Neutrino’s, the ultimate global travellers are the biggest introverts full of secrets glimpse of the unknown knowledge.
They are an inscrutable ghost which enigmatically interacts with weak nuclear force. Almost 65 million neutrinos pass through you every second. In 1930, while dealing with radioactive decay scientists found something tizzy. They observed neutrons get converted to protons by knocking out electrons but the energy of electron as compared to energy electron before beta decay wasn’t equal. This flaw of missing energy and angular momentum was amended by wolf gang Pauli by predicting a hypothetical particle whose mass is lesser than any known fundamental particles and does not carry any charge. Enrico Fermi in 1934 coined the term neutrino.
26 years later, In 1956 Clyde Cowan and Fredrick Reines carried out an experiment in South Carolina. Two enormous tanks with scintillator and photomultiplier tubes were implanted near a nuclear reactor which emits about 10 trillion neutrinos every second.
Antineutrino + Proton -> Positron + Neutrinos.
Two distinct gamma rays of 0.5Mev get generated in different directions when a position is hit the electron. Cadmium chloride was dissolved to absorb the neutrons which produced one extra gamma ray after 5×10^-6 seconds later. Frederic Reine, Clyde Cowan, F.B Harrison, H.W Kruse and A.D McGuire were remunerated with Nobel prize in 1995.
Another experiment was conducted in 1964 by Raymond Davis. An underground vat of depth 1478 meters and 380 cubic meter tank filled with tetrachloroethylene was built. Neutrino striking on chlorine atom converts it into an isotope of argon atom but the madding solar problem occurred, the captured solar neutrinos were less than calculated. Scientists came up with an idea of neutrinos oscillations i.e changing their identities, from electron neutrino to tau neutrino to muon neutrino and so on.
The substantiation of neutrinos changing flavours was supported by Super- Kamiokande experiment in 1998.
The underground base zinc mine 3300 feet deep filled with 50,000 tons of water and 13000 photomultiplier tubes formulated on Cherenkov radiation i.e presence of highly energised particle travelling faster than the speed of light in an electrical polarizable medium gives a blink of light which is captured by photomultiplier tubes to reconstruct the trajectory of solar neutrinos. Takaaki Kajata and B McDonald was honoured with the noble prize in 2015 for solving solar neutrino problem