Louis Harold Gray

Louis Harold Gray (10 November 1905 - 9 July 1965) was a British physicist who worked mainly on the effects of radiation on biological systems, inventing the field of radiobiology as he went. A summary of his work is given below. Amongst many other achievements, he defined a unit of radiation dosage which was later named after him as an SI unit, the Gray.

Summary of Career

 * 1933 Hospital physicist at Mount Vernon Hospital, London
 * 1936 Developed the Bragg-Gray equation, the basis for the cavity ionization method of measuring gamma-ray energy absorption by materials
 * 1937 Built an early neutron generator at Mount Vernon
 * 1938 Studied biological effects of neutrons using the generator
 * 1940 Developed concept of RBE (Relative Biological Effectiveness) of doses of neutrons
 * 1952 Initiated research into cells in hypoxic tumors and hyperbaric oxygen
 * 1953 Set up Gray Laboratory at Mount Vernon Hospital
 * 1953 - 1960 Under Gray’s direction, Jack W. Boag developed pulse radiolysis
 * 1962 Ed Hart (ANL) and Boag discovered the hydrated electron using pulse radiolysis at Gray Lab

This discovery initiated a new direction for chemistry research that is still very active today and is vital for understanding of the effects of radiation on biological tissue, for instance in cancer treatment.