Resolution of a bent-crystal spectrometer for X-ray free-electron laser pulses: diamond versus silicon

Abstract

The resolution function of a spectrometer based on a strongly bent single crystal (bending radius of 10 cm or less) is evaluated. It is shown that the resolution is controlled by two parameters: (i) the ratio of the lattice spacing of the chosen reflection to the crystal thickness and (ii) a single parameter comprising crystal thickness, its bending radius, distance to a detector, and anisotropic elastic constants of the chosen crystal. The results allow the optimization of the parameters of bent-crystal spectrometers for the hard X-ray free-electron laser sources.

X-ray beam diagnostics at the MID instrument of the European X-ray Free-Electron Laser Facility

“…The experimental procedure to measure the spectrum is straightforward, but comprehensive understanding of the measured intensity distribution in the context of diffraction and wave properties requires theoretical efforts. The effect of the strong bending on the diffraction behavior and the consequent limitations of the achievable energy resolution determined by the setup have been investigated by theoretical modeling (Kaganer et al, 2020(Kaganer et al, , 2021Samoylova et al, 2019;Petrov, 2022). For the thin and strongly bent crystals used in the MID setup, dynamical diffraction effects were found to be negligible.…”

Двойное Комптоновское Рассеяние Фотона Атомным Ионом

“…для учета ненулевой ширины спектрального разрешения современного эксперимента (например, Ŵ beam = 0.50 eV в экспериментах с рентгеновским лазером на свободных электронах [24] и Ŵ beam = 5 eV в астрофизике [25]). Наконец, добавим следующее.…”