Designs of the Deep-ice Optical Sensor Array for IceCube-Gen2

IceCube-Gen2 is a planned large-scale extension of the IceCube Neutrino Observatory at the geographic South Pole. It will consist of scintillation panels on the surface, buried radio antennas, and the IceCube-Gen2 optical array embedded in the deep and transparent glacial ice. The IceCube-Gen2 optical array is a three-dimensional arrangement of optical modules (OMs) that are the fundamental light sensors sensitive to Cherenkov light. IceCube-Gen2 builds on a successful decade of scientific observations with IceCube and is optimized to search for sources of astrophysical neutrinos from TeV to EeV energies in a cost-efficient way. Although at 120 the number of strings with optical sensors is only about 40% greater than that of IceCube, the doubling of horizontal spacing combined with the extension to greater and shallower depths allows instrumentation of a volume eight times that of IceCube. Furthermore, the IceCube-Gen2 array utilizes a minimized deployment hole. The construction cost approximately scales with the volume of the deployment holes for a deep ice array. Therefore, reducing hole diameter by 10% will reduce the construction cost by about 20%. However, this cost-effective IceCube-Gen2 design makes some strenuous demands on the OM design in maximizing their sensitivity while minimizing their diameters. This contribution describes the design and status of the newly designed Gen2 OMs for the IceCube-Gen2 optical sensor array