Patent ID: 9374881
Filing Date: 2016-06-21
CPC Classification: H05G

Claim Text:
1. A radiation generator comprising: a radiation tube including: a grid-voltage generating unit configured to apply an extraction voltage to the grid electrode in response to an external request for radiation output; a cathode heater driver configured to generate a cathode heater voltage; a cut-off voltage generating unit configured to generate a cut-off voltage applied to the grid electrode so as to lower the potential of the grid electrode relative to the potential of the electron emitting cathode when there is no external request for the radiation output; a lens electrode driver configured to generate a lens electrode voltage applied to the lens electrode; and a detection unit including a primary switching circuit and a secondary switching circuit, the primary switching circuit configured to turn off energizing to the cathode heater and configured to detect a decrease in the cut-off voltage with respect to the electron emitting cathode, and the secondary switching circuit configured to turn off energizing to the lens electrode, wherein, when the decrease in the cut-off voltage is detected, the primary switching circuit turns off energizing to the cathode heater such that the target is not irradiated by the electrons.