Abstract: An x-ray detector module comprises a plurality of silicon drift detector cells arranged next to each other on a sensor chip. The sensor chip is arranged in a recess of a frame-shaped base support, such that the sensitive chip surface lies in the opening of the frame-shaped base support. A mask (10) is fixed to the side of the base support (2) opposite to the recess and covers the outer edge areas of external detector cells and ridges above the sensor chip (8) protrude into the opening of the base support (2). The ridges are arranged in such a manner that they cover the defining strips which are adjacent to the detector cells, in order to protect the external edge areas and the defining strips which are covered by the mask (10) counter to the incident x-ray photons.