X-ray tube & rotating anode construction
Schematic cut-through of a diagnostic x-ray tube inside an oil-filled housing. On the left a heated filament sits in a negative focusing cup (cathode); electrons boil off by thermionic emission and are accelerated across the evacuated envelope by 60 to 120 kV. They strike the angled tungsten-rhenium focal track of a rotating anode disc (molybdenum/graphite body, molybdenum stem, driven by a rotor and external stator), where about 1 percent of their energy becomes x-rays and 99 percent becomes heat. The useful x-ray beam leaves roughly perpendicular to the electron path, downward through the window; heat is spread by rotation and lost mainly by radiation.
Practice the Physics paper
FRCRX is a Part 1 Physics question bank: true/false items with explanations, timed mocks and topic analytics.