CHARACTERIZATION OF X-RAY DIFFRACTION SYSTEM WITH A MICROFOCUS X-RAY SOURCE AND A POLYCAPILLARY OPTIC

摘要

We present here an optimized microfocus x-ray source and polycapillary optic system designed for diffraction of small protein crystals. The x-ray beam is formed by a 5.5mm input focal length capillary collimator coupled with a 40 micron x-ray source operating at 46Watts. Measurements of the x-ray flux, the divergence and the spectral characteristics of the beam are presented. This optimized system provides a seven fold greater flux than our recently reported configuration [M. Gubarev, et aL, J. of Applied Crystallography (2000) 33, 882-887]. We now make a comparison with a 5kWatts rotating anode generator (Rigaku) coupled with confocal multilayer focusing mirrors (Osmic, CMF12-38Cu6). The microfocus x-ray source and polycapillary collimator system delivers 60% of the x-ray flux from the rotating anode system. Additional ways to improve our microfocus x-ray system, and thus increase the x-ray flux will be discussed.