Joseph Rotblat - Nuclear Fall-out

Nuclear Fall-out

Rotblat returned to Britain to become senior lecturer and acting director of research of nuclear physics at the University of Liverpool. He decided not to return to communist Poland and naturalised as a British subject and was joined by his mother, sister, and one of his brothers. He felt betrayed by the use of atomic weapons against Japan, and campaigned for a three year moratorium of all atomic research. Rotblat was determined that his research should have only peaceful ends, and so became interested in the medical and biological uses of radiation. In 1949 he became Professor of Physics at St Bartholomew's Hospital ("Barts"), London, shortly before receiving his PhD from Liverpool in 1950. He also worked on several official bodies connected with nuclear physics, and arranged a major travelling exhibition for schools on civil nuclear energy, the Atom Train.

At St Bartholomew's Rotblat worked on the effects of radiation on living organisms, especially on aging and fertility. This led him to an interest in nuclear fallout, especially strontium-90 and the safe limits of ionising radiation. In 1955, he demonstrated that the contamination caused by the fall-out after the Castle Bravo test at Bikini Atoll nuclear test by the United States would have been far greater than that stated officially. Until then the official line had been that the growth in the strength of atomic bombs was not accompanied by an equivalent growth in radiation released. Japanese scientists who had collected data from a fishing vessel, the Lucky Dragon, which had inadvertently been exposed to fall-out, disagreed with this. Rotblat was able to deduce that the bomb had three stages and showed that the fission phase at the end of the explosion increased the amount of radioactivity by a thousand-fold. Rotblat's paper was taken up by the media and contributed to the public debate that resulted in the ending of atmospheric tests by the Partial Test Ban Treaty.