X-RAY TUBE

摘要

An X-ray tube is provided with an anode target, a cathode comprising an electron emission source and a convergence electrode, and a vacuum envelope. The convergence electrode includes a groove portion (16) in which the electron emission source is housed, and converges an electron beam. The groove portion (16) has a nearest inner peripheral wall (53), an upper inner peripheral wall (51) and a lower inner peripheral wall (52). The nearest inner peripheral wall (53) is shorter than the dimension of the electron emission source in the depth direction of the groove portion and faces the electron emission source over the entire periphery with a narrowest clearance therebetween in the width direction of the groove portion. The upper inner peripheral wall (51) is located on the open side of the groove portion from the nearest inner peripheral wall (53) and has a shape wider than the nearest inner peripheral wall (53) in the width direction. The lower inner peripheral wall (52) is located on the side opposite to the upper inner peripheral wall (51) with respect to the nearest inner peripheral wall (53), and has a shape wider than the nearest inner peripheral wall (53) in the width direction.