Protein Crystal Diffraction Patterns Using a Capillary-Focused Synchrotron X-ray Beam.

A paraboloidally tapered glass monocapillary was used to focus an 8 keV monochromated synchrotron bending-magnet X-ray beam into a 40 (+/-5) mum focal spot located 45 (+/-5) mm from the exit of the capillary. This focal spot had a measured intensity gain of 120 (+/-10) times the intensity present in an equivalent cross section of the unfocused beam from the monochromator. This focused beam was used to obtain oscillation diffraction patterns on image plates from a hen egg-white lysozyme protein crystal in two distinct geometries: one with the specimen crystal at the capillary exit and the other with the crystal at the beam focus.

X-ray optics of tapered capillaries.

The optics of x-ray concentration by tapered glass capillaries is analyzed in terms of a phase-space construction describing their transmission efficiency. The parameters defining the intensity gain are given in terms of parameters describing the x-ray source used, the capillary taper profile, and glass characteristics. We introduce some key concepts in understanding these devices: the extreme ray and a phase-space description of sources and optics.

Focusing of X-rays by Total External Reflection from a Paraboloidally Tapered Glass Capillary.

The first observation of a true geometrical focus of X-rays well beyond the exit of a paraboloidally tapered glass monocapillary is reported. An intensity gain of 250 +/- 20 into a 6 x 9 mum pinhole for 8 keV X-rays and transmission efficiencies of more than 90% below 20 keV were observed.