland Elorrieta, Lew Classen, and Alexander Kappes for the IceCube collaboration — Institut für Kernphysik, Westfälische Wilhelms-Universität Münster

In the framework of a planned upgrade of the IceCube Neutrino Observatory and a next-generation neutrino telescope at the South Pole, new optical modules are being developed, which are expected to significantly increase the detector sensitivity. One such concept is the multi-PMT Digital Optical Module (mDOM) which features 24 three-inch PMTs inside a pressure vessel pointing in all directions. This design provides i.a. an almost uniform angular acceptance, an increased effective area and the possibility of using local coincidences between PMTs of the same module. As the deep ice at the South Pole has a very low optical activity, light produced by the mDOM itself represents the dominant background source. Two major sources are Cherenkov and scintillation light produced by radioactive decays inside the module's pressure vessel. After an introduction, the talk presents detailed investigations of the underlying production mechanisms and their parameter, as well as results from a Geant4 simulation of the module response to this background.