page_title: B. V. Sreekantan
section_title: Career and legacy
hierarchical_section_title: B. V. Sreekantan / Career and legacy
caption_attribution_description: English: A simulation of a cosmic ray shower formed when a proton with 1TeV (1e12 eV) of energy hits the atmosphere about 20km above the ground. The ground shown here is a 8km x 8km map of Chicago's lakefront. This visualization was made by Dinoj Surendran, Mark SubbaRao, and Randy Landsberg of the COSMUS group at the University of Chicago, with the help of physicists at the Kavli Institute for Cosmological Physics and the Pierre Auger Observatory. The simulation was done using the AIRES package by physicist Sergio Sciutto of the Universidad Nacional de La Plata, Argentina. Interactive animated 3d models of this and other cosmic ray showers, as well as instructions on how to make additional ones, can be found at http://astro.uchicago.edu/cosmus/projects/aires.
context_page_description: Badanaval Venkatasubba Sreekantan is an Indian high-energy astrophysicist and a former associate of Homi J. Bhabha at the Tata Institute of Fundamental Research. He is also a Dr. S. Radhakrishnan Visiting Professor at the National Institute of Advanced Studies, Bangalore.
  Known for his studies in the fields of cosmic rays, elementary particles, and high-energy X-ray astronomics, Sreekantan is an elected fellow of all the three major Indian science academies namely, the Indian Academy of Sciences, the Indian National Science Academy and the National Academy of Sciences, India as well as the Maharashtra Academy of Sciences. He was also an associate of Bruno Rossi at Massachusetts Institute of Technology. The Government of India awarded him the Padma Bhushan, India's third highest civilian honour, in 1988.
context_section_description: Sreekantan stayed at TIFR for 39 years, and before his retirement from TIFR service in 1987, he served as the director of the institute from 1975. At TIFR, he initiated many research streams in cosmic ray physics and astrophysics and the research team he established for studies in high energy cosmic rays is still active. One of his early assignments at TIFR was the study of cosmic-ray-produced muons detected deep underground and Sreekantan conducted experiments at Kolar Gold Mines in Karnataka, for the detection of the elementary particles at 2760 m deep. Though his experiments failed to find cosmic ray produced muons, he continued his search, which resulted in the detection of cosmic ray produced neutrinos, reportedly the first detection of the subatomic particles at such depth. His experiments served as the base of his doctoral thesis on the intensity and angular distribution of muons at different depths, prepared under the guidance of Homi Bhabha. A noted Italian experimental physicist, Bruno Rossi of Massachusetts Institute of Technology, examined the thesis and Mumbai University awarded him PhD in 1954.
  Sreekantan's first stint at the Massachusetts Institute of Technology in 1954 was when he worked with Rossi on cloud chambers and K-mesons. During that trip, he visited several laboratories in the UK and France to familiarize himself with the advances in high energy physics. He also visited Brookhaven National Laboratory and conducted experiments on K-meson decay which resulted in the publication of three scientific papers, jointly written with Herbert S. Bridge and others. Once back at TIFR, he started a new series of balloon-borne experiments for studying cosmic X-ray sources above 20 keV which helped in the future development of X-ray detectors for X-ray astronomy missions. Three X-ray instruments developed by his group were carried on the Astrosat, the first multiwavelength astronomy observatory, which was launched in October 2015.
  Sreekantan is known to have furthered the studies of Homi Bhabha and Damodar Dharmananda Kosambi on the lifespan and decay spectrum of muons. He set up his laboratory using war-surplus goods from World War II procured by TIFR as well as from other sources and with the assistance of H. L. N. Murthy, an expert in glass work, who helped him in the development of Geiger counters, he measured the lifespan of the positive muons as 2.24±0.15 microseconds. His findings were published in the Indian journal, Proceedings of Indian Academy of Sciences in 1951.
  When a joint team of Durham University, UK, Osaka City University, and TIFR started experiments for studying neutrinos at a depth of 2.3 km, Sreekantan was a part of the team which recorded 18 events of neutrino interactions in rock. He was also a member of the team that worked on the Grand Unification Theory, to detect the decay of protons in subterranean environment, in the 1970s, the other members of the team included M. G. K. Menon. He assisted Homi Bhabha in the installation of two cloud chambers, Rani and Maharani at the cosmic ray laboratory in Ooty in 1954. Later, a larger cloud chamber, the largest one in India till then, and an air shower array were also set up there, with his assistance. He also designed, together with Subramanian and Ramamurthy, a total absorption spectrometer and an air Cherenkov counter, and the experiments revealed to Sreekantan and his associate, S. C. Tonwar, that increase in energy was an influential factor in the increase of nucleon-anti nucleon production cross section. Their findings have been published in Palau International Coral Reef Center (PICRC) journal in 1979. Along with R. H. Vatcha, he measured charged to neutral (C/N) ratio for high energy hadrons in showers of 1014–1016 eV energy range and arrived at the conclusion that copious production of baryons in high energy interactions is inevitable. These experiments confirmed baryon production in hadron-air nucleus collisions at 1015 eV.
  As the director of the TIFR, he was instrumental in the establishment of several research centres such as Homi Bh
caption: Cosmic ray air shower created by a 1TeV proton hitting the atmosphere 20 km above the Earth (simulation)
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