Currents and fields reveal the propagation of nuclear polaritons through a resonant target

Nuclear resonant scattering of synchrotron radiation was investigated simultaneously in the spatially incoherent (4π) and in the spatially coherent (forward) scattering channels. A theory is presented which describes the main contributions to the scattering picture. To observe the 4π scattering, a nuclear target (spectator) was employed which was mounted downstream of another target (emitter). Emitter and spectator formed a combined scattering system. The time evolutions of the 4π scattering from the spectator and of the forward scattering from the combined system were measured and compared for different thicknesses of emitter and spectator. These observations and the analysis of the obtained time evolutions reveal how nuclear polaritons propagate through a scattering system