David Sayre (March 2, 1924 – February 23, 2012) was an American scientist, credited with the early development of direct methods for

protein crystallography X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...

and of diffraction microscopy (also called

coherent diffraction imaging Coherent diffractive imaging (CDI) is a "lensless" technique for 2D or 3D reconstruction of the image of nanoscale structures such as nanotubes, nanocrystals, porous nanocrystalline layers, defects, potentially proteins, and more. In CDI, a highl ...

). While working at IBM he was part of the initial team of ten programmers who created FORTRAN, and later suggested the use of

electron beam lithography Electron-beam lithography (often abbreviated as e-beam lithography, EBL) is the practice of scanning a focused beam of electrons to draw custom shapes on a surface covered with an electron-sensitive film called a resist (exposing). The electron ...

for the fabrication of X-ray Fresnel zone plates. The

International Union of Crystallography The International Union of Crystallography (IUCr) is an organisation devoted to the international promotion and coordination of the science of crystallography. The IUCr is a member of the International Council for Science (ICSU). Objectives T ...

awarded Sayre the

Ewald Prize Ewald is a given name and surname used primarily in Germany and Scandinavia. It derives from the Germanic roots '' ewa'' meaning "law" and '' wald'' meaning "power, brightness". People and concepts with the name include: Surnames * Douglas Ewald ...

in 2008 for the "unique breadth of his contributions to crystallography, which range from seminal contributions to the solving of the phase problem to the complex physics of imaging generic objects by X-ray diffraction and microscopy(...)".

Life and career

Sayre was born in

New York City New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the Un ...

. He completed his bachelor's degree in physics at

Yale University Yale University is a private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and among the most prestigious in the worl ...

at the age of 19. After working at the

MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...

Radiation Laboratory, he earned his MS degree at

Auburn University Auburn University (AU or Auburn) is a public land-grant research university in Auburn, Alabama. With more than 24,600 undergraduate students and a total enrollment of more than 30,000 with 1,330 faculty members, Auburn is the second largest uni ...

in 1948. In 1949, he moved to Oxford with his wife Anne Colquhoun, whom he had married in 1947. Sayre completed his doctoral studies in

Dorothy Hodgkin Dorothy Mary Crowfoot Hodgkin (née Crowfoot; 12 May 1910 – 29 July 1994) was a Nobel Prize-winning British chemist who advanced the technique of X-ray crystallography to determine the structure of biomolecules, which became essential for ...

's group in 1951. It is at this time that Sayre discovered the equation now named after him, based on the concept of atomicity. Although the key to most direct methods still in use today, Sayre did not share the 1985 chemistry Nobel prize awarded for their discovery. It is also around this time that Sayre, inspired by

Claude Shannon Claude Elwood Shannon (April 30, 1916 – February 24, 2001) was an American mathematician, electrical engineer, and cryptographer known as a "father of information theory". As a 21-year-old master's degree student at the Massachusetts Insti ...

's recent work, suggested in a short paper that the crystallographic phase problem could be solved more easily if one could measure intensities at a higher density than imposed by Bragg's law. This insight is widely seen as the initial spark that lead to recent lensless imaging techniques. Back in United States, David Sayre worked on structure determination of a carcinogen molecule in the lab of Peter Friedlander at the

University of Pennsylvania The University of Pennsylvania (also known as Penn or UPenn) is a Private university, private research university in Philadelphia. It is the fourth-oldest institution of higher education in the United States and is ranked among the highest- ...

Philadelphia Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Since ...

. The structure determination program he wrote for the IBM 701 attracted the attention of

John Backus John Warner Backus (December 3, 1924 – March 17, 2007) was an American computer scientist. He directed the team that invented and implemented FORTRAN, the first widely used high-level programming language, and was the inventor of the Backu ...

, who hired him to be part of the initial team of 10 programmers that developed the high-level programming language FORTRAN at IBM for the IBM 704 mainframe. Sayre remained at IBM until his retirement in 1990. In the early 1970s, Sayre became interested in X-ray microscopy. He suggested to use the newly developed

apparatus at IBM to produce Fresnel zone plates, a type of X-ray lens now widely used in Synchrotron facilities. In the '80s, he came back to the goal of achieving lensless imaging, which he pursued the rest of his life.

References

External links

Obituary: David Sayre (1924–2012) Crystallographer who pioneered methods of X-ray imaging and modern computing
by Janos Kirz and Jianwei Miao,

Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are p ...

journal, Volume 484 Number 7392, p. 34, April 2012.
Obituary: David Sayre (1924–2012)
by Jenny P. Glusker,

Acta Crystallographica ''Acta Crystallographica'' is a series of peer-reviewed scientific journals, with articles centred on crystallography, published by the International Union of Crystallography (IUCr). Originally established in 1948 as a single journal called ''Acta ...

, Volume 68, p. 1–2, May 2012.
Obituary of David Sayre (1924-2012)
by Janos Kirz,

Physics Today ''Physics Today'' is the membership magazine of the American Institute of Physics. First published in May 1948, it is issued on a monthly schedule, and is provided to the members of ten physics societies, including the American Physical Society. I ...

DOI:10.1063/PT.4.1769 * Link to David Sayre's Memoir written by himsel

{{DEFAULTSORT:Sayre, David 1924 births 2012 deaths Alumni of the University of Oxford 20th-century American mathematicians 21st-century American mathematicians American physicists Fortran Scientists from New York City Programming language designers Programming language researchers Yale University alumni Mathematicians from New York (state) Presidents of the American Crystallographic Association