A radiation generator includes an insulator, with an ion source carried within the insulator and configured to generate ions and indirectly generate undesirable particles. An extractor electrode is carried within the insulator downstream of the ion source and has a first potential. An intermediate electrode is carried within the insulator downstream of the extractor electrode at a ground potential and is shaped to capture the undesirable conductive particles. In addition, a suppressor electrode is carried within the insulator downstream of the intermediate electrode and has a second potential opposite in sign to the first potential. A target is carried within the insulator downstream of the suppressor electrode. The extractor electrode and the suppressor electrode have a voltage therebetween such that an electric field generated in the insulator accelerates the ions generated by the ion source toward the target.