Nikola Tesla: The Genius

Nikola Tesla was born on July 10, 1856 in Smiljan, Lika, which was then part of the Austo-Hungarian Empire, region of Croatia. His father, Milutin Tesla was a Serbian Orthodox Priest and his mother Djuka Mandic was an inventor in her own right of household appliances. 

Rebuilt, Tesla’s house (parish hall) in Smiljan, now in Croatia, where he was born, and the rebuilt church, where his father served. During the Yugoslav Wars, several of the buildings were severely damaged by fire. They were restored and reopened in 2006.

Tesla studied at the Realschule, Karlstadt in 1873, the Polytechnic Institute in Graz, Austria and the University of Prague. At first, he intended to specialize in physics and mathematics, but soon he became fascinated with electricity. He began his career as an electrical engineer with a telephone company in Budapest in 1881. It was there, as Tesla was walking with a friend through the city park that the elusive solution to the rotating magnetic field flashed through his mind. With a stick, he drew a diagram in the sand explaining to his friend the principle of the induction motor. 

Tesla aged 23, c. 1879

Drawing from U.S. Patent 381,968, illustrating principle of Tesla’s alternating current induction motor

Before going to America, Tesla joined Continental EdisonCompany in Paris where he designed dynamos. While in Strassbourg in 1883, he privately built a prototype of the induction motor and ran it successfully. Unable to interest anyone in Europe in promoting this radical device, Tesla accepted an offer to work for Thomas Edison in New York. His childhood dream was to come to America to harness the power of Niagara Falls. 

Edison Machine Works on Goerck Street, New York.

Young Nikola Tesla came to the United States in 1884 with an introduction letter from Charles Batchelor to Thomas Edison: “I know two great men,” wrote Batchelor, “one is you and the other is this young man.” Tesla spent the next 59 years of his productive life living in New York. Tesla set about improving Edison’s line of dynamos while working in Edison’s lab in New Jersey. It was here that his divergence of opinion with Edison over direct current versus alternating current began. This disagreement climaxed in the war of the currents as Edison fought a losing battle to protect his investment in direct current equipment and facilities.

Tesla pointed out the inefficiency of Edison’s direct current electrical powerhouses that have been build up and down the Atlantic seaboard. The secret, he felt, lay in the use of alternating current, because to him all energies were cyclic. Why not build generators that would send electrical energy along distribution lines first one way, than another, in multiple waves using the polyphase principle?

Edison’s lamps were weak and inefficient when supplied by direct current. This system had a severe disadvantage in that it could not be transported more than two miles due to its inability to step up to high voltage levels necessary for long distance transmission. Consequently, a direct current power station was required at two mile intervals.

Direct current flows continuously in one direction; alternating current changes direction 50 or 60 times per second and can be stepped up to vary high voltage levels, minimizing power loss across great distances. The future belongs to alternating current.

Nikola Tesla developed polyphase alternating current system of generators, motors and transformers and held 40 basic U.S. patents on the system, which George Westinghouse bought, determined to supply America with the Tesla system. Edison did not want to lose his DC empire, and a bitter war ensued. This was the war of the currents between AC and DC. Tesla -Westinghouse ultimately emerged the victor because AC was a superior technology. It was a war won for the progress of both America and the world.

Tesla introduced his motors and electrical systems in a classic paper, “A New System of Alternating Current Motors and Transformers” which he delivered before the American Institute of Electrical Engineers in 1888. One of the most impressed was the industrialist and inventor George Westinghouse. One day he visited Tesla’s laboratory and was amazed at what he saw. Tesla had constructed a model polyphase system consisting of an alternating current dynamo, step-up and step-down transformers and A.C. motor at the other end. The perfect partnership between Tesla and Westinghouse for the nationwide use of electricity in America had begun.

In February 1882, Tesla discovered the rotating magnetic field, a fundamental principle in physics and the basis of nearly all devices that use alternating current. Tesla brilliantly adapted the principle of rotating magnetic field for the construction of alternating current induction motor and the polyphase system for the generation, transmission, distribution and use of electrical power.

