Louis Harold Gray Explained

Birth Date:	1905 11, df=y
Birth Place:	Richmond upon Thames, England
Death Place:	Northwood, London^[1]
Thesis Year:	1930
Doctoral Advisor:	James Chadwick^[2]
Known For:	Bragg–Gray cavity theory Gray (unit)
Father:	Harry Gray
Mother:	Amy Bowen
Spouse:	Frieda Marjorie Picot

Louis Harold Gray FRS (10 November 1905 – 9 July 1965) was an English physicist who worked mainly on the effects of radiation on biological systems. He was one of the earliest contributors of the field of radiobiology.^[3] Amongst many other achievements, he defined a unit of radiation dosage (absorbed dose) which was later named after him as an SI unit, the gray.

Early life

Gray was born as an only child on 10 November 1905 to parents Harry and Amy Gray. His father worked at a post office.^[4]

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^{[5] [6]}
• 1937 - Built an early neutron generator at Mount Vernon Hospital^[7]
• 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 - Oliver Scott established the British Empire Cancer Campaign Research Unit in Radiobiology^[8] at Mount Vernon Hospital with Hal Gray as director 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^[9]
• 1962 - Ed Hart, of Argonne National Laboratory, and Jack Boag^[10] discovered the hydrated electron 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.

External links

• Definition of RBE
• The LH Gray Memorial Trust founded in 1967
• Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology

Notes and References

1. Web site: LH Gray Memorial Trust: About L.H. Gray.
2. Loutit . J. F. . Scott . O. C. A. . 10.1098/rsbm.1966.0009 . Louis Harold Gray 1905-1965 . . 12 . 2 . 195–217 . 1966 . 1966PMB....11..329. . 73328020 .
3. Sekiya. Masaru . Yamasaki. Michio . Louis Harold Gray (November 10, 1905–July 9, 1965): a pioneer in radiobiology. Radiol Phys Technol . 10. 2–7. 2017. 1 . 10.1007/s12194-016-0379-9. 27714568 . 207402619 . free .
4. Web site: Sekiya . Masaru . Yamasaki . Michio . Louis Harold Gray (November 10, 1905–July 9, 1965): a pioneer in radiobiology . Radiological Physics and Technology . 31 August 2023 . 2–7 . en . 10.1007/s12194-016-0379-9 . 1 March 2017.
5. Gray . Louis Harold . 1936 . An ionization method for the absolute measurement of gamma-ray energy. Proc. R. Soc. Lond. A. 156 . 889. 578–596 . 10.1098/rspa.1936.0169. 1936RSPSA.156..578G . free.
6. Wynchank, S. (2017). Travel. In: Louis Harold Gray . Springer Biographies. Springer, Cham. https://doi.org/10.1007/978-3-319-43397-4_9
7. Alma . Howard . 1965 . Louis Harold Gray . International Journal of Radiation Biology and Related Studies in Physics, Chemistry and Medicine . 9. 5. 509–511. 10.1080/09553006514550571. 5319982 . free .
8. Wynchank, S. (2017). Louis Harold Gray . Springer Biographies. Springer, Cham. https://doi.org/10.1007/978-3-319-43397-4_14
9. Web site: Hill . Kit . 2007-03-26 . Obituary: Jack Boag . 2023-01-24 . the Guardian . en.
10. Boag. J. W.. Hart. E. J.. 1963 . Absorption spectra in irradiated water and some solutions: Absorption spectra of 'hydrated'electron.. Nature. 197. 4862 . 45–47. 10.1038/197045a0. 1963Natur.197...45B . 4277837 .