More Like this

1. New approaches for gamma-hadron separation at the IceCube Neutrino Observatory

   https://doi.org/10.1051/epjconf/202328004004  

   Bontempo, Federico ( January 2023 , EPJ Web of Conferences)

   Capone, A. ; De Vincenzi, M. ; Morselli, A. (Ed.)

   The IceCube Neutrino Observatory located at the geographic South Pole is composed of two detectors. One is the in-ice optical array, which measures high-energy muons from air showers and charged particles produced by the interaction of high-energy neutrinos in the ice. The other is an array of ice-Cherenkov tanks at the surface, called IceTop, which is used both as veto for the in-ice neutrino measurements and for detecting cosmic-ray air showers. In the next decade, the IceCube-Gen2 extension will increase the surface coverage including surface radio antennas and scintillator panels on the footprint of an extended optical array in the ice. The combination of the current surface and in-ice detectors can be exploited for the study of cosmic rays and the search for PeV gamma rays. The in-ice detector measures the high-energy muonic component of air showers, whereas the signal in IceTop is dominated by the electromagnetic component. The relative size of the muonic and electromagnetic components is different for gamma-and hadron-induced air showers. Thus, the gamma-hadron separation of cosmic rays is attempted using machine learning techniques including deep learning. Here, different approaches are presented. Finally, the prospects for the detection of PeV photons with IceCube-Gen2 will be discussed. 

   more » « less
2. The IceCube-Gen2 Neutrino Observatory

   https://doi.org/10.1088/1748-0221/16/10/C10007  

   Clark, B.A. ( October 2021 , Journal of Instrumentation)

   Abstract The IceCube Neutrino Observatory opened the window on neutrino astronomy by discovering high-energy astrophysical neutrinos in 2013 and identifying the first compelling astrophysical neutrino source, the blazar TXS0506 + 056, in 2017. In this proceeding, we will discuss the science reach and ongoing development of the IceCube-Gen2 facility, which is the planned extension to IceCube. IceCube-Gen2 will increase the rate of observed cosmic neutrinos by an order of magnitude, be able to detect five-times fainter neutrino sources, and extend the measurement of astrophysical neutrinos several orders of magnitude higher in energy. We will discuss the envisioned design of the instrument, which will include an enlarged in-ice optical array, a surface array for the study of cosmic-rays, and a shallow radio array to detect ultra-high energy (>100 PeV) neutrinos. We will also highlight ongoing efforts to develop and test new instrumentation for IceCube-Gen2. 

   more » « less
3. Sensitivity studies for the IceCube-Gen2 radio array

   https://doi.org/10.22323/1.395.1183  

   Abbasi, Rasha ; Ackermann, Markus ; Adams, Jenni ; Aguilar, Juanan ; Ahlers, M. ; Ahrens, Maryon ; Alispach, Cyril Martin ; Allison, Patrick ; Alves Junior, Antonio Augusto ; Amin, Najia Moureen ; et al ( March 2022 , 37th International Cosmic Ray Conference (ICRC2021))

   The IceCube Neutrino Observatory at the South Pole has measured the diffuse astrophysical neutrino flux up to ~PeV energies and is starting to identify first point source candidates. The next generation facility, IceCube-Gen2, aims at extending the accessible energy range to EeV in order to measure the continuation of the astrophysical spectrum, to identify neutrino sources, and to search for a cosmogenic neutrino flux. As part of IceCube-Gen2, a radio array is foreseen that is sensitive to detect Askaryan emission of neutrinos beyond ~30 PeV. Surface and deep antenna stations have different benefits in terms of effective area, resolution, and the capability to reject backgrounds from cosmic-ray air showers and may be combined to reach the best sensitivity. The optimal detector configuration is still to be identified. This contribution presents the full-array simulation efforts for a combination of deep and surface antennas, and compares different design options with respect to their sensitivity to fulfill the science goals of IceCube-Gen2. 

   more » « less
4. Graph Neural Networks for low-energy event classification & reconstruction in IceCube

   https://doi.org/10.1088/1748-0221/17/11/P11003  

   Abbasi, R. ; Ackermann, M. ; Adams, J. ; Aggarwal, N. ; Aguilar, J.A. ; Ahlers, M. ; Ahrens, M. ; Alameddine, J.M. ; Alves, A.A. ; Amin, N.M. ; et al ( November 2022 , Journal of Instrumentation)

   Abstract IceCube, a cubic-kilometer array of optical sensors built to detect atmospheric and astrophysical neutrinos between 1 GeV and 1 PeV, is deployed 1.45 km to 2.45 km below the surface of the ice sheet at the South Pole. The classification and reconstruction of events from the in-ice detectors play a central role in the analysis of data from IceCube. Reconstructing and classifying events is a challenge due to the irregular detector geometry, inhomogeneous scattering and absorption of light in the ice and, below 100 GeV, the relatively low number of signal photons produced per event. To address this challenge, it is possible to represent IceCube events as point cloud graphs and use a Graph Neural Network (GNN) as the classification and reconstruction method. The GNN is capable of distinguishing neutrino events from cosmic-ray backgrounds, classifying different neutrino event types, and reconstructing the deposited energy, direction and interaction vertex. Based on simulation, we provide a comparison in the 1 GeV–100 GeV energy range to the current state-of-the-art maximum likelihood techniques used in current IceCube analyses, including the effects of known systematic uncertainties. For neutrino event classification, the GNN increases the signal efficiency by 18% at a fixed background rate, compared to current IceCube methods. Alternatively, the GNN offers a reduction of the background (i.e. false positive) rate by over a factor 8 (to below half a percent) at a fixed signal efficiency. For the reconstruction of energy, direction, and interaction vertex, the resolution improves by an average of 13%–20% compared to current maximum likelihood techniques in the energy range of 1 GeV–30 GeV. The GNN, when run on a GPU, is capable of processing IceCube events at a rate nearly double of the median IceCube trigger rate of 2.7 kHz, which opens the possibility of using low energy neutrinos in online searches for transient events. 

   more » « less
5. Measurements of Cosmic Ray Mass Composition with the IceCube Neutrino Observatory

   https://doi.org/10.1051/epjconf/202328302007  

   Plum, Matthias ( January 2023 , EPJ Web of Conferences)

   De Mitri, I. ; Barbato, F.C.T. ; Boncioli, D. ; Evoli, C. ; Pagliaroli, G. ; Salamida, F. (Ed.)

   The IceCube Neutrino Observatory is a multi-component detector at the South Pole. Besides studying high-energy neutrinos, it is capable of measuring high-energy cosmic rays from PeV to EeV. This energy region is thought to cover the transition from galactic to extragalactic sources of cosmic rays. The observatory consists of the deep in-ice IceCube array, which measures the high-energy (≥500 GeV) muonic component, and the IceTop surface array, which is sensitive to the electromagnetic and low-energy muonic part of an air shower. The primary energy and the mass composition can be measured simultaneously by applying statistical methods including modern machine-learning techniques to reconstruct cosmic ray air showers. In this contribution, we will discuss recent improvements to the reconstruction techniques, the mass composition sensitivity, and an outlook on future improved measurements with the full surface scintillator/radio array to mitigate snow accumulation and measure the air shower maximum X max using imaging air-Cherenkov telescopes IceAct. 

   more » « less