Nikola Tesla’s AC dynamo-electric machine (AC electric generator) in an 1888 U.S. Patent 390,721

Tesla’s A.C. induction motor is widely used throughout the world in industry and household appliances. It started the industrial revolution at the turn of the century. Electricity today is generated transmitted and converted to mechanical power by means of his inventions. Tesla’s greatest achievement is his polyphase alternating current system, which is today lighting the entire globe.

Tesla astonished the world by demonstrating the wonders of alternating current electricity at the World Columbian Exposition in Chicago in 1893. Alternating current became standard power in the 20th Century. This accomplishment changed the world. He designed the first hydroelectric powerplant in Niagara Falls in 1895, which was the final victory of alternating current. The achievement was covered widely in the world press, and Tesla was praised as a hero worldwide. King Nikola of Montenegro conferred upon him the Order of Danilo.

Tesla was a pioneer in many fields. The Tesla coil, which he invented in 1891, is widely used today in radio and television sets and other electronic equipment. That year also marked the date of Tesla’s United States citizenship. His alternating current induction motor is considered one of the ten greatest discoveries of all time. Among his discoveries are the fluorescent light, laser beam, wireless communications, wireless transmission of electrical energy, remote control, robotics, Tesla’s turbines and vertical take off aircraft. Tesla is the father of the radio and the modern electrical transmissions systems. He registered over 700 patents worldwide. His vision included exploration of solar energy and the power of the sea. He foresaw interplanetary communications and satellites.

The Century Magazine published Tesla’s principles of telegraphy without wires, popularizing scientific lectures given before Franklin Institute in February 1893. The Electrical Review in 1896 published X-rays of a man, made by Tesla, with X-ray tubes of his own design. They appeared at the same time as when Roentgen announced his discovery of X-rays. Tesla never attempted to proclaim priority. Roentgen congratulated Tesla on his sophisticated X-ray pictures, and Tesla even wrote Roentgen’s name on one of his films. He experimented with shadowgraphs similar to those that later were to be used by Wilhelm Rontgen when he discovered X-rays in 1895. Tesla’s countless experiments included work on a carbon button lamp, on the power of electrical resonance, and on various types of lightning. Tesla invented the special vacuum tube which emitted light to be used in photography.

X-ray Tesla took of his hand

The breadth of his inventions is demonstrated by his patents for a bladeless steam turbine based on a spiral flow principle. Tesla also patented a pump design to operate at extremely high temperature.

Tesla’s bladeless turbine design

Nikola Tesla patented the basic system of radio in 1896. His published schematic diagrams describing all the basic elements of the radio transmitter which was later used by Marconi.

In 1896 Tesla constructed an instrument to receive radio waves. He experimented with this device and transmitted radio waves from his laboratory on South 5th Avenue to the Gerlach Hotel at 27th Street in Manhattan. The device had a magnet which gave off intense magnetic fields up to 20,000 lines per centimeter. The radio device clearly establishes his priority in the discovery of radio.

The shipboard quench-spark transmitter produced by the Lowenstein Radio Company and licensed under Nikola Tesla Company patents, was installed on the U.S. Naval vessels prior to World War I.

In December 1901, Marconi established wireless communication between Britain and the Newfoundland, Canada, earning him the Nobel prize in 1909. But much of Marconi’s work was not original. In 1864, James Maxwell theorized electromagnetic waves. In 1887, Heinrich Hertz proved Maxwell’s theories. Later, Sir Oliver Logde extended the Hertz prototype system. The Brandley coherer increased the distance messages could be transmitted. The coherer was perfected by Marconi.

However, the heart of radio transmission is based upon four tuned circuits for transmitting and receiving. It is Tesla’s original concept demonstrated in his famous lecture at the Franklin Institute in Philadelphia in 1893. The four circuits, used in two pairs, are still a fundamental part of all radio and television equipment.

