David Sayre | |
|---|---|
| Born | (1924-03-02)March 2, 1924 |
| Died | February 23, 2012(2012-02-23) (aged 87) |
| Alma mater | Yale University Oxford University |
| Known for | Sayre equation X-ray microscopy Coherent diffraction imaging FORTRAN |
| Awards | Ewald Prize |
| Scientific career | |
| Fields | X-ray crystallography X-ray microscopy |
| Institutions | IBM Stony Brook University |
| Doctoral advisor | Dorothy Hodgkin |
| Doctoral students | Jianwei (John) Miao |
| Other notable students | Henry N. Chapman |
David Sayre (March 2, 1924 – February 23, 2012) was an American scientist, credited with the early development ofdirect methods forprotein crystallography and of diffraction microscopy (also calledcoherent diffraction imaging). While working at IBM he was part of the initial team of ten programmers who createdFORTRAN, and later suggested the use ofelectron beam lithography for the fabrication of X-rayFresnel zone plates.
TheInternational Union of Crystallography awarded Sayre theEwald Prize 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(...)".[2]
Sayre was born inNew York City. He completed his bachelor's degree in physics atYale University at the age of 19. After working at theMIT Radiation Laboratory, he earned his MS degree atAuburn University in 1948. In 1949, he moved to Oxford with his wifeAnne Colquhoun, whom he had married in 1947. Sayre completed his doctoral studies inDorothy Hodgkin's group in 1951. It is at this time that Sayre discovered theequation now named after him, based on the concept of atomicity. Although the key to mostdirect 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 byClaude Shannon'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 recentlensless imaging techniques.
Back in United States, David Sayre worked on structure determination of a carcinogen molecule in the lab of Peter Friedlander at theUniversity of Pennsylvania inPhiladelphia. The structure determination program he wrote for the IBM 701 attracted the attention ofJohn Backus, 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 developedelectron beam lithography apparatus at IBM to produceFresnel 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.
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