hv2‐concept breaks the photon‐count limit of RIXS instrumentation.

Upon progressive refinement of energy resolution, the conventional resonant inelastic X‐ray scattering (RIXS) instrumentation reaches the limit where the bandwidth of incident photons becomes insufficient to deliver an acceptable photon‐count rate. Here it is shown that RIXS spectra as a function of energy loss are essentially invariant to their integration over incident energies within the core‐hole lifetime. This fact permits RIXS instrumentation based on the hv2‐concept to utilize incident synchrotron radiation over the whole core‐hole lifetime window without any compromise on the much finer energy‐loss resolution, thereby breaking the photon‐count limit. [ABSTRACT FROM AUTHOR]