The United States Supreme Court, in 1943 held Marconi’s most important patent invalid, recognizing Tesla’s more significant contribution as the inventor of radio technology.

Tesla built an experimental station in Colorado Springs, Colorado in 1899, to experiment with high voltage, high frequency electricity and other phenomena.

Tesla’s Colorado Springs laboratory

When the Colorado Springs Tesla Coil magnifying transmitter was energized, it created sparks 30 feet long. From the outside antenna, these sparks could be seen from a distance of ten miles. From this laboratory, Tesla generated and sent out wireless waves which mediated energy, without wires for miles.

In Colorado Springs, where he stayed from May 1899 until 1900, Tesla made what he regarded as his most important discovery– terrestrial stationary waves. By this discovery he proved that the Earth could be used as a conductor and would be as responsive as a tuning fork to electrical vibrations of a certain frequency. He also lighted 200 lamps without wires from a distance of 25 miles (40 kilometers) and created man-made lightning. At one time he was certain he had received signals from another planet in his Colorado laboratory, a claim that was met with disbelief in some scientific journals.

Nikola Tesla sitting in his Colorado Springs laboratory next to his huge “magnifying transmitter” Tesla coil which is producing 22 foot bolts of electricity

The old Waldorf Astoria was the residence of Nikola Tesla for many years. He lived there when he was at the height of financial and intellectual power. Tesla organized elaborate dinners, inviting famous people who later witnessed spectacular electrical experiments in his laboratory.

Financially supported by J. Pierpont Morgan, Tesla built the Wardenclyffe laboratory and its famous transmitting tower in Shoreham, Long Island between 1901 and 1905. This huge landmark was 187 feet high, capped by a 68-foot copper dome which housed the magnifying transmitter. It was planned to be the first broadcast system, transmitting both signals and power without wires to any point on the globe. The huge magnifying transmitter, discharging high frequency electricity, would turn the earth into a gigantic dynamo which would project its electricity in unlimited amounts anywhere in the world.

Tesla’s Wardenclyffe plant on Long Island in 1904. From this facility, Tesla hoped to demonstrate wireless transmission of electrical energy across the Atlantic.

Tesla’s concept of wireless electricity was used to power ocean liners, destroy warships, run industry and transportation and send communications instantaneously all over the globe. To stimulate the public’s imagination, Tesla suggested that this wireless power could even be used for interplanetary communication. If Tesla were confident to reach Mars, how much less difficult to reach Paris. Many newspapers and periodicals interviewed Tesla and described his new system for supplying wireless power to run all of the earth’s industry.

Because of a dispute between Morgan and Tesla as to the final use of the tower. Morgan withdrew his funds. The financier’s classic comment was, “If anyone can draw on the power, where do we put the meter?”

The erected, but incomplete tower was demolished in 1917 for wartime security reasons. The site where the Wardenclyffe tower stood still exists with its 100 feet deep foundation still intact. Tesla’s laboratory designed by Stanford White in 1901 is today still in good condition and is graced with a bicentennial plaque.

Tesla lectured to the scientific community on his inventions in New York, Philadelphia and St. Louis and before scientific organizations in both England and France in 1892. Tesla’s lectures and writings of the 1890s aroused wide admiration among contemporaries popularized his inventions and inspired untold numbers of younger men to enter the new field of radio and electrical science.

Nikola Tesla was one of the most celebrated personalities in the American press, in this century. According to Life Magazine’s special issue of September, 1997, Tesla is among the 100 most famous people of the last 1,000 years. He is one of the great men who divert the stream of human history. Tesla’s celebrity was in its height at the turn of the century. His discoveries, inventions and vision had widespread acceptance by the public, the scientific community and American press. Tesla’s discoveries had extensive coverage in the scientific journals, the daily and weekly press as well as in the foremost literary and intellectual publications of the day. He was the Super Star.

Tesla wrote many autobiographical articles for the prominent journal Electrical Experimenter, collected in the book, My Inventions. Tesla was gifted with intense powers of visualization and exceptional memory from early youth on. He was able to fully construct, develop and perfect his inventions completely in his mind before committing them to paper.

