SUBMICRON X-RAY MICROBEAM PRODUCTION WITH A WOLTER-TYPE GRAZING-INCIDENCE MIRROR AT TRISTAN MAIN RING (KEK)

Tristan Main Ring (MR) at KEK in Japan was temporarily operated as a s ynchrotron radiation source from September to December in 1995. The ma chine was operated at 8Gev and the beam current was several mA during our experiment. Although our machine time was limited to only five day s, the results were very useful. A quasi-monochromatic beam from the u ndulator was monochromatized by two silicon parallel crystals. An 8.5k eV monochromatic X-ray beam was focused by the Welter-type grazing inc idence mirror which consists of paraboloidal and hyperboloidal inner s urfaces. The distance between the undulator and the mirror was 100m, w hich gave rise to a relatively large coherent area (vertical similar t o 50 mu m, horizontal similar to 30 mu m) at the entrance plane of the mirror. A highly collimated beam (vertical divergence similar to 3 mu rad, horizontal similar to 5 mu rad) was so sensitive to the mirror s urface undulation that several focal spots were produced. The shape of the spots were nearly elliptical. The smallest diameter of the spots was less than 1 mu m.