How x-ray diffraction with synchrotron radiation got started
The need to record low angle scattering x-ray fibre diagrams from muscle with milli-second time resolution drove the use of synchrotron radiation as an x-ray light source. The first smudgy diffraction patterns were obtained from a slice of insect flight muscle. Out of this grew the EMBL Outstation at DESY.
The initial success at DESY sparked world wide interest. In June 1972 there was a historical meeting in Brookhaven at which most of the subsequent applications of x-ray synchrotron radiation were discussed (see -BNLReport 1973). The most important application for biology later proved to be protein crystallography. Early tests of protein diffraction on the DESY source (Harmsen et al ., 1976) showed improvements compared with conventional sources but the gains were limited. The flux was about ten times better than with a conventional source. At this stage one had failed to appreciate that the parallel collimation of the beam was giving unusually good signal/noise. This was the property of synchrotron radiation which ultimately made it the source of choice for all kinds of protein crystal data collection. About the same time studies on the Stanford storage ring SPEAR (Phillips et al ., 1976) showed gains for crystal diffraction even with a non-focusing monochromator which showed clearly that storage ring sources were to be of considerable importance in protein crystallography. These authors made use of the ability to "tune" the wavelength across an adsorption edge to demonstrate the potentialities of synchrotron radiation in exploiting the effects of anomalous dispersion.