According to Hugo Gernsback, Tesla was possessed of a striking physical appearance over six feet tall with deep set eyes and a stately manner. His impressions of Tesla, were of a man endowed with remarkable physical and mental freshness, ready to surprise the world with more and more inventions as he grew older. A lifelong bachelor he led a somewhat isolated existence, devoting his full energies to science.

In 1894, he was given honorary doctoral degrees by Columbia and Yale University and the Elliot Cresson medal by the Franklin Institute. In 1934, the city of Philadelphia awarded him the John Scott medal for his polyphase power system. He was an honorary member of the National Electric Light Association and a fellow of the American Association for the Advancement of Science. On one occasion, he turned down an invitation from Kaiser Wilhelm II to come to Germany to demonstrate his experiments and to receive a high decoration.

In 1915, a New York Times article announced that Tesla and Edison were to share the Nobel Prize for physics. Oddly, neither man received the prize, the reason being unclear. It was rumored that Tesla refused the prize because he would not share with Edison, and because Marconi had already received his.

On his 75th birthday in 1931, the inventor appeared on the cover of Time Magazine. On this occasion, Tesla received congratulatory letters from more than 70 pioneers in science and engineering including Albert Einstein. These letters were mounted and presented to Tesla in the form of a testimonial volume.

Tesla on Time magazine commemorating his 75th birthday

Tesla died on January 7th, 1943 in the Hotel New Yorker, where he had lived for the last ten years of his life. Room 3327 on the 33rd floor is the two-room suites he occupied.

A state funeral was held at St. John the Divine Cathedral in New York City. Telegrams of condolence were received from many notables, including the first lady Eleanor Roosevelt and Vice President Wallace. Over 2000 people attended, including several Nobel Laureates. He was cremated in Ardsley on the Hudson, New York. His ashes were interned in a golden sphere, Tesla’s favorite shape, on permanent display at the Tesla Museum in Belgrade along with his death mask.

In his speech presenting Tesla with the Edison medal, Vice President Behrend of the Institute of Electrical Engineers eloquently expressed the following: “Were we to seize and eliminate from our industrial world the result of Mr. Tesla’s work, the wheels of industry would cease to turn, our electric cars and trains would stop, our towns would be dark and our mills would be idle and dead. His name marks an epoch in the advance of electrical science.” Mr. Behrend ended his speech with a paraphrase of Pope’s lines on Newton: “Nature and nature’s laws lay hid by night. God said ‘Let Tesla be’ and all was light.”

Nikola Tesla’s Awards and Recognition
In 1917, Tesla was awarded the Edison Medal, the most coveted electrical prize in the United States.
Nikola Tesla’s name has been honored with an International Unit of Magnetic Flux Density called “Tesla.”
The United States Postal Service honored Tesla with a commemorative stamp in 1983.
Tesla was inducted into the Inventor’s Hall of Fame in 1975.
The Nikola Tesla Award is one of the most distinguished honors presented by the Institute of Electrical Engineers. The award has been given annually since 1976.
The Nikola Tesla Statue is located on Goat Island to honor the man whose inventions were incorporated into the Niagara Falls Power Station in 1895. Tesla is known as the inventor of polyphase alternating current.
The Nikola Tesla Corner Sign, located at the intersection of 40th Street and 6th Avenue in Manhattan, is a constant reminder to all New Yorkers of the greatness of this genius.

Nikola Tesla Monument in Zagreb, Croatia

Nikola Tesla Corner in New York City

Nikola Tesla statue in Niagara Falls, Ontario

Nicola Tesla Museum in Belgrade, Serbia

Tesla sitting in front of a spiral coil used in his wireless power experiments at his East Houston St. laboratory

Source: https://www.teslasociety.com/biography.htm
https://en.wikipedia.org/wiki/Nikola_Tesla

Geostaionary Satellite-30

INTRODUCTION:-

India’s telecommunication satellite GSAT-30 was successfully launched into a Geosynchronous Transfer Orbit (GTO) on January 17, 2020 from Kourou  launch base, French Guiana by Ariane-5 VA-251.

