Disclosed is an X-ray sensor having an active detector region including detector diodes on its surface. The X-ray sensor further includes a junction termination surrounding the surface region including the detector diodes. The junction termination includes a guard arranged closest to the end of the surface region, a field stop outside the guard and at least two field limiting rings, FLRs arranged between the guard and the field stop. A first FLR is arranged at a distance Δ1 from the guard selected from the interval [4 μm; 12 μm], a second FLR is arranged at a distance Δ2 from the first FLR selected from the interval [6.5 μm; 14 μm], and wherein the distance Δ2 is larger than the distance Δ1. The proposed technology also provides a method for constructing such an X-ray sensor and an X-ray imaging system including an X-ray detector system that includes such X-ray sensor.