Safe control [X-ray tubes]

Most X-ray tubes in scientific and industrial applications use filaments that are floating at a high voltage, typically 50 kV to 160 kV, from ground. The beam current taken by the X-ray tube, and hence the quantity of X-rays produced, is a function of the temperature of the filament; the hotter the filament the greater the beam current and the more X-rays. Also, the filament must run at a very high temperature before any emission is produced, so careful control of power in the filament is essential. This article looks at how the latest filament control circuits protect X-ray tubes.