GSAT-30 is configured on ISRO’s enhanced I-3K Bus structure to provide communication services from Geostationary orbit in C and Ku bands. The satellite derives its heritage from ISRO’s earlier INSAT/GSAT satellite series.

Weighing 3357 kg, GSAT-30 is to serve as replacement to INSAT-4A spacecraft services with enhanced coverage. The satellite provides Indian mainland and islands coverage in Ku-band and extended coverage in C-band covering Gulf countries, a large number of Asian countries and Australia.

The designed in-orbit operational life of GSAT-30 is more than 15 years.

Render of GSAT-30 spacecraft in deployed configuration with solar panels and reflectors extended.

MISSION :-

The satellite's main communication payload is 12 Ku band transponders for covering Indian mainland and islands and 12 C-brand transponders for extended coverage over Asia and Australia. The satellite will act as a replacement for the defunctioning INSAT-4A. The satellite will provide advanced telecommunication services to the Indian subcontinent. It will be used for VSAT networks, television uplinks, digital satellite newsgathering, DTH services and other communication systems. This is the 41^st communication satellite launched by ISRO and the 24^th launch of ISRO satellite by Arianespace

GSAT-30 (left) is positioned on the adapter that will serve as its interface with Ariane 5 prior to installation atop the launch vehicle. At right, KONNECT is lowered for its integration on the SYLDA dispenser. Photograph courtesy of Arianespace.

India set to boost communication services with launch of GSAT-30

SATELLITE:-

The satellite is based on ISRO's I-3K bus. It was assembled by a consortium of mid-sized industries led by Alpha Design Technologies Ltd. at ISRO Satellite Integration and Test Establishment at Bengaluru.

      Indian telecommunication satellite GSAT-30 was successfully launched into a GTO kourou.

LAUNCH:

GSAT-30 satellite was launched aboard Ariane-5 launch vehicle (VA251) from French Guiana on 21:05 UTC, 16 January 2020 or 02:35 IST, 17 January 2020. After three orbit raising burns with cumulative duration of 2 hours 29 minutes, GSAT-30 acquired station at 81°E on 25 January 2020.

ISRO Chairman K. Sivan 

ISRO's U R Rao Satellite Centre Director P Kunhikrishnan, who was present in Kourou, congratulated the ISRO community and Arianespace team on the successful launch.

Calling it an "excellent start" to 2020 for ISRO with the launch, he said, "The mission team at the master control facility have already acquired the satellite and they will immediately complete the post launch operations."

         Scientist group behind GSAT 30

Reference:-

• Journal 
• Website

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JENEVIA D’CUNHA

JOMY JOSEPH

JOYLINE REBELLO

KAVYA SURESH

LALITHA

1st M.Sc {2nd Semester}     

ORGANIC SOLAR CELL

INTRODUCTION

An organic solar cell or plastic solar cell is a type of photovoltaic that uses organic electronics, a branch of electronics that deals with conductive organic polymers or small organic molecules, for light absorption and charge transport to produce electricity from sunlight by the photovoltaic effect. Most organic photovoltaic cells are polymer solar cells.

The molecules used in organic solar cells are solution-processable at high throughput and are cheap, resulting in low production costs to fabricate a large volume. Combined with the flexibility of organic molecules, organic solar cells are potentially cost-effective for photovoltaic applications. Molecular engineering (e.g. changing the length and functional group of polymers) can change the band gap, allowing for electronic tunability. The optical absorption coefficient of organic molecules is high, so a large amount of light can be absorbed with a small amount of materials, usually on the order of hundreds of nanometers. The main disadvantages associated with organic photovoltaic cells are low efficiency, low stability and low strength compared to inorganic photovoltaic cells such as silicon solar cells.

Compared to silicon-based devices, polymer solar cells are lightweight (which is important for small autonomous sensors), potentially disposable and inexpensive to fabricate (sometimes using printed electronics), flexible, customizable on the molecular level and potentially have less adverse environmental impact. Polymer solar cells also have the potential to exhibit transparency, suggesting applications in windows, walls, flexible electronics, etc. The disadvantages of polymer solar cells are also serious: they offer about 1/3 of the efficiency of hard materials, and experience substantial photochemical degradation.

Polymer solar cells inefficiency and stability problems, combined with their promise of low costs and increased efficiency made them a popular field in solar cell research. As of 2015, polymer solar cells were able to achieve over 10% efficiency via a tandem structure. In 2018, a recordbreaking efficiency for organic photovoltaics of 17.3% was reached via tandem structure.

PHYSICS BEHIND

A photovoltaic cell is a specialized semiconductor diode that converts light into direct current (DC) electricity. Depending on the band gap of the light-absorbing material, photovoltaic cells can also convert low-energy, infrared (IR) or high-energy, ultraviolet (UV) photons into DC electricity. A common characteristic of both the small molecules and polymers used as the light-absorbing material in photovoltaics is that they all have large conjugated systems. A conjugated system is formed where carbon atoms covalently bond with alternating single and double bonds. These hydrocarbons' electrons orbitals delocalize and form a delocalized bonding π orbital with a π* antibonding orbital. The delocalized π orbital is the highest occupied molecular orbital (HOMO), and the π* orbital is the lowest unoccupied molecular orbital (LUMO). In organic semiconductor physics, the HOMO takes the role of the valence band while the LUMO serves as the conduction band. The energy separation between the HOMO and LUMO energy levels is considered as the band gap of organic electronic materials and is typically in the range of 1–4 eV.

All light with energy greater than the band gap of the material can be absorbed, though there is a trade-off to reducing the band gap as photons absorbed with energies higher than the band gap will thermally give off its excess energy, resulting in lower voltages and power conversion efficiencies. When these materials absorb a photon, an excited state is created and confined to a molecule or a region of a polymer chain. The excited state can be regarded as an exciton, or an electron-hole pair bound together by electrostatic interactions. In photovoltaic cells, excitons are broken up into free electron-hole pairs by effective fields. The effective fields are set up by creating a heterojunction between two dissimilar materials. In organic photovoltaics, effective fields break up excitons by causing the electron to fall from the conduction band of the absorber to the conduction band of the acceptor molecule. It is necessary that the acceptor material has a conduction band edge that is lower than that of the absorber material.

COMMERCIALIZATION

Polymer solar cells have yet to commercially compete with silicon solar cells and other thin-film cells. The present efficiency of polymer solar cells lies near 10%, well below silicon cells. Polymer solar cells also suffer from environmental degradation, lacking effective protective coatings.

    

Further improvements in performance are needed to promote charge carrier diffusion; transport must be enhanced through control of order and morphology and interface engineering must be applied to the problem of charge transfer across interfaces.

Research is being conducted into using tandem architecture in order to increase efficiency of polymer solar cells. Similar to inorganic tandem architecture, organic tandem architecture is expected to increase efficiency. Compared with a single-junction device using low-bandgap materials, the tandem structure can reduce heat loss during photon-to-electron conversion.

Polymer solar cells are not widely produced commercially. Starting in 2008, Konarka Technologies started production of polymer-fullerene solar cells. The initial modules were 3–5% efficient, and only last for a few years. Konarka has since filed for bankruptcy, as those polymer solar cells were unable to penetrate the PV market.

CHALLENGES AND FUTURE PLANS

Difficulties associated with organic photovoltaic cells include their low external quantum efficiency (up to 70%) compared to inorganic photovoltaic devices, despite having good internal quantum efficiency; this is due to insufficient absorption with active layers on the order of 100 nanometers. Instabilities against oxidation and reduction, recrystallization and temperature variations can also lead to device degradation and decreased performance over time. This occurs to different extents for devices with different compositions, and is an area into which active research is taking place.

Other important factors include the exciton diffusion length, charge separation and charge collection which are affected by the presence of impurities.

REFERENCE

1.    The Mathrubhumi Printers & Publishers.

2.    Mathrubhumi GK & current Affairs.

3.    Phy.org

4.    Wikipedia

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ABHIJITH K TOMY           

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ANUSREE C                      

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INDRAJ YATHEENDRAN 

Ist MSc Physics

INDIA BASED NEUTRINO OBSERVATORY

 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 6^th and 7^th September 2001 at which various subgroups were formed to study the detector options and electronics, physics goals and simulations, and site survey.

On 18^th 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 5^th 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

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NOBEL LAUREATES IN LASER - 2018

INTRODUCTION
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term “LASER” originated as an acronym for “Light Amplification by Stimulated Emission of Radiation”. The first laser was built in 1960 by Theodore. H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow.

A laser differs from other sources of light in that it emits light coherently. Spatial coherence allows a laser to be a focused to a tight spot, enabling application such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances, enabling applications such as laser pointers and lidar.

Lasers are used in optical disk drives, laser printers barcode scanners, DNA sequencing instruments, fiber-optic and free–space optical communication, laser surgery and skin treatment, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and laser lighting displays for entertainment. They have been used for car headlamps on luxury car, by using a blue laser and a phosphor to produce highly directional white light.

THE THREE NOBEL LAUREATES IN LASER

The 2018 Nobel prize in Physics on October 2 ,2018 was awarded to Arthur Ashkin of USA , Gerard Mourou of France  and Donna Strickland of Canada, making her the third woman to receive the prestigious award. The trio of laureates won the prize for groundbreaking inventions in the field of physics.

ARTHUR  ASHKIN

Arthur Ashkin born on 2 September 1922, is an American Scientist and Nobel laureate who worked at Bell laboratories and Lucent Technologies. Ashkin has been considered by many as the father of optical tweezers, for which he was awarded the Nobel Prize in Physics 2018 at the age of 96, becoming the oldest Nobel Laureate. He resides in Rumson, New Jersey.

Ashkin started his work on manipulation of microparticles with laser light in the late 1960s which resulted in the invention of optical tweezers in 1986. He also pioneered the optical trapping process that eventually was used to manipulate atoms, molecules and biological cells. The key phenomenon is the radiation pressure of light; this pressure can be dissected down into optical gradient and scattering forces.

On October 2, 2018, Arthur Ashkin was awarded a Nobel Prize in Physics for his work on optical trapping sharing it with Donna Strickland and Gerard Mourou who received the other half of that year’s prize. Ashkin was honoured for his invention of optical tweezers that grab particles, atoms, viruses and other living cells with their laser beam fingers. With this he was able to use the radiation pressure of light to move physical objects, ‘an old dream of science fiction’, the Royal Swedish Academy of Sciences said.

At 96, he is the oldest Nobel Prize Laureate to be awarded the prize. Ashkin was awarded half of the prize while half was shared between Gerard Mourou and Donna Strickland for their work on Chirped-Pulse Amplification, a technique “now used in laser machining enables doctors to perform millions of corrective laser eye surgeries every year.”

GERARD MOUROU

Gerard Albert Mourou born on 22 June 1944, is a French Scientist and pioneer in the field of Electrical Engineering and Lasers. He was awarded a Nobel Prize in Physics in 2018, along with the Donna Strickland, for the invention of Chirped-Pulse Amplification, a technique later used to create ultrashort pulse, very high intensity laser pulses.

In 1994, Mourou and his team at the University of  Michigan discovered that the balance between the self-focusing refraction and self-attenuating diffraction by ionisation and rarefaction of a laser beam of terawatt intensities in the atmosphere creates “Filaments” which act as waveguides for the beam thus preventing divergence.


