a high purity germanium radiation detector has been specially machined to be this invented series multi - chamber coaxial configuration . so extra - large volume hpge detectors can be easily produced with current available hpge crystal , and the entire detector body structure can be uniquely optimized in accordance with the exact semiconductor crystal ingot situation so the overall detector can be easier depleted and the photo - induced carriers can be better collected as the signal output . this invention makes extra - large efficiency hpge gamma ray detectors of 100 % to 200 %, and maybe even higher efficiency , possible and easier to be produced based on current hpge crystal supply capability . the invention improves the detector performance for very high energy gamma ray detection especially . the invention could also be applied to any other kind of semiconductor materials if any of them could be purified enough for this application in future .