Louis Harold Gray FRS (10 November 1905 – 9 July 1965) was an

English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ide ...

physicist who worked mainly on the effects of radiation on biological systems. He was one of the earliest contributors of the field of

radiobiology Radiobiology (also known as radiation biology, and uncommonly as actinobiology) is a field of clinical and basic medical sciences that involves the study of the action of ionizing radiation on living things, especially health effects of radiation. ...

. 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 Grey (more common in British English) or gray (more common in American English) is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is "without color", because it can be composed o ...

Career

* 1933 - Hospital physicist at

Mount Vernon Hospital Mount Vernon Hospital is located in Northwood, an area of north-west Greater London. It is one of two hospitals run by The Hillingdon Hospitals NHS Foundation Trust. History The hospital was founded as The North London Hospital for Co ...

London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

* 1936 - Developed the

Bragg Bragg may refer to: Places * Bragg City, Missouri, United States * Bragg, Texas, a ghost town, United States * Bragg, West Virginia, an unincorporated community, United States *Electoral district of Bragg, a state electoral district in South Austra ...

–Gray equation, the basis for the cavity ionization method of measuring

gamma-ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically sh ...

energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of hea ...

absorption by materials * 1937 - Built an early

neutron generator Neutron generators are neutron source devices which contain compact linear particle accelerators and that produce neutrons by fusing isotopes of hydrogen together. The fusion reactions take place in these devices by accelerating either deu ...

* 1938 - Studied biological effects of

neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...

s using the generator * 1940 - Developed concept of RBE (

Relative Biological Effectiveness In radiobiology, the relative biological effectiveness (often abbreviated as RBE) is the ratio of biological effectiveness of one type of ionizing radiation relative to another, given the same amount of absorbed energy. The RBE is an empirica ...

) of doses of neutrons * 1952 - Initiated research into cells in hypoxic tumors and

hyperbaric oxygen Hyperbaric medicine is medical treatment in which an ambient pressure greater than sea level atmospheric pressure is a necessary component. The treatment comprises hyperbaric oxygen therapy (HBOT), the medical use of oxygen at an ambient pressure ...

* 1953 - Established the British Empire Cancer Campaign Research Unit in Radiobiology at

which in 1970 became the Cancer Research Campaign’s Gray Laboratory and then (in 2001) the Gray Cancer Institute. * 1953 - 1960 - Under Gray's direction, Jack W. Boag developed pulse radiolysis * 1962 - Ed Hart, of Argonne National Laboratory, and Jack BoagBoag, J. W., & HART, E. J. (1963). Absorption spectra in irradiated water and some solutions: Absorption spectra of ‘hydrated’electron. Nature, 197, 45-47. discovered the

hydrated electron A solvated electron is a free electron in (solvated in) a solution, and is the smallest possible anion. Solvated electrons occur widely. Often, discussions of solvated electrons focus on their solutions in ammonia, which are stable for days, but s ...

using pulse radiolysis at the Gray Laboratory - This discovery initiated a new direction of research that is still very active today and is vital for understanding the effects of radiation on biological tissue, for instance in

cancer treatment Cancer can be treated by surgery, chemotherapy, radiation therapy, hormonal therapy, targeted therapy (including immunotherapy such as monoclonal antibody therapy) and synthetic lethality, most commonly as a series of separate treatments (e.g. ...

References

External links

* Definition o
RBE

founded in 1967
Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology
{{DEFAULTSORT:Gray, Louis Harold 1905 births 1965 deaths Directors of Gray Cancer Institute British physicists Radiobiologists People educated at Christ's Hospital Fellows of the Royal Society 20th-century British botanists Radiation protection Fellows of Trinity College, Cambridge