Lawrence Bragg, microdiffraction and X-ray lasers
- Arizona State Univ., Tempe, AZ (United States)
We trace the historical development of W. L. Bragg's `law' and the key experimental observation which made it possible using polychromatic radiation at a time when neither X-ray wavelengths nor cell constants were known. This led, through his phasing and solving large mineral structures (without use of a computer), to work on metals, proteins, bubble rafts and his X-ray microscope. The relationship of this to early X-ray microdiffraction is outlined, followed by a brief review of electron microdiffraction methods, where electron-probe sizes smaller than one unit cell can be formed with an interesting `failure' of Bragg's law. We end with a review of recent femtosecond X-ray `snapshot' diffraction from protein nanocrystals, using an X-ray laser which generates pulses so short that they terminate before radiation damage can commence, yet subsequently destroy the sample. Using short pulses instead of freezing, the nexus between dose, resolution and crystal size has been broken, opening the way to time-resolved diffraction without damage for a stream of identical particles.
- Research Organization:
- Arizona State Univ., Tempe, AZ (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- FG03-02ER45996
- OSTI ID:
- 1158815
- Report Number(s):
- DOE-ASU-45996
- Journal Information:
- Acta Crystallographica. Section A, Foundations of Crystallography, Vol. 69, Issue 6; ISSN 0108-7673
- Publisher:
- International Union of Crystallography
- Country of Publication:
- United States
- Language:
- English
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