DOUBLE-CRYSTAL MONOCHROMATOR FOR HIGH-POWER AND HIGH-ENERGY SYNCHROTRON RADIATION

The performance of the fixed-exit-beam sagittal-focusing double-crystal monochromator installed in the elliptical-multipole wiggler beam line at the 6.5-GeV accumulation ring for the TRISTAN project is reported. The first crystal of the monochromator is directly water cooled. Because of its large size, the crystal deformation made by the cooling water pressure and the mounting method of the crystal is found to be a serious problem. The second bent crystal for sagittal focusing and the adjusting mechanisms must be also cooled to avoid the heating by Compton scattered x rays from the first crystal. It is important for the double-crystal monochromator installed in the high-power and high-energy beam line to cool various components in addition to the first crystal.