2/27/2023 0 Comments Neutrino detector![]() ![]() If our predictions about the UHE neutrino flux are correct, it will require years of extremely good performance by IceCube, with its cubic-kilometer size, to be able to measure a significant number of those neutrinos. Its major sensitivity is reached above the TeV scale, where the extraterrestrial flux is expected to become increasingly more dominant. IceCube can measure neutrinos with energies above a few dozen GeV, which allows for measuring both the atmospheric and the extraterrestrial fluxes of neutrinos. The highest energies are only accessible with detectors one to three orders of magnitude larger than IceCube. The energy range from keV to several GeV is the domain of underground detectors.The region from tens of GeV to about 100 PeV, with its much smaller fluxes, is addressed by Cherenkov light detectors underwater and in ice. Measured and expected fluxes of natural and reactor neutrinos (details can be found here). Neutrinos with energies around one PeV are predicted to interact while crossing the Earth at a rate of about one event per year per km 2, while those with energies around 100,000 PeV, or 10 20eV, would only interact at a rate of one event per century per km 2. They are produced by the interaction of ultra-high-energy cosmic rays (UHECR) with the cosmic microwave background radiation (CMB). When neutrinos are accelerated to energies above 10 16 electronvolts, or 10 PeV, we cross another energy threshold, into the range of so-called ultra-high-energy (UHE) neutrinos or cosmogenic neutrinos. More extreme energies, in the very high energy range from a few TeVs to up to 10 PeVs, are reached by neutrinos that were created in or near the most extreme objects in our Universe, those powered by black holes and neutron stars. Their energy range expands from a few MeVs (megaelectronvolts = 10 6electronvolts) up to tenths of a PeV. High-energy neutrinos are produced in high-energy particle collisions, such as the ones taking place in the collisions of cosmic rays with the Earth’s atmosphere. None of these low-energy neutrino fluxes can be detected by IceCube. They are similar to the cosmic microwave background (CMB), but bring us information about an even older Universe, just two seconds after the Big Bang. The lowest energy neutrinos, however, are the so-called relic neutrinos or cosmic neutrino background (CNB). Low-energy neutrinos are mainly produced in nuclear processes, such as the ones in the Sun or in the center of an exploding supernova. The energy of a given neutrino, whether it is low or extremely high, tells us about how and where it was produced. Where do the neutrinos observed in IceCube come from? However, thanks to the DeepCore subdetector, which has additional light sensors in the deep, central part of the detector, IceCube can also detect neutrinos with energies as low as 50 GeV. At energies of a few PeVs, or petaelectronvolts, which are a thousand TeVs, (PeV = 10 15electronvolts), cosmic objects beyond our solar system are expected to be the main sources of neutrinos. The IceCube telescope was designed to observe neutrinos with energies around a few tenths of a TeV (teraelectronvolt = 10 12 electronvolts). »»» shows where students could discuss/think about a topic/concept. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |