P.S. Gill (1911-2002): Physicist and instrument designer
PIARA SINGH Gill was born in Hoshiarpur District, Punjab. He had to walk 10 km daily to attend primary school. He matriculated in 1928 from Khalsa High School, Mahilpur and as per the custom in his village, sailed for America in 1929.
Gill worked as a taxi driver in Panama for a year to collect sufficient funds for college education..
On completing junior college in 1932, he earned a merit scholarship at the University of Southern California.
For his maintenance, he did odd jobs like picking fruits, scrubbing floors and washing dishes. He got his M.S. degree in 1936 and then joined the University of Chicago in October 1936 for his doctorate.
He worked under the supervision of the eminent Professor of Physics Arthur Compton (1892-1962). The group under Compton had discovered the latitude effect of cosmic rays.
To state it briefly, cosmic ray intensity shows its minimum value at the equator and then increases up to 40 degree latitude on both sides of the equator with a knee at 45 degree latitude.
For establishing the effect, Gill undertook arduous sea voyages from July 1937 to September 1938 and collected enormous data. He had to make 15 trips between Vanconver (Canada) and Tasmania (Australia). He was awarded Ph.D. in Physics in March 1940.
Gill was keen to work in India. Compton gifted the cosmic ray equipment built by Gill at Chicago, as Gill planned to carry out experiments on the azimuthal variations of cosmic rays. Gill returned home in April 1940.
Gill's career was spent in the following major institutions: Former Christian College, Lahore (1940-47), Tata Institute of Fundamental Research Bombay (1947-48), Atomic Energy Commission Secretariat, New Delhi. (1948-49), Aligarh Muslim University (1949-63), Central Scientific Instruments Organisations (1963-71). He migrated to U.S. in 1972 to live with his daughter at Atlanta, where he died at the ripe age of 101 (March 23, 2002).
Gill presented a paper on the `Size-frequency distribution of cosmic ray bursts' at the International Symposium on Cosmic Rays, June 1939. This is claimed as the first experiment to give clues about the spin of the pi-meson, predicted by the Japanese Physicist Yukava.
At Lahore, he set up his research laboratory to continue in the summer of 1945 the work he had started at Chicago. He used a Royal Air Force `Mosquito' plane to fly up to heights of 33,000 ft. Production of mesons was detected beyond 20,000 ft.
Impressed by the above experimental results, Homi Bhabha offered in July 1947 the post of Professor of Experimental physics at TIFR. With the aid of hydrogen-filled balloons, Gill sent apparatus to high altitudes and recorded the data transmitted on a tape on the ground. He was not sure about his future prospects. So he left TIFR to seek better pastures elsewhere in India and U.S. during the period July 1948 to August 1949.
On September 1, 1949, Gill took charge of the Department of Physics, A.M.U. when the institution was depleted of staff on account of the partition of India. He modernised the laboratories in the fields of Cosmic Rays, Nuclear Physics, Microwave Physics and started courses in Theoretical Physics.
The High altitude laboratory was set up at Gulmarg in 1951. . Studies on the time variations of cosmic rays and extensive air showers at high altitudes were undertaken by his students.
Gill shifted to Chandigarh where he served as Director of CSIO from September 1963 to October 1971. He selected devoted young scientists and launched their careers in the development of new instruments in optics, electronics, environmental medical electronics and process control.
Thus CSIO became wellknown as a leader in sophisticated instrument design.
After retiring he wrote physics text books for high schools which were translated by his student H.S. Virl into Punjabi and published by Rupa & Co, Delhi.(Source: Current Science, Personal News published in Vol. 82, 10 June 2002.)
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