Electric field reduction in the high voltage multiplier module in medical X-ray machines

High voltage multiplier is widely used in the main power supply in medical X-ray machines. The output voltage can be above 100kV. Such a voltage leads to strong electric field in the multiplier. In this paper, the distribution of the electric field strength is analyzed based on the results obtained through 3D finite element (FE) field simulation. The distribution can be expressed as a function containing parasitic capacitances, which simply leads to a shielding technique for the field reduction. The shielding technique is applied in a 4-stage multiplier module and the resultant field reduction is proven by 3D FE simulation.