| 976 / | HD | NUCLEAR TECHNOLOGY |
| DIG 427 | DD | ARRANGEMENTS FOR HANDLING RADIATION OR PARTICLES (e.g., focusing, moderating [G21K-1/00] *** (radiation filters DIG. 435) {6} |
| DIG 428 | DD | .~ Using diaphragms, collimators [G21K-1/02] {2} |
| DIG 430 | | .~.~ Using variable diaphragms, shutters, choppers [G21K-1/04] |