Everything about Neutrinos

• Neutrinos was 1st proposed by Swiss scientist Wolfgang Pauli in 1930.

• It is the 2nd most widely occurring particle in the Universe, after Photons (the particle which makes up light).
• Neutrinos are so abundant among us that every second there are > 100 trillion of them passing right through each of us.
• Properties of Neutrinos
  1. They are subatomic part different from Neutrons. Leptons family. No charge.
  2. In 2015, Nobel Prize was given to Takaaki Kajita and Arthur Mcdonald for discovering Neutrino Oscillations demonstrating that Neutrinos have mass (tiny mass).
  3. Not affected by electromagnetic forces which act on electrons.
  4. Neutrinos occur in 3 different types. They are separated in terms of different masses.
  5. They are the least harmful of all as they almost never react with solid bodies.
• 3 sources = Sun, Black Hole, and Nuclear explosion.
• Significance
  1. They hold answers to fundamental questions on the origin of the Universe.
  2. Another application is in the are of neutrino tomograph of the earth (investigation of the structure of the Earth from Core).
  3. It can also be used for communication.
  4. It can be used to detect nuclear leakages and disasters.
  5. It can be used to detect oil reserves.
  6. It can detect nuke explosion, disaster Ex Japan as their speed > seismic waves.

• Why is the laboratory underground?
  • They are difficult to detect in the laboratory because of their extremely weak interaction with matter. Plus, cosmic rays (interact more than neutrinos) and natural radioactivity can make it impossible to detect on the Earth surface.
  • Hence the observatories are located deep inside the Earth surface.

World Projects

• Underground Observatories
  • Neutrino Oscillation was established by Sudbury Neutrino Observatory, Canada and Super Kamiokande experiment in Japan. They studies solar neutrinos, atmospheric neutrinos and man made neutrinos.
  • It is also at Gran Sasso, Italy.
• Underwater Observatory: Amundsen, Antarctica and Antares - Mediterranean Sea, France.
• Icecube = World's largest Neutrino Telescope - made from giant cube of ice at South Pole, Antarctica. It aims at detecting subatomic particles travelling near the speed oof light. It also detects Dark matter. It is buried deep in ice.

Indian Neutrino Observatory (INO) Project

• INO Project is to be establish at Pottipuram, Theni district (Bodi Hills) in TN. (Charkonite rock)
• The initial goal of INO is to study atmospheric neutrinos only. It is jointly funded by DAE and DST.
• It includes construction of underground laboratory at Pottipuram. 1st phase will study Natural Neutrinos and 2nd phase will study factory made neutrinos from USA, Europe, Japan and Antarctica.
• Construction of an Iron Calorimeter (ICAL) detector for studying neutrino masses. It will detect neutrinos through 150 layers of alternating iron slabs and glass detectors called Resistive plate chambers.
• Setting up of National Centre for High Energy Physics at Madurai for operation of Pottipuram lab, HRD and detector R&D.

NASA’s Antarctic Impulsive Transient Antenna (ANITA)

Recently, NASA’s Antarctic Impulsive Transient Antenna (ANITA) has detected the unusual upward movement of neutrinos in Antarctica.

What is ANITA?

• Antarctic Impulsive Transient Antenna (ANITA) is a radio telescope instrument to detect ultra-high energy cosmic-ray neutrinos from a scientific balloon flying over the continent of Antarctica.
• It involves an array of radio antennas attached to a helium balloon which flies over the Antarctic ice sheet at 37,000 meters.
• At such a height, the antennas can listen to the cosmos and detect high-energy particles, known as neutrinos, which constantly bombard the planet.
• It is the first NASA observatory for neutrinos of any kind.
• ANITA detects neutrinos pinging in from space and colliding with matter in the Antarctic ice sheet through the Askaryan effect.
• The Askaryan effect is the phenomenon whereby a particle traveling faster than the phase velocity of light in a dense dielectric (such as salt, ice or the lunar regolith) produces a shower of secondary charged particles.
• When neutrinos smash into an atom, they produce a shower of detectable secondary particles.These detectable secondary particles allow us to probe where they came from in the universe.
• However, neutrinos pose no threat to human beings and pass through most solid objects. Additionally, they rarely do interact with matter. It is named after Gurgen Askaryan, a Soviet-Armenian physicist who postulated it in 1962.

What is the news?

• Instead of the high-energy neutrinos streaming in from space, they seem to have come from the Earth's interior, before hitting the detectors of ANITA. Usually, the high-energy particles move top to bottom (i.e. from space to the earth). However, ANITA has detected an anomaly i.e. particles have been detected travelling bottom to top.
• Earlier, researchers had also located a deep-space source for high-energy neutrinos through the Ice Cube Neutrino Observatory at a U.S. scientific research station at the South Pole in Antarctica (PT). The India-based Neutrino Observatory (INO) is located at the Bodi West Hills region in Theni District of Tamil Nadu.