ON A CHARACTERISTIC FEATURE OF GRAZING-INCIDENCE NUCLEAR MONOCHROMATORS FOR SYNCHROTRON-RADIATION

It is shown theoretically that the optimum resonance monochromatizatio n of synchrotron radiation by means of grazing-incidence antireflectio n mirrors is obtained not at the maximum possible enrichment (similar to 100%) but rather with a low enrichment in the Mossbauer isotope (th e natural abundance in the case of iron). This possibility is due to t he fact that the conditions of interferometric suppression of electron reflection in the range of total external reflection angles is unique ly sensitive to small variations of the film or substrate density. (C) 1998 American Institute of Physics. [S0021-3640(98)00318-1]