Davis began his research career at Brookhaven National Laboratory in 1948 after receiving his doctorate in physical chemistry from Yale University. He initially studied neutrinos created in the research reactor at Brookhaven, but the technology available at the time could not detect the neutrinos that physicists believed were generated by nuclear reactions in the Sun.

In the 1970s, Davis tackled this problem by developing an experiment in which solar neutrinos interacted with the chlorine nuclei in a 100 000-gallon tank of dry-cleaning fluid to produce radioactive argon. The tank was placed in a disused gold mine to protect it from the cosmic rays that had prevented scientists detecting solar neutrinos at ground level. Davis went on to confirm that the Sun produced neutrinos, but the discrepancy between the number of neutrinos expected and that observed – which became known as the solar neutrino problem – was only resolved last year.

Davis’ research took him to the University of Pennsylvania in 1984. Among other prizes, he received the 2000 Wolf Prize for his contributions to neutrino physics.

Marvin Cohen

Marvin Cohen’s career began in 1963 after he completed his PhD at the University of Chicago. After spending a year at Bell Labs, he was made a senior scientist at Lawrence Berkeley National Laboratory, a position he still holds. In 1969, he also became professor of physics at the University of California at Berkeley, and has held the post of university professor since 1995.

In the course of his career, Cohen has published nearly 600 research papers on electronic and structural effecst in semiconductors and superconductors, and has received numerous awards.