India based Neutrino Observatory (INO) is a
particle physics research project under construction to primarily study
atmospheric neutrinos in a 1,200 meters (3900 ft) deep cave under INO Peak
near Theni in Tamil Nadu, India. This project is notable in that it is
anticipated to provide a precise measurement of neutrino mixing parameters. The
project is a multi-institute collaboration and one of the biggest experimental
particle physics project undertaken in India.
The project was originally to be completed
in 2015 at an estimated cost of Rs 1500 crores (US $ 209.7 million), has been
cleared by the ministry of environment for construction in the Bodi West Hills
Reserved Forest in the Theni District in Tamil Nadu. Although delayed, the
project is underway as of 2015.
When completed, the magnetised iron
calorimeter (ICAL) experiment will include the world’s largest magnet, four
times larger than the 12,500-tonne magnet in the Compact Muon Solenoid detector
at CERN in Geneva, Switzerland.
IRON CALORIMETER (ICAL) DETECTOR:
The main experiment proposed at the INO is
the Iron-Calorimeter Detector which aims to probe the earth matter effects on
the propagation of atmospheric neutrinos and to determine neutrino oscillation
parameters in the 2-3 oscillation sectors. ICAL will be a 50000 tonne
magnetised detector with iron as the passive detector element and the resistive
plate chambers (RPCs) as the active detector elements. That is, the neutrinos
will interact with iron to produce final state particles which have charge and
will record the signals and these signals which have position and timing
information will help us reconstruct the tracks and/or showers and thus the
energy and directions of the final state particles and also the incident
neutrinos.
The ICAL design is mostly based on the
Monolith detector. ICAL detector will have three modules, each module will have
151 layers of iron and 150 layers of RPCs stacked one over the other. The
dimension of the entire detector will be 48m x 16m x 14.5m. The detector, owing
to its huge size, will require around 30000 glass RPCs for the purpose of charged
particle detection. ICAL being a neutrino detector will be situated underground
to reduce the cosmic ray muon signal.
The location of INO has attracted a lot of
attention from the neutrino physics community as the distance between INO and CERN
is very close to “magic baseline” - a distance at which the effect of the CP
phase on the measurement is minimal. But the major physics advantage of INO
ICAL is its ability to measure neutrino mass hierarchy via studying atmospheric
neutrinos. Currently ICAL is the only proposed magnetised detector which can
resolve mass hierarchy via studying the survival of muon neutrinos and
anti-neutrinos.
NEUTRINO:
A neutrino is a fermion that interacts only
via the weak subatomic force and gravity. The neutrino is so named because its
rest mass is so small. The weak force has a very short range, the gravitational
interaction is extremely weak, and neutrinos, as leptons, do not participate in
the strong interaction. Thus, neutrinos typically pass through normal matter
unimpeded and undetected.
Weak interactions create neutrinos in one of the three leptonic flavors; electron neutrinos, muon neutrinos and tau neutrinos, in association
with the corresponding charged lepton. Although neutrinos were long believed to
be massless, it is now known that there are three discrete neutrino masses
with different tiny values, but they do not correspond uniquely to the three
flavours. A neutrino created with a specific flavour has an associated specific
quantum superposition of all three mass states.
For each neutrino, there also exists a
corresponding antiparticle, called an anti neutrino, which also has
half-integer spin and no electric charge. They are distinguished from the neutrinos
by having opposite signs of leptons number and chirality. To conserve total
lepton number, in nuclear beta decay, electron neutrinos appear together with
only positrons (anti electrons) or electron – antineutrinos, and electron
antineutrinos with electrons or electron neutrinos.
Neutrinos are created by various
radioactive decays, including the following:
1. In beta decay of atomic nuclei or
hadrons.
2. During a supernova.
3. In the spin-down of neutron star.
4. When accelerated particle beams or
cosmic rays strike atoms.
The majority of neutrinos detected in the
vicinity of the earth are from nuclear reaction in the sun.
In the vicinity of the Earth, about 65
billion solar neutrinos per second pass through every square centimetre
perpendicular to the direction of the sun.
HISTORY
The possibility of a neutrino observatory
located in India was discussed as early as 1989 during several meetings held at
that year. The issue was raised again in the first meeting of the neutrino
physics and the cosmology working group during the workshop on High Energy
Physics Phenomenology (WHEPP-6) held at Chennai in January 2000 and it was
decided then to collates concrete ideas for a neutrino detector.
Further discussions took place in August
2000 during a meeting on Neutrino Physics at the Saha Institute of Nuclear
Physics, Kolkata, when a small group of neutrino physics enthusiasts started
discussing the possibilities. The neutrino 2001 meeting was held in the
Institute of Mathematical Sciences, Chennai, during February 2001 with the
explicit objective of bringing the experimentalists and theorists in this field
together. The INO collaboration was formed during this meeting. The first
formal meeting of this collaboration of this meeting was held in Tata Institute
of Fundamental Research, Mumbai, during 6th and 7th
September 2001 at which various subgroups were formed to study the detector
options and electronics, physics goals and simulations, and site survey.
On 18th October 2010, the Ministry of Environment and Forests approved both environment and forest clearance
for setting up the observatory in the Bodi West Hills Reserved Forest in the Theni
district of Tamil Nadu.
On 5th January 2015, union
cabinet headed by Prime Minister Narendra Modi approved to set up the India
Based Neutrino Observatory (INO).
Reference:
Internet
Mathrubhumi G K & Current Affairs
Submitted by
Indraj Yatheendran
Gokul Das T
Abhijith K Tomy
Anusree C
Amrutha K T
Gopika A K
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