A load-side voltage detection module for a metrology device includes a plurality of first resistors electrically coupled to a first load-side terminal, the first resistors being in series, a plurality of second resistors electrically coupled to a second load-side terminal, the second resistors being in series, a voltage divider electrically coupled between a first line-side terminal and a second line-side terminal, the voltage divider creating a reference voltage for the load-side voltage detection module, and a pulse generator to generate a pulse based on detection of voltage, the pulse indicating a voltage on at least one of the first load-side terminal or the second load-side terminal, above at least one threshold.

According to one embodiment, an X-ray tube includes an anode target, a cathode including a filament and a convergence electrode which includes a groove portion, and an envelope. The groove portion includes a pair of first bottom surfaces which are located in the same plane as the filament and between which the filament is interposed in a width direction of the groove portion, and a pair of second bottom surfaces between which the filament and the pair of first bottom surfaces are interposed in a length direction of the groove portion and which are located closer to an opening of the groove portion than the pair of first bottom surfaces.

According to one embodiment, an X-ray tube includes an anode target, a cathode including a filament and a convergence electrode which includes a groove portion, and an envelope. The groove portion includes a pair of first bottom surfaces which are located in the same plane as the filament and between which the filament is interposed in a width direction of the groove portion, and a pair of second bottom surfaces between which the filament and the pair of first bottom surfaces are interposed in a length direction of the groove portion and which are located closer to an opening of the groove portion than the pair of first bottom surfaces.