Guard region for radiation sensor

A method of manufacturing a radiation imaging apparatus, comprising:

• providing a substrate with a radiation-sensitive imaging region therein, wherein the radiation-sensitive imaging region comprises a plurality of pixels disposed on a surface of the substrate, wherein each pixel of the plurality of pixels is configured to act as a detector element;
• forming a guard region including a plurality of guard rings on the surface about a periphery of the radiation-sensitive imaging region at or immediately adjacent a cut edge of the substrate and to prevent premature electrical breakdown of the radiation imaging apparatus when the radiation imaging apparatus is in use, wherein the guard region forms an inactive region about the periphery of the radiation-sensitive imaging region;
• and
• forming at least one trench in the surface in the guard region disposed about the periphery of the radiation-sensitive imaging region to improve detection efficiency of pixels of the plurality of pixels located closest to the cut edge when the radiation imaging apparatus is in use while reducing a width of the guard region.

A photon-counting X-ray detector, comprising:

• a plurality of detector sub-modules, wherein each detector sub-module includes:
• a semiconductor layer;
• a radiation-sensitive imaging region in the semiconductor layer, wherein the radiation-sensitive imaging region comprises a plurality of pixels disposed on a surface of the semiconductor layer, wherein each pixel of the plurality of pixels is configured to act as a detector element;
• and
• a guard region disposed on the surface and including a plurality of guard rings disposed about a periphery of the radiation-sensitive imaging region at or immediately adjacent a cut edge of the semiconductor layer, wherein the guard region is configured to prevent premature electrical breakdown of the detector sub-module, wherein the guard region forms an inactive region about the periphery of the radiation-sensitive imaging region, and the guard region comprises at least one trench formed in the surface in the guard region disposed about the periphery of the radiation-sensitive imaging region, and wherein the at least one trench is configured to improve detection efficiency of pixels of the plurality of pixels located closest to the cut edge while reducing a width of the guard region.