John Gilbert Daunt (born 30.06.1913) is an experimental physicist. He was born in Ireland. He graduated from the University of Oxford (1937), where he worked in 1937-46. In 1946-65 he was at Ohio University (professor from 1950). From 1965 he has been professor at the Stevens Institute of Technology (New York State) and director of its cryogenic centre.
His research concerned low-temperature physics (the superfluidity of helium, superconductivity, helium-3, the production of low temperatures), solid-state physics, radar, infrared technology and the theory of noise. Together with K. Mendelssohn he discovered (1939) the mechanocaloric effect, measured the thickness of the surface film of liquid helium (50 to 100 atomic layers), studied its thermal conductivity and established (1938) that in the presence of a temperature gradient liquid helium is transferred from a colder place to a warmer one (the discovery of film transfer). He found that the isotope 3He is filtered out when helium II is passed through a narrow slit. He found (1948) an expression for the temperature dependence of the penetration depth.
The F. London Prize (1958).