High-energy-resolution x-ray optics with refractive collimators

We have tested the concept of a high-resolution x-ray monochromator with a refractive collimator as an optical element. Two options were examined, whe re the refractive collimator was included either instead of, or in addition to the first crystal of the high-resolution monochromator. The first appro ach offers an easy means of improving the energy resolution of conventional optical schemes by few orders of magnitude while still accepting the entir e angular divergence of the primary beam. The second approach improves the performance of existing devices with very high-energy resolution and simpli fies the design of future optical schemes. (C) 2000 American Institute of P hysics. [S0003-6951(00)04927-5].