The Prototype Station for the IceCube Surface Array Enhancement

IceTop, the surface array of the IceCube Neutrino Observatory at the geographic South Pole, serves as both, a veto for the in-ice neutrino detection and a cosmic-ray detector. It consists of 162 ice-Cherenkov tanks, distributed over an area of 1 km$^2$. Due to snow accumulation on top of the tanks, the resolution of IceTop decreases and the energy threshold increases.

The Surface Array Enhancement (SAE) will measure and mitigate the effects of the snow accumulation, enhance the veto capabilities and improve cosmic-ray measurements by increasing the detection sensitivity in the primary energy range of 100 TeV to 1 EeV. Additionally, it serves as R&D for the large-scale surface array of IceCube-Gen2, the planned next generation neutrino detector at the South Pole. 32 stations will be deployed within the current IceTop footprint. Each station comprises of eight elevated scintillation detectors with SiPM readout and three radio antennas, connected to a central DAQ.

In the frame of this thesis, the designs of two initial R&D stations have been merged and optimized for the SAE. A prototype station was built and deployed at the South Pole in January 2020. ... mehrThe characterization and calibration of the scintillation detectors show a high light yield for individual particles, which enables a low energy threshold. Temperature effects of the SiPM readout are evaluated and compensated in the data analysis.

First analyses of air-shower data of the prototype station are performed. A method to combine the data from the single detectors to air-shower events is established. The comparison of measured events with expectations from simulations shows agreement. Therefore, it can be concluded that the simulations are valid and that the scintillation detector effects are understood. For events, which are measured in coincidence with the scintillation detectors and IceTop, the comparison of the reconstruction results show that the angular resolution of a single station for events with coincident hits from eight scintillation detectors is competitive to the IceTop reconstruction. For triple coincidences, i. e. events measured in coincidence with the scintillation detectors, radio antennas and IceTop the reconstruction results of the zenith angle agree within 4 degree.

Based on these results, not only the design for the SAE is validated for the production of the 32 stations, but also several hints could be provided for improvements, in particular related to the firm- and software of the detector system. In addition, the design will be used as the baseline design for the future surface array of IceCube-Gen2. The experimental verification of the simulation confirms the simulation basis for IceCube-Gen2. These are important steps in the planning, optimization and realization of IceCube-Gen2.