PARTICLE ACCELERATORS OF THE NUCLEAR RADIATION SOURCE TYPE FOR USE IN SCIENTIFIC RESEARCH, AND INDUSTRY, AND TO ACCESSORIES AND AUXILIARY EQUIPMENT THEREFOR-NAMELY, ACTUATORS, BEAM TUBE SUPPORTS, BELLOWS, CHAMBERS, FOCUS RINGS, IONIZATION GAUGES, ADAPTERS, TARGETS, GATE VALVES, VIEWERS, AND UNIONS ADAPTED FOR USE WITH PARTICLE ACCELERATORS