He, JH (reprint author), Acad Sinica, Shanghai Inst Nucl Res, POB 800-204, Shanghai 201800, Peoples R China.
A double crystal monochromator of sagittal focusing has been designed, based on the idea of the separate movements of the crystal and the independent adjustment of crystal orientations, to be able to work in both the fixed beam exit and the variable beam exit cases. Three sorts of flexure hinge mechanisms have been used to bend the focusing crystal and to adjust the crystal orientations independently. The first crystal of the monochromator is cooled directly by water feeding through the rotation axis. The performance of the monochromator has been tested off-line, and the results show that the adjusting precision of the crystal orientations is better than 0.5 arcsecond and the horizontal width of the focusing image deviates from the theoretical width by less than 25%.