Present status of stability improvement of SPring-8 standard x-ray monochromators

For the stabilization of the SPring-8 double-crystal monochromator with water-cooled inclined-cut silicon crystals, we have changed the water path of the first, crystal, remodeled the crystal holders and attached x-ray and electron shield parts. The improvements are effective to supply, constant-intensity microbeam, to extend the life. time of the elastomer O-rings for water seal, and to decrease the radiation damages of the electric cables of the motors. The 1 angstrom microbeam with the size of 50 mu m x 50 mu m at an experimental station keeps constant intensity, though the intensity decreased by 26% per hour before the improvements. The vibration of the mechanical stages is discussed as the remaining problem.