A radiation detector (20, 30), comprising: a read-out sensor array, a first scintillator structure, a second scintillator structure and a coating, wherein the read-out sensor array comprises a plurality of light-sensitive sensor pixels; wherein the first scintillator structure comprises a plurality of first scintillator pixels (24a, 34a) separated by gaps (25a, 35a); wherein the second scintillator structure is optically coupled to the first scintillator structure; wherein the first scintillator structure and the second scintillator structure are arranged between the coating and the read-out sensor array; wherein the second scintillator structure at least partially overlaps the gaps (25a, 35a) between the first scintillator pixels (24a, 34a) of the first scintillator structure; wherein the second scintillator structure comprises a plurality of second scintillator pixels (23a, 33a) separated by gaps; wherein at least one second scintillator pixel at least partially overlaps a gap between the first scintillator pixels (24a, 34a); characterised in that the first scintillator structure comprises ceramic scintillator material; wherein the second scintillator structure comprises particle-in-binder scintillator material; and wherein the at least one second scintillator pixel comprises a slanted surface section, which is inclined relative to a layer formed by the first scintillator structure to reflect light from inside the at least one second scintillator pixel towards a first scintillator pixel, which is optically coupled to the at least one second scintillator pixel; or wherein the at least one second scintillator pixel is tilted relative to the layer formed by the first scintillator structure to increase a gap between the at least one second scintillator pixel and a first scintillator pixel, which is not optically coupled to the at least one second scintillator pixel. a read-out sensor array, a first scintillator structure, a second scintillator structure and a coating, wherein the read-out sensor array comprises a plurality of light-sensitive sensor pixels; wherein the first scintillator structure comprises a plurality of first scintillator pixels (24a, 34a) separated by gaps (25a, 35a); wherein the second scintillator structure is optically coupled to the first scintillator structure; wherein the first scintillator structure and the second scintillator structure are arranged between the coating and the read-out sensor array; wherein the second scintillator structure at least partially overlaps the gaps (25a, 35a) between the first scintillator pixels (24a, 34a) of the first scintillator structure; wherein the second scintillator structure comprises a plurality of second scintillator pixels (23a, 33a) separated by gaps; wherein at least one second scintillator pixel at least partially overlaps a gap between the first scintillator pixels (24a, 34a); characterised in that the first scintillator structure comprises ceramic scintillator material; wherein the second scintillator structure comprises particle-in-binder scintillator material; and wherein the at least one second scintillator pixel comprises a slanted surface section, which is inclined relative to a layer formed by the first scintillator structure to reflect light from inside the at least one second scintillator pixel towards a first scintillator pixel, which is optically coupled to the at least one second scintillator pixel; or wherein the at least one second scintillator pixel is tilted relative to the layer formed by the first scintillator structure to increase a gap between the at least one second scintillator pixel and a first scintillator pixel, which is not optically coupled to the at least one second scintillator pixel.