Mourou and Strickland found that stretching a laser out reduced its peak power, which could then be greatly amplified using normal instruments. It could then be compressed to create the short lived, highly powerful lasers they were after. The technique, which was described in Strickland’s first scientific publication, came to known as Chirped Pulse Amplification (CPA). They were probably unaware at the time that tools would make it possible to study natural phenomenon in unprecedented ways. CPA could also per definition be used to create a laser pulse that only lasts one attosecond, one billionth of a billionth of second. At those timescales, it became possible not only to study chemical reactions, but what happens inside individual atoms.

The Guardian and Scientific American Provided Simplified Summaries of the work of Strickland and Mourou: it “paved the way for the shortest, most intense laser beams ever created”. “The ultrabrief, ultrasharp beams can be used to make extremely precise cuts so their technique is now used in laser machining and enables doctors to perform millions of corrective” laser eye surgeries. Canadian Prime Minister Justin Trudeu acknowledge the achievements of Mourou and Strickland: “Their innovative work can be found in applications including corrective eye surgery, and is expected to have a significant impact on cancer therapy and other physics research in the future.”

DONNA STRICKLAND

Donna Theo Strickland born on 27 May 1959, is a Canadian Optical Physicist and pioneer in the field of Pulsed Lasers. She is a Professor at the University of Waterloo.

She served as fellow, vice president, and president of The Optical Society, and is currently chair of their Presidential Advisory Committee. In 2018, she was listed as one of BBC’s 100 Women. She became the third woman ever to be awarded the Nobel Prize in Physics, after Marie Curie  in 1903 and Maria Goeppert Mayer  in 1963. Strickland and Mourou published their pioneering work "Compression of amplified chirped optical pulses" in 1985, while Strickland was still a doctoral student under Mour.

When she received the Nobel Prize, many commentators were surprised that she had not reached the rank of full professor. In response, Strickland said that she had "never applied" for a professorship; "it doesn't carry necessarily a pay raise… I never filled out the paperwork… I do what I want to do and that wasn't worth doing.

TOOLS MADE OF LIGHT

The Inventions being honoured this year have revolutionised laser physics. Extremely small objects and incredibly fast process now appear in a new light. Not only Physics, but also Chemistry, Biology and Medicine have gained precision instruments for use in basic research and practical applications.

WHAT THEY DID?
The Nobel was divided between two major innovations in Laser Technology. Lasers are devices that create and amplify a single source of light. Light that comes out of a laser is one colour, or one wavelength, and does not spread out or weaken the way a flashlight beam would.

Immediately after the invention of lasers in 1960’s Ashkin started trying to, manipulate objects with light, he discovered that small translucent particles could be pushed using the force from a laser beam particles first were trapped in the centre of a beam, and then pinned in place using another laser aimed from the opposite direction. These optical tweezers   could then be used to control and direct individual cells, viruses, proteins, and even atoms.

Strickland and Mourou worked together on laser amplification, producing the shortest and most intense bursts of laser energy ever created by humans. In research that would be used for Strickland‘s doctoral thesis, the pair manipulated beams of light to make them more powerful.

WHY IT MATTERS?
These innovations in light give researchers access to manipulate and study interactions that are too tiny and too fast for conventional methods.

Lasers are used daily in laboratories around the world. Ashkin’s optical tweezers enable scientists to cut, move, contain and inspect particles like strands of DNA and individual cell organelles.

Mourou and Strickland’s CPA method has been used to help millions of people with laser eye surgery and the cameras that use their technology can capture chemical interaction or even electrons in motion around an atom.

CONCLUSION
The inventions being honoured this year have revolutionized Laser Physics. Extremely small objects and incredibly rapid processes as now being seen in a new light. Advanced precision instruments are opening up unexpected areas of research and multitude of industrial and medical applications.

The work of Ashkin, Mourou and Strickland really does fulfill Alfred Nobel’s that the prizes recognize work that has been of the “greatest benefit to mankind”. 

Reference

Journals 

Internet

Submitted by

1.       POOJA KALAL

2.       PRIYANKA VIJAYAN

3.       RESHMA P K

4.       RESHMA RAJAN N

5.       SANGEETHA M

6.       SHILPA A

7.       SHREEVALLI M
Submitted date :21-08-2019