Antineutrinos with an energy above the threshold of 1.8 MeV caused charged current interactions with the protons in the water, producing positrons and neutrons. Two scintillation detectors were placed next to the cadmium targets. Reines and Cowan used two targets containing a solution of cadmium chloride in water. Because the interaction involves the exchange of a charged boson, the target particle also changes character (e.g., neutron → proton).Īntineutrinos were first detected in 1956 near a nuclear reactor. A detector which can distinguish among these leptons can reveal the flavor of the incident neutrino in a charged current interaction. Most accelerator-based neutrino beams can also create muons, and a few can create taus. Solar and reactor neutrinos have enough energy to create electrons. However, if the neutrino does not have sufficient energy to create its heavier partner's mass, the charged current interaction is unavailable to it. In a charged current interaction, the neutrino transforms into its partner lepton (electron, muon, or tau). However, no neutrino flavor information is left behind.
All three neutrino flavors can participate regardless of the neutrino energy. an electron), it may be accelerated to a relativistic speed and consequently emit Cherenkov radiation, which can be observed directly. If the target particle is charged and sufficiently light (e.g. In a neutral current interaction, the neutrino leaves the detector after having transferred some of its energy and momentum to a target particle. Neutrinos can interact via the neutral current (involving the exchange of a Z boson) or charged current (involving the exchange of a W boson) weak interactions. The proposed acoustic detection of neutrinos via the thermoacoustic effect is the subject of dedicated studies done by the ANTARES and IceCube collaborations. MINOS uses a solid plastic scintillator watched by phototubes, Borexino uses a liquid pseudocumene scintillator also watched by phototubes while the proposed NOνA detector will use liquid scintillator watched by avalanche photodiodes. Other detectors have consisted of large volumes of chlorine or gallium which are periodically checked for excesses of argon or germanium, respectively, which are created by neutrinos interacting with the original substance. The Sudbury Neutrino Observatory is similar, but uses heavy water as the detecting medium. Super Kamiokande is a large volume of water surrounded by phototubes that watch for the Cherenkov radiation emitted when an incoming neutrino creates an electron or muon in the water. Various detection methods have been used. The field of neutrino astronomy is still very much in its infancy – the only confirmed extraterrestrial sources so far are the Sun and supernova SN1987A. Neutrino detectors are often built underground to isolate the detector from cosmic rays and other background radiation. Because neutrinos are only weakly interacting with other particles of matter, neutrino detectors must be very large in order to detect a significant number of neutrinos.
A neutrino detector is a physics apparatus designed to study neutrinos.
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