X-RAY TUBE

• Main Authors: TSUBURAYA YOSHIAKI, KOYANAGI KEIJI
• Format: Patent
• Language: English
• Published: 18.12.1998
• Edition: 6
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY

PROBLEM TO BE SOLVED: To provide an X-ray tube wherein X-ray intensity distribution pattern of a focus on its positive electrode target is improved and bimodal property thereof is reduced. SOLUTION: A filament attached to a focusing groove 14 of a focusing electrode 3 of a negative electrode consists of a main filament 11 having a larger outer diameter and an auxiliary filament 12 having a smaller outer diameter, both of these being coil-shaped, the auxiliary filament being arranged inside the main filament, these have the same coil pitch and are arranged in half a pitch shifted manner from each other. Coil apices 12A of the auxiliary filament 12 are each situated in the middle of adjacent coil apices 11A. When an X-ray tube voltage is applied, an accelerating electric field is generated in a peripheral part of the coil apices 12A of the auxiliary filament 12, and electron beams from the apices also contribute to focus formation. Since the beams have small single modal intensity distribution, when electron beams of the two filaments 11, 12 are composited, bimodal intensity distribution by electron beams of the main filament 11 comes to have a shallow trough in its center part and approximates to the single modal intensity distribution.