Probing the Linewidth of the 12.4-keV 45 Sc Isomeric Resonance in Solids by Nuclear Forward Scattering
Researchers used XFEL pulses to excite a solid-state 45Sc isomer and measured its lifetime using fluorescence. They found the natural linewidth is very narrow, but experimental conditions imply an inhomogeneous broadening of at least 500 times the natural linewidth. This sets a benchmark for developing solid-state nuclear clocks.