  We introduce a time-delayed beam splitting method based on the energy
separation of x-ray photon beams. It is implemented and theoretically
substantiated on an example of an x-ray optical scheme similar to that of the
classical Michelson interferometer. The splitter/mixer uses Bragg-case
diffraction from a thin diamond crystal. Another two diamond crystals are used
as back-reflectors. For energy separation the back-reflectors are set at
slightly different temperatures and angular deviations from exact
backscattering. Because of energy separation and a minimal number (three) of
optical elements, the split-delay line has high efficiency and is simple to
operate. Due to the high transparency of diamond crystal, the split-delay line
can be used in a beam sharing mode at x-ray free-electron laser facilities. The
delay line can be made more compact by adding a fourth crystal.
