  Spontaneous parametric down-conversion is a vital method for generating
correlated photon pairs in the visible and near-infrared spectral regions;
however, its extension to X-ray frequencies has faced substantial barriers.
Here, we present an advancement in correlated X-ray pair generation and
detection by employing a two-dimensional pixelated detector to obtain the first
direct image of the pair distribution. Our study explores and directly
visualizes the down-conversion process, revealing the characteristic ring
structure of coincident photon pairs and demonstrating robust spatial
correlations. A significant finding is the observation of energy
anti-correlation, achieved at an unprecedented rate of approximately 4,100
pairs/hour, far exceeding previous reports in the literature. We believe these
results represent a significant leap in X-ray quantum imaging, unlocking the
potential for enhanced imaging of biological materials with reduced doses and
broadening the applicability of X-ray quantum optical technologies.
