X-ray tube and method of manufacturing the same

A method of manufacturing an X-ray tube comprising a cathode,

• the cathode comprising:
• a filament comprising a coil emitting electrons, and a leg portion extending from the coil to a distal portion and including a first corner portion and a second corner portion at the distal portion,
• a support terminal including a gap, and comprising an opening portion in which the gap is opened and a bottom portion located an end portion of the gap on a side opposite to the opening portion, and
• a cathode cup accommodating the filament and the support terminal and being connected to the support terminal,
• the method comprising:
• inserting the distal portion of the leg portion into the gap of the support terminal;
• supplying a current while applying a pressure to a first surface of the support terminal on an outer side and a second surface of the support terminal located outside on an opposite side with the leg portion sandwiched between the first surface and the second surface, by a pair of electrodes;
• urging a third surface of the support terminal in the gap on a side opposite to the first surface to abut on the first corner portion;
• joining the third surface to the first corner portion;
• urging a fourth surface in the gap of the support terminal opposed to the third surface on a side opposite to the second surface to abut on the second corner portion;
• joining the fourth surface to the second corner portion;
• and
• forming a protruding portion located more closely to the bottom portion side than to the distal portion at a position between the distal portion and the bottom portion, in the gap.