Who was the head of the Cavendish Laboratory during Watson and Crick's work?

Lawrence Bragg was the head of the Cavendish Laboratory during Watson and Crick’s work on DNA. More precisely, Sir William Lawrence Bragg served as director of the laboratory from 1938 to 1953.

The Cavendish Laboratory was the University of Cambridge’s major physics research center, but its methods were also transforming biology. Francis Crick worked in an MRC research unit housed there, while James Watson joined the Cambridge effort in the early 1950s. Their work combined model building with evidence from X-ray crystallography and chemical studies.

Bragg was a distinguished physicist who had shared the 1915 Nobel Prize in Physics with his father, William Henry Bragg, for work on X-ray crystallography. That family connection can cause confusion: William Bragg was not the Cavendish director during the DNA breakthrough; Lawrence Bragg was.

Watson and Crick’s first DNA paper appeared in Nature on 25 April 1953. Bragg remained director through that landmark year, making Lawrence Bragg the canonical answer to this question.